Antimalarials

Our research corroborates that of other investigators that malaria prophylaxis is an often neglected or intentionally avoided aspect of caring for the pregnant traveler--frequently with disastrous results. We present here the case for providing adequate medical prophylaxis, as well as some guidance regarding the choice of agent.

General

1. Bruel H, Poinsot J, Chabrolle JP. [Neutropenia in a newborn secondary to sulfamethoxazole-trimethoprim administered to the mother]. Arch Pediatr 1999 Jan;6(1):107-8 [Article in French]

2. Silver HM. Malarial Infection during pregnancy. Infections in obstetrics. Infectious disease clinics of North America. 1997;11:99-107. This article reviews the parasitology of malaria, epidemiology in pregnancy, pathogenesis of increased susceptibility to infection in pregnancy, the effect of pregnancy on the clinical manifestations of malaria, the effect of malaria on perinatal outcomes, the safety of antimalarial agents during pregnancy, the role of chemoprophylaxis for inhabitants and travelers to endemic areas, and treatment of clinical malarial infections during pregnancy.

3. Parke AL.Antimalarial drugs in pregnancy.Scand J Rheumatol Suppl 1998;107:125-7

4. Parke AL, Rothfield NF. Antimalarial drugs in pregnancy--the North American experience. Lupus 1996 Jun;5 Suppl 1:S67-9. The use of the 4-aminoquinoline antimalarials in pregnancy is controversial. The current practice of discontinuing these medications because of pregnancy makes little sense as the half-life of these medications is so long. Patients with SLE have increased fetal wastage and one of the factors known to contribute to this fetal wastage is disease activity. It is also known that discontinuing the 4-aminoquinoline antimalarial drugs can precipitate flares of disease in lupus patients. Mothers and their potential offspring are therefore at risk for flares of disease and pregnancy failure if these medications are discontinued because of pregnancy. This review addresses the North American experience of the use of antimalarial drugs in pregnant lupus patients. Unlike most centers in North America, we continue our patients on these medications throughout pregnancy and to date have documented 16 lupus patients who have taken these drugs throughout pregnancy. Our most recent study documents nine pregnancies in eight women. All of these pregnancies resulted in live births (five pre-term deliveries and four full-term deliveries). There were no congenital abnormalities in these infants and follow-up to date has revealed no evidence of ocular or oral deficits in any of these children. One patient experienced a flare of disease when her antimalarial therapy was temporarily discontinued.

5. Phillips-Howard PA, Wood D. The safety of antimalarial drugs in pregnancy. Drug Saf 1996 Mar;14(3):131-45. Alternative drugs to chloroquine are required to prevent the deleterious effects of malaria in pregnancy. Fear of potential toxicity has limited antimalarial drug use in pregnancy. Animal toxicity studies have documented teratogenicity when antimalarials are administered at high dosages. Excepting the tetracyclines, there is no evidence to suggest that, at standard dosages, any of the antimalarial drugs are teratogenic. Primaquine is not recommended because of the potential risk of haemolytic effects in the fetus. Rates of spontaneous abortion and birth defects were comparable in pregnant women taking mefloquine, compared with chloroquine-proguanil, or pyrimethamine-sulfadoxine prophylaxis, in the first trimester of pregnancy. Standard doses of quinine do not increase the risk of abortion or preterm delivery. Therapeutic mefloquine does not provoke hypoglycaemia. There is no evidence in the literature to support the hypothetical risk of kernicterus in the newborn, following exposure to antimalarial drugs containing sulphonamides or sulphones prior to delivery. Documentation of the safety of doxycycline, halofantrine, and the artemisinin derivatives in the treatment of malaria in pregnant women is currently limited.

6. Rosenblatt JE. Antiparasitic agents. Mayo Clinic Proceedings 1999 Nov;74(11):1161-75. Several important developments have occurred in recent years in the chemotherapy for and prophylaxis of parasitic infections. Although mefloquine is clearly the most effective agent for prevention of chloroquine-resistant falciparum malaria, its use has been compromised by side effects, both real and imagined. Well-designed studies have shown that side effects occur no more frequently with low-dose mefloquine than with chloroquine. Use of mefloquine in pregnant women has not been associated with birth defects, but the incidence of stillbirths may be increased. Malarone is a new agent that combines atovaquone and proguanil, and it may be as effective as mefloquine; however, it is not yet available in the United States. Several newer agents have appeared in response to the development of multidrug resistant Plasmodium falciparum, especially in Southeast Asia. Halofantrine is available for the treatment of mild to moderate malaria due to P. falciparum and for P. vivax infections. Because of severe toxic effects, use of halofantrine should be restricted to only those unusual and rare situations in which other agents cannot be used. Artemisinin (an extract of the Chinese herbal remedy qinghaosu) and two derivatives, artesunate and artemether, are active against multidrug resistant P. falciparum and are widely used in Asia in oral, parenteral, and rectal forms. The antibacterial azithromycin in combination with atovaquone or quinine has now been reported to treat babesiosis effectively in experimental animals and in a few patients. Azithromycin in combination with paromomycin has also shown promise in the treatment of cryptosporidiosis (and toxoplasmosis when combined with pyrimethamine) in patients with the acquired immunodeficiency syndrome (AIDS). Albendazole is currently the only systemic agent available for treatment of microsporidiosis, an infection primarily of patients with AIDS. In addition, albendazole and ivermectin have emerged as effective broad-spectrum antihelminthics, with albendazole becoming the drug of choice for hydatid disease (echinococcosis), neurocysticercosis, and most intestinal nematode infections (except strongyloidiasis and trichuriasis). Liposomal amphotericin B is the first drug approved by the Food and Drug Administration for the treatment of visceral leishmaniasis.

7. Garner P, Gulmezoglu AM. Drugs for preventing malaria-related illness in pregnant women and death in the newborn (Cochrane Review). Cochrane Database Syst Rev 2003;(1):CD000169. BACKGROUND: Malaria contributes to maternal illness and anaemia in pregnancy, especially in first-time mothers, and could harm the mother and the baby. Interventions to prevent or mitigate the effects of malaria during pregnancy are often recommended. OBJECTIVES: To assess drugs given to prevent malaria infection and its consequences in pregnant women living in malarial areas. SEARCH STRATEGY: We searched the Cochrane Infectious Diseases Group trials register (July 2002); the Cochrane Controlled Trials Register (Issue 3, 2002); MEDLINE (1966-July 2002); EMBASE (1974-July 2002); and LILACS (accessed July 2002). We contacted researchers in the field. SELECTION CRITERIA: Randomised and quasi-randomised trials in pregnant women of drugs given regularly that aim to mitigate the effects of malaria in pregnancy. DATA COLLECTION AND ANALYSIS: Trial quality was assessed. Data extraction was done by two reviewers using standard criteria. MAIN RESULTS: 14 trials included (n=3454); only 2 were adequately concealed. For women of all parity groups, the meta-analysis (n=2890) showed lower parasitaemia and placental malaria in the intervention arm. For women having the first or second baby, there were 9 studies (n=3454). Severe antenatal anaemia was less common (RR 0.62, 95%CI 0.50 to 0.78, 4 studies), perinatal mortality appeared lower (RR 0.73, 95% CI 0.73 to 0.99, 3 studies). Maternal parasitaemia was lower with the intervention (RR 0.24, 95%CI 0.14 to 0.42, random effects model, 6 studies), and mean birthweight higher (WMD 122 g, 95%I 81 to 164 g, 8 studies), and low birthweight was less common (RR 0.49, 95%CI 0.36 to 0.65, 6 studies). REVIEWER'S CONCLUSIONS: Drugs given routinely for malaria during pregnancy reduce severe antenatal anaemia in the mother, and are associated with higher birthweight and probably reduced perinatal mortality. This effect appears to be limited to low parity women.

8. Phillips-Howard PA, Steffen R, Kerr L, et al. Safety of malaria chemoprophylaxis in pregnancy: indications from exposure in travellers. J Travel Med 1998;5:121–126.

9. Kain KC, Shanks GD, Keystone JS. Malaria chemoprophylaxis in the age of drug resistance. I. Currently recommended drug regimens. Clin Infect Dis 2001 Jul 15;33(2):226-34

10. Garner P, Gulmezoglu AM Prevention versus treatment for malaria in pregnant women. Cochrane Database Syst Rev 2000;(2):CD000169 OBJECTIVES: Malaria contributes to antenatal anaemia and slowing of fetal growth, especially in first-time mothers. It is thought that these effects harm the mother and baby, and interventions to prevent or mitigate the effects of malaria are often recommended. The objective of this review was to assess the effects of anti-malarial interventions in pregnant women living in malarial areas on the mother and the infant. SEARCH STRATEGY: We searched the Cochrane Infectious Diseases Group trials register, the Cochrane Controlled Trials Register, Medline, Embase. We contacted researchers in the field. SELECTION CRITERIA: Randomised and quasi-randomised trials in pregnant women of interventions that aim to mitigate the effects of malaria in pregnancy, including drugs given routinely and mosquito control measures. DATA COLLECTION AND ANALYSIS: Trial quality was assessed. Data extraction was done by two reviewers using standard criteria. MAIN RESULTS: Fifteen trials were included. Drugs given regularly and routinely were associated with fewer episodes of fever in the mother, fewer women with severe anaemia antenatally, and higher average birthweight in infants. These effects appear to be greater in primigravidae. No difference in perinatal, neonatal and infant mortality were detected in studies of prophylaxis in all parity groups, or studies confined to women of low parity. REVIEWER'S CONCLUSIONS: Drugs locally effective for malaria when given routinely for malaria during pregnancy may reduce the incidence of low birth weight and anaemia. This effect appears to be limited to low parity women. Given the costs and inputs required to effectively deliver widescale prophylaxis programmes, we believe a large simple placebo- controlled trial testing the impact of drugs given routinely on pregnancy outcome and neonatal/infant survival is warranted.

11. Lemardeley P, Raiga J, Chambon R, Keuzeta JJ, Foumane V, Chandenier J. [Prevention and control of malaria in pregnant women in an urban setting]. Sante 1997 Jul-Aug;7(4):239-45. [Article in French] The aim of this study was to evaluate the methods of preventing malaria (chemoprophylaxis, vector control) and of fever management (presumptive treatment of malaria) used for pregnant women in Yaounde, Cameroon and to identify the most important factors for assessing these practices. The 221 women studied were selected by cluster sampling. All had made extensive use of health services during pregnancy and 77% were using chemoprophylaxis. The number of febrile episodes in pregnant women who claimed to have used chemoprophylaxis was not significantly different to that in the women who did no`t use it. However, the mean birth weight of the babies of women who had used chemoprophylaxis was significantly higher. The women did not systematically use vector control measures; 21% used insect repellents (electric plaques, coil burners) and 20% used aerosol insecticides. Only 10% of the women slept under simple, untreated mosquito nets and none used mosquito nets impregnated with insecticide. Fifty per cent of the women had at least one episode of fever during pregnancy and 77% were treated for presumed malaria. However, the treatment was not standardized and was unsuitable in a third of cases. Possible changes in the chemoprophylaxis strategy are discussed.

12. McGready R, Nosten F. The Thai-Burmese border: drug studies of Plasmodium falciparum in pregnancy. Plasmodium falciparum malaria is increasing world-wide, as is resistance to the available antimalarials. On the Thai-Burmese border this problem is most acute in pregnant women, as options for their treatment are even more restricted because of the unknown effects of antimalarials on the foetus. Presented here are the results of descriptive, clinical, drug studies on quinine, mefloquine and artemisinin derivatives for P. falciparum in pregnant women. Mefloquine and quinine have high failure rates for primary and recrudescent infections. Artemisinin-based treatments in pregnant women have proved safe, tolerable and efficacious. However, randomized drug studies with these drugs and other new antimalarials are required to define the true safety and efficacy of these drugs in pregnant women.

13. Botelho-Nevers E, Laurencin S, Delmont J, Parola P. Imported malaria in pregnancy: a retrospective study of 18 cases in Marseilles, France. Ann Trop Med Parasitol. 2005 Oct;99(7):715-8. A report that underscores the disastrous results of not providing malaria prophylaxis for pregnant travelers.

Chloroquine

1. Wolfe MS, Cordero JF. Safety of chloroquine in chemosuppression of malaria during pregnancy. Br Med J (Clin Res Ed) 1985 May 18;290(6480):1466-7. A cohort of 169 births to women who were exposed throughout pregnancy to chloroquine 300 mg base once a week for chemosuppression of malaria was studied. The birth defects in this cohort were compared with those in a control group of 454 births to women who were not exposed to chloroquine, most of whom lived in non-malarious areas. The proportion of birth defects in the exposed group was not significantly different from that in the control group. This observation must be considered within the limitations of the study, which could detect only a strong teratogenic effect. It could not exclude risks lower than a 5.7-fold increase in the incidence of birth defects when chloroquine was used. Women using chloroquine during pregnancy for chemosuppression of malaria can be reassured that it is not a strong teratogen, but if it is to be used the risk of developing malaria should be balanced against the lack of data to determine whether it carries a low teratogenic risk.

Mefloquine

1. Steffen R, Fuchs E, Schildknecht J, et al. Mefloquine compared with other malaria chemoprophylactic regimens in tourists visiting East Africa. Lancet 1993;341:1299–1303.

2. Phillips-Howard PA et al. Safety of mefloquine and other antimalarial agents in the first trimester of pregnancy. Journal of Travel Medicine, 1998, 5:121–126. BACKGROUND: Safe and effective antimalarials are required to protect pregnant women from the harmful effects of malaria. METHODS: Data were collected from two separate prospective cohorts to ascertain the safety of chloroquine-proguanil, sulfadoxine-pyrimethamine (SP), and mefloquine taken in the first trimester of pregnancy. RESULTS: In a traveler cohort of 236 pregnant women, spontaneous abortions were reported in 7.6% of 99 women taking chloroquine-proquanil, 0% of 19 taking sulfadoxine-pyrimethamine, and 9.1% of 118 women taking mefloquine. Anomalies were identified in 1.7%, 0% and 0% of the same cohort, respectively. Differences in rates of adverse outcomes between the three groups were not statistically significant. In a pharmaceutical database of 331 and 153 women exposed to mefloquine and SP, respectively, the overall rate of abnormal outcomes (spontaneous abortions plus fetal anomalies) was not significantly different (p=.29). Spontaneous abortions were significantly higher with mefloquine than SP (9.1% and 2.6%, respectively; p=.01), but the higher rate was comparable to background rates (7%-11%). Fetal anomalies in the mefloquine group (4.8%) were lower than the SP group (7.8%), but this was statistically not significant (p=.19), and was comparable with the background rate of 4.6% (p=.84). However, mefloquine exposure resulted in a significantly higher rate of therapeutically induced abortions, undertaken for perceived risk to the fetus, compared with SP (p<.0001). CONCLUSION: From the clinical data available, there is no indication that the risk of taking mefloquine in the first trimester of pregnancy is greater than that from any of the other antimalarials studied and the risk is considerably lower than that associated with falciparum malaria.

3. Na Bangchang K, Davis TM, Looareesuwan S, et. Al. Mefloquine pharmacokinetics in pregnant women with acute falciparum malaria. Trans R Soc Trop Med Hyg 1994;88:321-3 . Mefloquine has an established place in the treatment of chloroquine-resistant falciparum malaria. To investigate mefloquine pharmacokinetics in pregnancy, 9 untreated pregnant women aged 16-33 years and 8 non-pregnant females aged 16-38 years received an average of 15 (range 13-19) mg mefloquine/kg body-weight as single-dose treatment for uncomplicated falciparum malaria. Regular blood samples were taken during the subsequent 48 h and then intermittently for 3-26 d after treatment. Whole blood mefloquine concentrations were analysed by high-performance liquid chromatography and a one-compartment open pharmacokinetic model was fitted to the data. Peak mefloquine concentrations were significantly lower in the pregnant patients (median [range]; 1257 [650-1584] vs. 1617 [1051-3111] ng/mL) and the total apparent volume of distribution (Vd/f) was larger (10.8 [8.3-26.1] vs. 10.0 [4.8-13.9] L/kg; P < 0.05 in each case), consistent with an expanded circulating blood volume and increased tissue binding in pregnancy. There was no significant difference between the 2 groups in half-times of absorption or elimination (P > 0.1), and systemic clearance rates were also similar. These results suggest that pregnant patients need larger doses of mefloquine than non-pregnant women to achieve comparable blood levels, an important consideration in areas where multi-drug resistant falciparum malaria is emerging.

4. Nosten F, Vincenti M, et al. The effects of mefloquine treatment in pregnancy. Clin Infect Dis 1999 Apr;28(4):808-15. We investigated the relationship between mefloquine antimalarial treatment and the outcome of pregnancy in Karen women living in an area along the western border of Thailand where multidrug-resistant Plasmodium falciparum infections are common. Of 3,587 pregnancies investigated, 208 (5.8%) were exposed to mefloquine, 656 (18.3%) to quinine only, and 909 (25.3%) to other antimalarials, and 2,470 (68.9%) had no documented malaria. There were 61 stillbirths and 313 abortions. Women who received mefloquine treatment during but not before pregnancy had a significantly greater risk of stillbirth than did women treated with quinine alone (odds ratio [OR], 4.72; 95% confidence interval [CI], 1.7-12.7), women exposed to other treatments (OR, 5.10; 95% CI, 2-13.1), and women who had no malaria (OR, 3.50; 95% CI, 1.6-7.6) (P < .01). This association remained after adjustment for all identified confounding factors. Mefloquine was not associated with abortion, low birth weight, neurological retardation, or congenital malformations. Mefloquine treatment during pregnancy was associated with an increased risk of stillbirth.

5. Vanhauwere B, Maradit H, Kerr L. Post-marketing surveillance of prophylactic mefloquine (Lariam) use in pregnancy. Am J Trop Med Hyg 1998 Jan;58(1):17-21. The purpose of this study was to evaluate the teratogenic potential of mefloquine (Lariam) in pregnancy, based on the Roche International Spontaneous Reporting System. Lariam is an anti-malarial drug used both in prophylaxis and treatment of malaria. Teratogenic effects were observed in animals but data from humans are lacking. Women of childbearing potential are currently advised to take contraceptive precautions up to three months after the last dose. The study included 1,627 spontaneous reports of women exposed to Lariam before or during pregnancy, which were received by Roche worldwide since introduction on the market. The data were analyzed considering pregnancy and fetal outcome and type of congenital malformations. The birth prevalence of congenital malformations in women exposed to Lariam is estimated to be 4% and is not different from the prevalence observed in the general population. In addition, the congenital malformations observed with Lariam exposure do not show any specific pattern. The data from our study suggest that the teratogenicity, which was observed in animals at high doses, cannot be applied to humans.

6. Smoak BL, Writer JV, Keep LW, Cowan J, Chantelois JL. The effects of inadvertent exposure of mefloquine chemoprophylaxis on pregnancy outcomes and infants of US Army servicewomen. J Infect Dis 1997 Sep;176(3):831-3. During US military operations in Somalia, mefloquine, a drug for malaria chemoprophylaxis, was not approved for use in pregnant women. Some female soldiers inadvertently used mefloquine before becoming aware of their pregnancy. A registry was established to follow the outcomes of these pregnancies. Questionnaires were administered at the time the pregnancy was diagnosed, after termination or delivery, and at 1 year after birth. Seventy-two soldiers were eligible for the registry. There were 17 elective abortions, 12 spontaneous abortions, 1 molar pregnancy, and 23 live births. The outcome for 19 soldiers was unknown. An unexpected high rate of spontaneous abortions was observed. All infants were healthy at birth, with no major congenital malformations. One infant died at 4 months of viral pneumonitis. At 1 year of age, 13 infants were reported to be healthy, with normal cognitive and motor development. This study provides additional postmarketing data that mefloquine does not cause gross congenital malformations.

7. Schlagenhauf P. Mefloquine for malaria chemoprophylaxis 1992-1998: a review. Journal of Travel Medicine 1999 Jun;6(2):122-33. Mefloquine is an orally administered blood schizontocide for the chemoprophylaxis of malaria in nonimmune travelers. New pharmacokinetic data has shown that food increases the bioavailability of mefloquine. Steady-state pharmacokinetics of weekly prophylaxis in long term travelers have shown that toxic accumulation does not occur and that weekly dosing is associated with protective levels of the drug. The pharmacokinetics of mefloquine are highly stereospecific and all pharmacokinetic parameters, except tmax are significantly different for the (+) and (-) enantiomers. Mefloquine and its metabolite are not appreciably removed by hemodialysis. Steady-state levels of mefloquine can be attained in a reduced time frame of 4 days compared to 7-9 weeks using a loading dose strategy of 250 mg mefloquine daily for 3 days followed thereafter by weekly mefloquine dosage. This strategy, is however, associated with a higher incidence of an adverse event (AE). Cumulative evidence suggests a high protective efficacy of mefloquine (>91%) in nonimmune travelers to areas of chloroquine resistant Plasmodium falciparum (CRPF) except for clearly defined regions of multi-drug resistance. Reports from sub-Saharan Africa indicate a low but increasing level of resistance to this drug. Mefloquine resistance is associated with halofantrine and quinine resistance but not with chloroquine resistance. Penfluridol has been shown to reverse P. falciparum mefloquine resistance in vitro. There is some controversy regarding the tolerabilty of mefloquine for malaria chemoprophylaxis. A review of the studies conducted during 1992-1998 shows that in the reporting of any AE the incidence lies in the range (12-90%) and where there is a comparator, is equivalent to the incidence reported for almost all alternative regimens. When some measure of subjective severity is applied to the rating of AE, it appears that 11-17% of travelers are, to some extent, incapacitated by AE. Major studies and worldwide monitoring have shown that serious events are rare. A recent meta-analysis showed that rates of withdrawal and overall incidence of AE with mefloquine were not significantly higher than those observed with comparator regimens except that mefloquine was more likely to cause insomnia and fatigue. Withdrawals in mefloquine arms were higher than in placebo arms. No performance deficit or functional impairment was observed in five clinical toxicity studies of mefloquine prophylaxis, including a study of driving performance. There is limited data regarding use of mefloquine in pregnancy. Early animal studies have documented teratogenic and embryotoxic effects associated with the use of high dose mefloquine. Two studies have shown a relatively high incidence of spontaneous abortions in mefloquine users. Cumulative evidence, however, is reassuring and has led the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) to sanction the use of mefloquine in pregnant women during the second and third trimesters. In conclusion, mefloquine prophylaxis is recommended for travelers to high risk areas of chloroquine resistant Plasmodium falciparum. The risk of malarial infection and the proven efficacy of mefloquine to prevent malaria should be weighed against the risk of drug associated adverse events.

Azithromycin

1. Andersen SL et al. Successful double-blinded, randomized, placebo-controlled field trial of azithromycin and doxycycline as prphyalxis for malaria in Western Kenya. Clin Inf Dis 1998;26:146-50

2. Taylor WR, Richie TL, Fryauff DJ, et al. Malaria prophylaxis using azithromycin: a double-blind, placebo-controlled trial in Irian Jaya, Indonesia. Clin Infect Dis 1999 Jan;28(1):74-81

Clindamycin

1. Kremsner PG. Clindamycin in malaria treatment. J Antimicrobial Chemotherapy 1990;25:9-14

Quinine

1. Kremsner et al. Clindamycin in combination with chloroquine or quinine is an effective therapy for uncomplicated plasmodium falciparum malaria in children from Gabon. J Inf Dis 1994;169:467-70

2. McGready R, Cho T, Hkirijaroen L, Simpson J, Chongsuphajaisiddhi T, White NJ, Nosten F. Quinine and mefloquine in the treatment of multidrug-resistant Plasmodium falciparum malaria in pregnancy. Annals of Tropical Medicine and Parasitology 1998 Sep;92(6):643-53. Between 1991 and 1996, 372 pregnant women with uncomplicated, multidrug-resistant Plasmodium falciparum malaria, living on the western border of Thailand, were treated with either mefloquine (N = 194), quinine (N = 93) or both drugs (N = 85). Antimalarial treatment was generally well tolerated; the most common side-effects were dizziness (42%) and tinnitus (35%) following quinine, and anorexia (23%) and dizziness (36%) following mefloquine. In the patients treated for primary infections with melfloquine, 6% failed to clear their parasitaemia by day 7 and 28% failed by day 42. The corresponding figures for quinine were 4% and 23%, respectively. The failure rates in the 117 women treated for recrudescent infections were higher, the increase being significant for quinine (38%; P = 0.03) but not for mefloquine (37%). The percentage of pregnant women who had patent gametocytaemia on presentation ranged from 4%-19%. Over 50% of the patients were anaemic (haematocrit < 30%) on presentation and 52% of those not anaemic on enrolment developed anaemia during follow-up. Mefloquine and quinine, the only antimalarials generally available for the treatment of highly drug-resistant P. falciparum in pregnancy, give unsatisfactory treatment responses when used as single agents. New, safe and effective regimens are needed for the treatment of pregnant women with multidrug-resistant falciparum malaria.

3. McGready R, Thwai KL, Cho T, et al. The effects of quinine and chloroquine antimalarial treatments in the first trimester of pregnancy. Trans R Soc Trop Med Hyg 2002 Mar-Apr;96(2):180-4. Quinine (n = 246) was used to treat uncomplicated Plasmodium falciparum and chloroquine (n = 130) was used to treat P. vivax, in a total of 376 episodes of malaria in the first trimester of pregnancy, in 300 Karen women (Thailand, 1995-2000). Parasites were still present on day 6 or 7 in 4.7% (11/234) of episodes treated with quinine. The overall 28 day parasite reappearance rate following quinine was 28.7% (60/209) for primary treatments and 44% (11/25) for re-treatments. Quinine treatment resulted in a high rate of gametocyte carriage: person-gametocyte-weeks = 42.5 (95% CI 27.8-62.1) per 1000 woman-weeks. For P. vivax, the reappearance rate for all episodes by day 28 was 4.5% (5/111). Significantly more women complained of tinnitus following quinine treatment compared to on admission: 64.5% (78/121) vs 31.6% (59/187), P < 0.001. Using survival analysis, the community rate of spontaneous abortion in women who never had malaria in pregnancy, 17.8% (16.5-19.0), did not differ significantly from rates in women treated with quinine: 22.9% (95% CI 15.5-30.3), or chloroquine: 18.3% (95% CI 9.3-27.3), P = 0.42. Pregnancies exposed to quinine or chloroquine and carried to term did not have increased rates of congenital abnormality, stillbirth or low birthweight. These results suggest that therapeutic doses of quinine and chloroquine are safe to use in the first trimester of pregnancy.

Artemisinin

1. McGready R, Cho T, Samuel, et al. Randomized comparison of quinine-clindamycin versus artesunate in the treatment of falciparum malaria in pregnancy. Trans R Soc Trop Med Hyg 2001;95:651-6. In areas where multidrug-resistant Plasmodium falciparum (MDR-Pf) is prevalent, only quinine is known to be safe and effective in pregnant women. On the western border of Thailand, 7 days of supervised quinine (30 mg/kg daily) cures two-thirds of P. falciparum-infected women in the 2nd and 3rd trimesters of pregnancy. Artesunate is effective against MDR-Pf and the limited data on its use in pregnancy suggest it is safe. An open randomized comparison of supervised quinine (10 mg salt/kg every 8 h) in combination with clindamycin (5 mg/kg every 8 h) for 7 days (QC7) versus artesunate 2 mg/kg per day for 7 days (A7) was conducted in 1997-2000 in 129 Karen women with acute uncomplicated falciparum malaria in the 2nd or 3rd trimesters of pregnancy. There was no difference in the day-42 cure rates between the QC7 (n = 65) and A7 (n = 64) regimens with an efficacy of 100% in both, confirmed by parasite genotyping. The A7 regimen was also associated with less gametocyte carriage; the average person-gametocyte-weeks for A7 was 3 (95% CI 0-19) and for QC7 was 39 (95% CI 21-66) per 1000 person-weeks, respectively (P < 0.01). There was no difference in gastrointestinal symptoms between the groups but there was significantly more tinnitus in the QC7 group compared to the A7 group (44.9% vs 8.9%; RR 5.1; 95% CI 1.9-13.5; P < 0.001). The favourable results with quinine-clindamycin mean that there is a useful back-up treatment for women with falciparum malaria who experience quinine and artesunate failures in pregnancy. Adherence to the 7-day regimen and cost (US$18.50 per treatment) are likely to be the main obstacles to this regimen.

2. McGready R et al. Artemisinin derivatives in the treatment of falciparum malaria in pregnancy. Transactions of the Royal Society of Tropical Medicine and Hygiene, 1998, 92:430–433. An artemisinin derivative (artesunate or artemether) was used for the treatment of multidrug-resistant Plasmodium falciparum malaria in 83 Karen pregnant women in Thailand; 55 women were treated for recrudescent infection following quinine or mefloquine, 12 for uncomplicated hyperparasitaemic episodes, and 16 had not declared their pregnancy when treated. The women were followed weekly until delivery. Artesunate and artemether were well tolerated and there was no drug-related adverse effect. Recrudescence within 42 d occurred in 16% of the treated episodes. Overall 73 pregnancies (88%) resulted in live births, 3 (4%) in abortions and 2 (3%) in still births, and 5 women were lost to follow-up before delivery. There was no congenital abnormality in any of the newborn children, and the 46 children followed for more than one year all developed normally.

3. McGready R, Cho T, et al. Artemisinin antimalarials in pregnancy: a prospective treatment study of 539 episodes of multidrug-resistant Plasmodium falciparum. Clin Infect Dis 2001 Dec 15;33(12):2009-16 McGready R, Cho T, Samuel, et al. The emergence and spread of multidrug-resistant Plasmodium falciparum compromises the treatment of malaria, especially during pregnancy, where the choice of antimalarials is already limited. Artesunate (n=528) or artemether (n=11) was used to treat 539 episodes of acute P. falciparum malaria in 461 pregnant women, including 44 first-trimester episodes. Most patients (310 [57.5%]) received re-treatments after earlier treatment with quinine or mefloquine. By use of survival analysis, the cumulative artemisinin failure rate for primary infections was 6.6% (95% confidence interval, 1.0-12.3), compared with the re-treatment failure rate of 21.7% (95% confidence interval, 15.4-28.0; P=.004). The artemisinins were well tolerated with no evidence of adverse effects. Birth outcomes did not differ significantly to community rates for abortion, stillbirth, congenital abnormality, and mean gestation at delivery. These results are reassuring, but further information about the safety of these valuable antimalarials in pregnancy is needed.

4. McGready R, Brockman A, Cho T Randomized comparison of quinine-clindamycin versus artesunate in the treatment of falciparum malaria in pregnancy. Trans R Soc Trop Med Hyg 2001;95:651-6. Since no effective malaria prevention measures have been identified for pregnant women living on the western border of Thailand, prompt diagnosis and efficient treatment are paramount, although drug resistance in Plasmodium falciparum has narrowed the treatment options. An open randomized comparison of supervised quinine (10 mg salt/kg every 8 h) for 7 days (Q7) versus mefloquine 25 mg base/kg (total dose) plus artesunate 4 mg/kg per day for 3 days (MAS3) was conducted in 1995-97 in 108 Karen women with acute uncomplicated falciparum malaria in the second or third trimesters of pregnancy. The MAS3 regimen was more effective than the Q7 regimen: day 63 cure rates were 98.2% (95% CI 94.7-100) (n = 65) for MAS3 and 67.0% (95% CI 43x3-90x8) (n = 41) for Q7, P = 0x001. The MAS3 regimen was also associated with less gametocyte carriage; the average person-gametocyte-weeks for MAS3 was 2.3 (95% CI 0-11) and for Q7 was 46x9 (95% CI 26-78) per 1000 person-weeks, respectively (P < 0.001). MAS3 was significantly better tolerated. These evident advantages must be balanced against a possible increased risk of stillbirth with the use of mefloquine in pregnancy. Further randomized studies assessing the safety and efficacy of other artemisinin-containing combination regimens in pregnancy are needed urgently.

5. McGready R, Brockman A, Cho T, et al. Randomized comparison of mefloquine-artesunate versus quinine in the treatment of multidrug-resistant falciparum malaria in pregnancy. Trans R Soc Trop Med Hyg 2000;94:689-93. Since no effective malaria prevention measures have been identified for pregnant women living on the western border of Thailand, prompt diagnosis and efficient treatment are paramount, although drug resistance in Plasmodium falciparum has narrowed the treatment options. An open randomized comparison of supervised quinine (10 mg salt/kg every 8 h) for 7 days (Q7) versus mefloquine 25 mg base/kg (total dose) plus artesunate 4 mg/kg per day for 3 days (MAS3) was conducted in 1995-97 in 108 Karen women with acute uncomplicated falciparum malaria in the second or third trimesters of pregnancy. The MAS3 regimen was more effective than the Q7 regimen: day 63 cure rates were 98.2% (95% CI 94.7-100) (n = 65) for MAS3 and 67.0% (95% CI 43x3-90x8) (n = 41) for Q7, P = 0x001. The MAS3 regimen was also associated with less gametocyte carriage; the average person-gametocyte-weeks for MAS3 was 2.3 (95% CI 0-11) and for Q7 was 46x9 (95% CI 26-78) per 1000 person-weeks, respectively (P < 0.001). MAS3 was significantly better tolerated. These evident advantages must be balanced against a possible increased risk of stillbirth with the use of mefloquine in pregnancy. Further randomized studies assessing the safety and efficacy of other artemisinin-containing combination regimens in pregnancy are needed urgently.

6. Nosten F, van Vugt M, Price R, et al. Effects of artesunate-mefloquine combination on incidence of Plasmodium falciparum malaria and mefloquine resistance in western Thailand: a prospective study. Lancet 2000 Jul 22;356(9226):297-302. BACKGROUND: Worsening drug resistance in Plasmodium falciparum malaria is a major threat to health in tropical countries. We did a prospective study of malaria incidence and treatment in an area of highly multidrug-resistant P. falciparum malaria. METHODS: We assessed incidence of P. falciparum malaria and the in-vivo responses to mefloquine treatment over 13 years in two large camps for displaced Karen people on the northwest border of Thailand. During this time, the standard mefloquine dose was first increased, and then combined artesunate and mefloquine was introduced as first-line treatment for uncomplicated P. falciparum malaria. FINDINGS: Early detection and treatment controlled P. falciparum malaria initially while mefloquine was effective (cure rate with mefloquine [15 mg/kg] and sulphadoxine-pyrimethamine in 1985, 98% [95% CI 97-100]), but as mefloquine resistance developed, the cure rate fell (71% [67-77] in 1990). A similar pattern was seen for high-dose (25 mg/kg) mefloquine monotherapy from 1990-94. Since the general deployment of the artesunate-mefloquine combination in 1994, the cure rate increased again to almost 100% from 1998 onwards, and there has been a sustained decline in the incidence of P. falciparum malaria in the study area. In-vitro susceptibility of P. falciparum to mefloquine has improved significantly (p=0.003). INTERPRETATION: In this area of low malaria transmission, early diagnosis and treatment with combined artesunate and mefloquine has reduced the incidence of P. falciparum malaria and halted the progression of mefloquine resistance. We recommend that antimalarial drugs should be combined with artemisinin or a derivative to protect them against resistance.

7. Deen JL, von Seidlein L, Pinder M, et al. The safety of the combination artesunate and pyrimethamine-sulfadoxine given during pregnancy. Trans R Soc Trop Med Hyg 2001 95:424-8. Malaria during pregnancy is associated with an increased risk of severe anaemia and low-birthweight babies. Effective intermittent therapy with pyrimethamine-sulfadoxine (PSD) decreases parasitaemia and severe anaemia and improves birthweight in areas where Plasmodium falciparum is sensitive to this drug. Increasing resistance to PSD is a concern and alternative antimalarial regimens during pregnancy are needed. Artesunate with PSD is a promising antimalarial combination but few data are available on the safety of artemisinins when taken during pregnancy. Outcome of pregnancy was evaluated for 287 women in The Gambia who were exposed in June 1999 to a single dose of the combination artesunate and PSD during a mass drug administration and 172 women who were not exposed. Women who received placebo (40) and those who did not participate in the mass drug administration (132) comprised the non-exposed group. There was no difference in the proportion of abortions, stillbirths, or infant deaths among those exposed or not exposed to the drugs. The mean weight of 18 infants born to mothers who had received artesunate and PSD during the third trimester was 3.10 kg compared to a mean weight of 2.62 kg of the 10 infants of untreated mothers (adjusted P value = 0.05). We found no evidence of a teratogenic or otherwise harmful effect of gestational exposure to artesunate and PSD. Treatment of a self-selected group of pregnant women with PSD and artesunate during pregnancy was associated with a greater birthweight, which may have resulted from clearance of malaria parasites. However, the influence of confounding factors cannot be excluded.

8. The use of artemisinin & its derivatives as anti-malarial drugs. WHO/MAL/ 98.1086 p.20(Geneva 10-12 June 1998); report of a joint CTD/DMP/TDR informal consultation (distr. Limited)

9. McGready R, Cho T, Cho JJ, et al. Artemisinin derivatives in the treatment of falciparum malaria in pregnancy. Trans R Soc Trop Med Hyg 1998 Jul-Aug;92(4):430-3. An artemisinin derivative (artesunate or artemether) was used for the treatment of multidrug-resistant Plasmodium falciparum malaria in 83 Karen pregnant women in Thailand; 55 women were treated for recrudescent infection following quinine or mefloquine, 12 for uncomplicated hyperparasitaemic episodes, and 16 had not declared their pregnancy when treated. The women were followed weekly until delivery. Artesunate and artemether were well tolerated and there was no drug-related adverse effect. Recrudescence within 42 d occurred in 16% of the treated episodes. Overall 73 pregnancies (88%) resulted in live births, 3 (4%) in abortions and 2 (3%) in still births, and 5 women were lost to follow-up before delivery. There was no congenital abnormality in any of the newborn children, and the 46 children followed for more than one year all developed normally.

Atovoquone/proguanil

1. Wangboonskul J, White NJ, Nosten F, et al. Single dose pharmacokinetics of proguanil and its metabolites in pregnancy. Eur J Clin Pharmacol 1993;44(3):247-51. Plasma and whole blood concentrations of proguanil, its active metabolite cycloguanil, and the inactive metabolite 4-chlorophenyl-biguanide, were measured by HPLC in 10 healthy Karen women in the last trimester of pregnancy, following a 200 mg single oral dose of proguanil. Four of these women were restudied 2 months after delivery. The pharmacokinetic properties of proguanil were similar during and after pregnancy. Median peak plasma concentrations of proguanil during pregnancy and following delivery were 212 and 215 ng.ml-1, and occurred at 4.5 and 5 h, respectively. Mean plasma AUC values for proguanil during and following pregnancy were 94 and 98 ng.h.ml-1.kg-1, respectively. Corresponding whole blood AUC values were 361 and 396 ng.h.ml-1.kg-1. The mean elimination half lives and mean residence times of proguanil in plasma and whole blood were 12.3 and 19.6 h and 13.8 and 20.7 h respectively during pregnancy. Following pregnancy these values were 17.1 and 19.7 h for plasma and 19.7 h and 20.2 h for whole blood respectively. Mean peak plasma and whole blood concentrations of cycloguanil following pregnancy were 25 and 22 ng.ml-1 respectively. During pregnancy peak cycloguanil concentrations in both plasma and whole blood were markedly lower, 13 and 12 ng ml-1, respectively. Two pregnant women (neither of whom were restudied) were probably poor metabolisers of proguanil. The mean ratio of proguanil to cycloguanil plasma AUC was 16.7 in the third trimester of pregnancy and 7.8 following pregnancy, compared with less than 5 in previously reported studies.(ABSTRACT TRUNCATED AT 250 WORDS)

2. McGready R, Ashley EA, Moo E, et al. A randomized comparison of artesunate-atovaquone-proguanil versus quinine in treatment for uncomplicated falciparum malaria during pregnancy. J Infect Dis. 2005 Sep 1;192(5):846-53. Epub 2005 Jul 27. CONCLUSION: AAP is a well-tolerated, effective, practical, but expensive treatment for multidrug-resistant falciparum malaria during the second or third trimesters of pregnancy. Despite the small number of subjects, our results add to the growing body of evidence that AAP is safe for the mother and the fetus.