[Show abstract][Hide abstract] ABSTRACT: This longitudinal study of travellers to Africa taking mefloquine (MQ) chemoprophylaxis aimed to quantify and assess non-serious adverse events (AE) occurring during short-term prophylaxis and relate these to concentrations of racemic MQ, its enantiomers and metabolite. A total of 420 volunteers (52% F) participated. AEs with some impact on activities were reported by 11.2% of participants including 7.9% of neurological/psychiatric symptoms. Women were more likely to report AEs (P=0.02). The standardized questionnaires used showed more pathological indicators in travellers who reported subjective AE with significantly more dizziness, distress, sleep disturbances and a high total mood disturbance (TMD) in the AE group. There was, however, no significant performance deficit in computerized psychomotor tests in those experiencing AE. Furthermore, no significant differences were observed in enantiomer ratios, metabolite concentrations, or racemic MQ levels in participants with or without AEs suggesting that these factors are not the main predictors of mefloquine intolerability.
Full-text · Article · Aug 2009 · Tropical Medicine & International Health
[Show abstract][Hide abstract] ABSTRACT: In murine malaria the addition of mefloquine to sulfadoxine/pyrimethamine has been shown to exert an additive effect and to significantly slow the emergence of resistance to the individual components. In a pilot study carried out in Gabon, a reduced dosage of the triple combination with a mean of 1 mg/kg of mefloquine/2 mg/kg of sulfadoxine/0.1 mg/kg of pyrimethamine (Fansimef; Roche, Basel, Switzerland) had previously been shown to achieve high cure rates in Plasmodium falciparum malaria. To evaluate the additive effect, a randomized, double-blind trial in school children with mild P. falciparum malaria was performed in Gabon. Two hundred thirty-one patients evaluated received a single dose of either the triple combination with a mean of 1.07 mg/kg of mefloquine/2.14 mg/kg of sulfadoxine/0.11 mg/kg of pyrimethamine (group MSP), or 1.07 mg/kg of mefloquine alone (group M), or 2.14 mg/kg of sulfadoxine/0.11 mg/kg of pyrimethamine alone (group SP). In the MSP group and the SP group, 67% and 69% of the patients were parasitologically cured, respectively, compared with only 13% in the M group (P < 0.001). A significantly higher parasitemia was found in the M group compared with the MSP group or the SP group on days 2 and 3 after the start of treatment. The high efficacy of the low dose sulfadoxine/pyrimethamine regimen was the most surprising finding of this study.
Preview · Article · Jun 1998 · The American journal of tropical medicine and hygiene
[Show abstract][Hide abstract] ABSTRACT: Background:To determine the relevance of drug interactions with co-medication for effectiveness and tolerability of antimalarial chemoprophylaxis.
Method: A database (MALPRO2) on travelers on their flight home from Africa to Europe between July 1988 and December 1991 was reanalyzed. It contains data on prophylaxis with mefloquine (n = 48,264), with chloroquine (6,752), with chloroquine plus proguanil (19,727), and with no prophylaxis (3,871). The comparison of rates of malaria incidence and adverse events (AEs) between users and nonusers of co-medication was expressed by relative risk (RR).
Results: Fifty-three percent of travelers (63% of females, 43% of males) used co-medication in all prophylaxis groups, with an average of 1.35 additional drugs per person and about two AEs reported per person. With the exception of antidiarrheals plus mefloquine, malaria incidence with co-medication was lower (RR = 0.8) than without co-medication. In all regimens, the proportion of travelers reporting AEs was about 1.5-fold with co-medication (p<.01);that reporting severe AEs was twice as high as compared to with no co-medication. Mefloquine AE rates for various classes of co-medication were similar to that of chloroquine, with highest AE and severity rates with neuropsychiatric drugs (excluding antiepileptics, RR = 1.9 and 2.9), and lowest rates with cardiovasculars (RR = 1.1 and 1.0). Various co-medications were used with different frequencies in males and females, and the latter reported more AEs.
Conclusion: These data suggest that co-medications commonly used by travelers have no significant clinical impact on safety and effectiveness of prophylaxis with mefloquine or chloroquine. Increased frequency and severity of AEs when using co-medication rather is explained by underlying illness.
Preview · Article · Oct 1997 · Journal of Travel Medicine
[Show abstract][Hide abstract] ABSTRACT: To assess the effect of food on the pharmacokinetics of the antimalarial mefloquine and its major plasma metabolite in healthy volunteers.
In an open, two-way cross-over study, 20 healthy male volunteers who had fasted overnight were randomised to receive a single oral dose of 750 mg mefloquine in the absence or presence of a standardised, high-fat breakfast, administered 30 min before drug administration. Blood samples were taken at specific times over an 8-week period. Plasma concentrations of mefloquine and its carboxylic acid metabolite were determined by high-performance liquid chromatography for pharmacokinetic evaluation.
The parameters Cmax and AUC of both mefloquine and its metabolite were significantly (P < 0.05) higher under post-prandial conditions than under fasting conditions (mefloquine: mean Cmax 1500 vs 868 micrograms.l-1, mean AUC 645 vs 461 mg l-1.h; metabolite: Cmax 1662 vs 1231 micrograms.l-1, AUC 1740 vs 1310 mg l-1.h). The intersubject variability in Cmax and AUC of mefloquine was less than 30% (coefficient of variation). The time to peak plasma concentration of mefloquine was significantly shorter after food intake (17 vs 36 h). Compared with absorption in volunteers who had fasted, food did not alter t1/2 (mefloquine and its metabolite) and tmax (metabolite).
Under the conditions of this study, food increases the rate and the extent of mefloquine absorption. It is reasonable to recommend that mefloquine be administered with food in travellers receiving chemoprophylaxis and in patients on recovery receiving curative treatment. In acutely ill patients, mefloquine should be taken as soon as possible and administration with or shortly after meals should be attempted as soon as feasible.
No preview · Article · Oct 1997 · European Journal of Clinical Pharmacology
[Show abstract][Hide abstract] ABSTRACT: Mefloquine and doxycycline are the two drugs recommended for prophylaxis of malaria for visitors to areas where Plasmodium falciparum is resistant to chloroquine.
To compare the efficacy and tolerability of mefloquine with those of doxycycline as prophylaxis for malaria.
Randomized, double-blind, placebo-controlled field trial of chemoprophylaxis of malaria.
Northeastern Irian Jaya, Indonesia.
204 Indonesian soldiers.
After radical curative treatment, participants were randomly assigned to receive 100 mg of doxycycline per day and mefloquine placebo; 250 mg of mefloquine per week (preceded by a loading dose of 250 mg/d for 3 days) and doxycycline placebo; or placebos for both drugs. Prophylaxis lasted approximately 13 weeks.
The primary end point for efficacy was the first occurrence of malaria, as documented by a positive malaria smear. Malaria smears were obtained weekly and when patients had symptoms suggesting malaria. Reported symptoms were recorded daily, and an exit study questionnaire was conducted.
In the placebo group, 53 of 69 soldiers developed malaria (9.1 person-years), resulting in an attack rate of 5.8 cases per person-year (95% CI, 4.3 to 7.7 cases per person-year). Plasmodium falciparum accounted for 57% of cases, and P. vivax accounted for 43% of cases. No malaria occurred in the 68 soldiers (16.9 person-years) in the mefloquine group; thus, the protective efficacy of mefloquine was 100% (CI, 96% to 100%). In the doxycycline group, P. falciparum malaria occurred in 1 of 67 soldiers (16.0 person-years), yielding a protective efficacy of 99% (CI, 94% to 100%). Both drugs were very well tolerated.
Mefloquine and doxycycline were both highly efficacious and well tolerated as prophylaxis of malaria in Indonesian soldiers.
No preview · Article · Jul 1997 · Annals of internal medicine
[Show abstract][Hide abstract] ABSTRACT: This longitudinal study of travellers to Africa taking mefloquine (MQ) chemoprophylaxis aimed to quantify and assess non-serious adverse events (AE) occurring during short-term prophylaxis and relate these to concentrations of racemic MQ, its enantiomers and metabolite. A total of 420 volunteers (52% F) participated. AEs with some impact on activities were reported by 11.2% of participants including 7.9% of neurological/psychiatric symptoms. Women were more likely to report AEs (P = 0.02). The standardized questionnaires used showed more pathological indicators in travellers who reported subjective AE with significantly more dizziness, distress, sleep disturbances and a high total mood disturbance (TMD) in the AE group. There was, however, no significant performance deficit in computerized psychomotor tests in those experiencing AE. Furthermore, no significant differences were observed in enantiomer ratios, metabolite concentrations, or racemic MQ levels in participants with or without AEs suggesting that these factors are not the main predictors of mefloquine intolerability.
No preview · Article · Sep 1996 · Tropical Medicine & International Health
[Show abstract][Hide abstract] ABSTRACT: In the absence of a suitable malaria case definition, reliable surveillance data on the impact of malaria are not available. Determinants of case loads, including population movements, environmental changes, lack of political commitment and resources, and resistance to antimalarials and residual insecticides, work towards global deterioration. Some 90% of the Plasmodium falciparum burden is carried by Africa south of the Sahara. There, in 1992, the number of children under five years of age and exposed to high risk was about 106 million. Assuming a malaria attack rate of 0.5-1.5 per child per year, and a case fatality rate of 2%, annual clinical cases and malaria deaths in this population alone come to 53-160 million and 1-3 million, respectively. Roche, a pharmaceutical company with major research efforts in tropical medicine, in collaboration with research centers and international institutions, has recently set up a tropical medicine unit that coordinates and concentrates corporate efforts in this field. The unit aims to make affordable and innovative products available which are effective against major tropical diseases. A commercial product of the unit is Lariam, a major antimalarial used alone or in simultaneous or sequential combinations. The single dose combination of Lariam plus Fansidar (Fansimef) is particularly useful for stand-by or emergency oral therapy. Artemisinine, or its derivatives, followed by one to two doses of Lariam are effective against severe and multiresistant P. falciparum malaria. A new Roche peroxide antimalarial is currently in phase II clinical trials. The unit is also involved in research and development of malaria sporozoite and asexual blood stage vaccine candidates.
No preview · Article · Oct 1993 · Tropical medicine and parasitology: official organ of Deutsche Tropenmedizinische Gesellschaft and of Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ)