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Biomedical subjects

R McGready

Publications and source records attributed to R McGready.

30 records · Page 2Linked to original sources

Adverse effects in patients with acute falciparum malaria treated with artemisinin derivatives.

In prospective studies of acute uncomplicated, multidrug-resistant falciparum malaria on the western border of Thailand, the oral artemisinin derivatives were used alone in the treatment of 836 patients (artesunate 630, artemether 206), were combined with mefloquine (15-25 mg base/kg) in 2,826 patients, and mefloquine alone was used in 1,303 patients. The combined regimens of mefloquine plus an artemisinin derivative were associated with more side effects than those with an artemisinin derivative alone; acute nausea (31% versus 16%), vomiting (24% versus 11%), anorexia (51% versus 34%), and dizziness (47% versus 15%) (P < 0.001). Oral artesunate and artemether alone were very well tolerated. There was no difference in the incidence of possible adverse effects between the two drugs, and no evidence that either derivative caused allergic reactions, neurologic or psychiatric reactions, or cardiovascular or dermatologic toxicity. Blackwater fever occurred in three patients treated with mefloquine plus artesunate regimens. Oral artesunate and artemether are safe and well tolerated antimalarial drugs.

Acute Disease↗

Quinine and mefloquine in the treatment of multidrug-resistant Plasmodium falciparum malaria in pregnancy.

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.

Adolescent↗

Artemether-lumefantrine for the treatment of multidrug-resistant falciparum malaria.

The efficacy and safety of the 6-dose regimen of artemether-lumefantrine were assessed in an open randomized trial in children and adults presenting with acute, uncomplicated Plasmodium falciparum malaria in Thailand between November 1997 and March 1998. 200 patients were enrolled in 2 centres: 150 received artemether-lumefantrine (i.e., a median total dose of 9.6 mg/kg [interquartile range 8.7-10.7] and 57.9 mg/kg of lumefantrine [52.4-64.0]) and 50 the standard combination of artesunate (12 mg/kg over 3 d) and mefloquine (25 mg/kg). All patients had rapid initial clinical and parasitological responses. The 28 d cure rates were high: 97.7% (95% confidence interval [95% CI] 93.5-99.5%) for artemether-lumefantrine and 100% (95% CI 92.5-100%) for artesunate-mefloquine. The 6-dose regimen of artemether-lumefantrine was better tolerated than, and as effective as, artesunate-mefloquine, the current standard treatment in this area of multidrug-resistant P. falciparum malaria.

Adolescent↗

Randomized comparison of mefloquine-artesunate versus quinine in the treatment of multidrug-resistant falciparum malaria in pregnancy.

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.

Adolescent↗

Randomized comparison of quinine-clindamycin versus artesunate in the treatment of falciparum malaria in pregnancy.

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.

Adolescent↗

Artemisinin derivatives in the treatment of falciparum malaria in pregnancy.

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.

Adolescent↗

Treatment of vivax malaria on the western border of Thailand.

The efficacy of chloroquine (25 mg base/kg over 3 days) in Plasmodium vivax malaria was evaluated in 1995/96 in 342 patients living in an endemic area on the western border of Thailand. Clearance of fever and parasites was obtained within 2 days in > 95% of the patients, and all were aparasitaemic by day 4. Reappearance of P. vivax occurred in 1 patient on day 21 and in 8 by day 28, giving a 28-day cure rate of 97% [95% confidence interval (CI) 95-99%]. By day 63, the relapse/re-infection rate was 63% (95% CI 57-69%). Most reappearances of parasitaemia (85%; 121/143) were symptomatic. These patients were retreated either with chloroquine alone (n = 70) or with chloroquine and primaquine (0.25 mg/kg daily for 14 days) (n = 43). Only 1 patient (in the chloroquine-only group) had prolonged parasite clearance (D8) and he developed recurrent P. vivax by day 21 suggesting possible recrudescence. The addition of primaquine to chloroquine reduced the risk of having a third vivax episode within 2 months by 96% (95% CI 83-99%). This resulted in a significantly higher haematocrit at day 42 despite a greater decrease in haematocrit during the first week of treatment with chloroquine-primaquine (P = 0.04). Chloroquine remains highly effective on the western border of Thailand and the use of strictly supervised primaquine effectively prevents relapse. The introduction of primaquine on a large scale in an endemic area still requires a long-term risk-benefit assessment which must take into account potential toxicity, low compliance and reductions in the incidence and severity of P. falciparum infections by co-existent P. vivax.

Adolescent↗