18 THERAPY

Managing opportunNic infedions ~withmv

Atovaquone - an alternative for PCP Atovaquone is a useful alternative for the

treatment of Pneumocystis carinii pneumonia (PCP) in patients with AIDS who are unresponsive or intolerant to cotrimoxazole [trimethoprim/ sulfamethoxazole] .

Despite being less effective than cotrimoxazole for the treatment of PCP. atovaquone was associated with less treatment-limiting adverse effects in a US study. The rate of nonresponders was higher in the atovaquone than in the cotrimoxazole groups (20 vs 7%. respectively). However. adverse effects leading to drug withdrawal were significantly less common in the atovaquone group (7 vs 20%).

Patients with mild to moderate PCP received atovaquone 750mg tid (n = 138) or cotrimoxazole 320/1600mg tid (146) for 21 days. Hughes W. Lcoung G. Kramer F, Bozzeue SA, Safrin S, et aI. Comparison of atovaquooe (566C80) with trimethoprim-sulfamethoxazole to treat

Pnewnocystis carinii pneumonia in patients with AIDS. New England Journal of Medicine 328: IS21 -IS27, 27 May 1993 ... ,...,.

• Edilorild colftllUlII: Atovaquone {566CSOj is a hydroxynaphthoquinone protozoan electron transpon inhibitor, developed by WeI/come as an anti protozoal agent. It is approved in the US and CONJdafor PCP treatment and is due for approval in Europe early in 1994 for both PCP and toxoplasmosis. The agent is also currently undergoing phase II trials in the UK and Thailand as an antimalarial.

Combination prevents tox~ Dapsone + pyrimethamine will be the regimen of

choice for preventing toxoplasmosis in HIV positive patients until less toxic regimens are proven effective. The combination also seems to be an 'attractive alternative' to aerosolised pentamidine for the primary prevention of Pneumocystis carinii pneumonia (PCP). despite being less well tolerated. conclude French researchers.

The researchers found that the incidence of toxoplasmosis was lower in HIV positive patients receiving primary prophylaxis with dapsone 50 mg/day + pyrimethamine 50 mg/week (n = 173) compared with those receiving aerosolised pentamidine 300 mg/month (176; relative risk 1.81). However, prevention of first episodes of PCP and survival rates were similar between the 2 treatment regimens. Patients were followed for a median of 539 days.

When the 262 patients who were seropositive for Toxoplasma gondii at baseline were analysed separately, the relative risk of toxoplasmosis was 2.37 times higher in pentamidine than in dapsone­pyrimethamine recipients.

Primary prophylaxis against toxoplasmosis has not yet been recommended in HIV positive patients. However, in view of the marked increase in the incidence of this opportunistic infection together with the associated serious morbidity and sequelae,

5 Jun 11183 INPHARMA·

primary prophylaxis is warranted, say the researchers. Girard P-M, Landman R. Gaudebout C. Olivares R. Saimot AG. et aI. Dapsone-pyrimethamine compared with aerosolized pentamidine as primary prophylaxis against Pnewnocystis carinii pneumonia and toxoplasmosis in HIV infection. New England Journal of Medicine 328: ISI4-1520, 27 May 1993 ""99657

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