Trimethoprim-sulfamethoxazole compared with pentamidine for treatment of Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome. A prospective, noncrossover study.

STUDY OBJECTIVE

To ascertain the efficacy and toxicity of trimethoprim-sulfamethoxazole or pentamidine when either is given alone during the entire treatment period for Pneumocystis carinii pneumonia in patients with the acquired immunodeficiency syndrome (AIDS).

DESIGN

Prospective, randomized, noncrossover comparison of trimethoprim-sulfamethoxazole with pentamidine. Trimethoprim-sulfamethoxazole dosage was adjusted to maintain serum trimethoprim at 5 to 8 micrograms/mL. Pentamidine dosage was reduced by 30% to 50% for an absolute rise in serum creatinine of more than 88 mumol/L (1 mg/dL).

SETTING

Tertiary care hospital and AIDS clinic.

PATIENTS

Thirty-six patients were treated with trimethoprim-sulfamethoxazole and 34 with pentamidine. Pretreatment clinical features and laboratory test results were similar in the two groups.

MEASUREMENTS AND MAIN RESULTS

Thirty-six recipients of trimethoprim-sulfamethoxazole and 33 recipients of pentamidine completed therapy without crossover. Trimethoprim-sulfamethoxazole caused a rash (44%) and anemia (39%) more frequently (P less than or equal to 0.03, whereas pentamidine caused nephrotoxicity (64%), hypotension (27%), or hypoglycemia (21%) more frequently (P less than or equal to 0.01). The (A - a)DO2 improved by greater than 1.3 kPa (10 mmHg) 8 days earlier for trimethoprim-sulfamethoxazole recipients (95% CI for the difference in response, -1 to 17; P = 0.04). Thirty-one (86%) patients treated with trimethoprim-sulfamethoxazole and 20 (61%) with pentamidine survived and were without respiratory support at completion of treatment (95% CI for the difference in response, 5% to 45%; P = 0.03).

CONCLUSIONS

For most patients with AIDS and P. carinii pneumonia, successful treatment with a single agent is possible. Toxicity associated with the two standard treatments is rarely life-threatening and may be diminished if the trimethoprim-sulfamethoxazole dosage is modified by pharmacokinetic monitoring and the pentamidine dosage is reduced for nephrotoxicity. Oxygenation improved more quickly and survival was better with trimethoprim-sulfamethoxazole.