Adverse drug reactions (ADRs) in patients with HIV infection. A prospective study

A prospective drug surveillance method was used to monitor 50 ambulatory patients with HIV infection, who were controlled in the Sexual Transmission Disease Service at Dr. Sotero del Río Hospital (Santiago, Chile). The aim of this work was to characterize and study the frequency, characteristics, and associated factors of the ADRs in HIV-infected patients.

Patients were interrogated once or twice a month by a clinical pharmacist, who consigned data concerning the drug prescribed by the physician, drug-related signs and symptoms, and the laboratory's parameters as renal, hepatic, hematological function, and biochemical test. The ADR probability was assessed for an algorithm.

The frequency of adverse drug reactions found in the group of patients studied was 32.0%. The dermatological, hepatic, and hematological systems were the most affected by adverse drug reactions. Trimethroprim-sulfamethoxazole and zidovudine were the drugs mainly associated with ADRs. Patients with lymphocytes CD4+ count of 200 or less, presented a higher frequency of ADRs. 48.5% of ADRs were classified as probable. Severe reactions were found in 18.5% of the patients, and moderate in 70.4%. 50% of patients with ADRs needed the withdrawal of the implicated drug, and an 18.5% dose decreased. 63% of the ADRs were dose-independent.

There was a higher frequency of ADRs in those patients with multiple-drug therapy, but the frequency of ADR was not associated with age, gender, or hematological test.