Different Drug-Alcohol Interactions Seen Among Three Antiretroviral Drugs

People with HIV often consume alcohol, and sometimes at unhealthy levels. Since alcohol use is a risk factor for HIV seroconversion and disease progression, clinicians and patients often have questions about whether they can drink — even socially — while they are being treated with antiretroviral therapy (ART). Patients who are unclear about drug-alcohol interactions may skip doses or become non-adherent to ART for days while they drink, and ART resistance becomes a concern whenever patients skip doses.

As a result, researchers are increasingly attempting to determine if specific drugs interact with alcohol and alter metabolism or side effects, and now, physicians have definitive answers for three ARTs.

Researchers at the University of California San Francisco (UCSF) studied the potential interaction between alcohol and the entry inhibitor maraviroc. Marketed as Selzentry, maraviroc is the only approved cellular cytokine-receptor antagonist, and developing resistance to the drug eliminates its treatment mechanism.

The double-blind, placebo-controlled study enrolled 10 participants who were randomly assigned to either oral alcohol (1 g/kg to produce moderate intoxication) or alcohol placebo, followed by maraviroc administration at standard clinical doses of 150 mg twice daily for seven days. The researchers found maraviroc pharmacokinetics were unaffected by alcohol administration, although blood alcohol concentrations (BAC) increased 12 percent over 8 hours, which may boost the risk of alcohol-related toxicities and adverse outcomes in patient who consume alcohol.

The UCSF research group then looked at the potential for ritonavir and efavirenz to interact with alcohol. Using a similar study design, the researchers found that ritonavir or efavirenz pharmacokinetics were also unaffected by alcohol. But unlike maraviroc's outcome, the patients’ BAC was lower, indicating that alcohol’s bioavailability decreased. Still, despite their lower BAC, patients who consumed alcohol while taking efavirenz did not experience changes in intoxication or drowsiness.