Dutch clinicians in a recent study apparently did a good job of negotiating potential harmful drug-drug interactions (DDIs) between antiretroviral (ARV) treatments for HIV and direct-acting antiviral (DAA) treatments for hepatitis C virus (HCV) among those coinfected with both viruses. However, researchers found that these health care providers could do better at preventing ill-advised, potentially harmful pairings of DAAs and non-HIV medications.

Researchers analyzed data from a Dutch cohort of 423 HIV/HCV-coinfected individuals who were treated with DAAs. Ninety-nine percent were on ARVs, and 59 percent were taking non-ARV medications as they prepared to undergo DAA treatment.

The study authors looked at the medications that the participants were taking before starting DAAs and categorized them as posing no expected threat of interaction with DAAs, posing a potential threat of an interaction (considered a category 2 DDI) or being ill advised because of potential harmful interactions (a category 3 DDI).

Before starting treatment for hep C, 20 percent of the participants were taking non-ARV medications in category 2 or 3 of DDIs; of these, only 20 percent discontinued those drugs before starting DAAs, including one third of those taking drugs in category 3.

Forty-seven percent of those on ARVs had a category 2 or 3 DDI for their HIV meds. Of those in this group with a category 2 DDI, a bit more than half switched their ARVs; of those with a category 3 DDI, 98 percent switched their ARVs.

Eighty-seven percent of the group was cured of hep C.

“Savvy patients should be aware of the multitude of potential drug interactions surrounding current HIV and hep C therapies,” says Tony Mills, MD, chief executive officer of the Southern California Men’s Medical Group in Los Angeles. “Discuss these possible conflicts with your doctor to make sure you are both aware of potential pitfalls and that the effectiveness of the treatments are assured.”