People over 65 are at greater risk of drug-drug interactions between their medications and hepatitis C virus (HCV) treatments.

Publishing their findings in Alimentary Pharmacology and Therapeutics, researchers studied a group of 541 people treated for hep C in real-world settings. A total of 404 of the individuals were younger than 65, and 137 were 65 or older, of whom 41 were 75 or older.

Those with genotypes 1 or 4 of hep C received Harvoni (ledipasvir/sofosbuvir) with or without ribavirin, Daklinza (daclatasvir) and Sovaldi with or without ribavirin, or Olysio (simeprevir) and Sovaldi with or without ribavirin. Those with genotypes 2 or 3 received Daklinza and Sovaldi with or without ribavirin or Sovaldi and ribavirin.

Among those 65 and older and those younger than 65, a respective 98 percent and 91 percent achieved a sustained virologic response 12 weeks after completing therapy (SVR12, considered a cure). A respective 79 percent and 51 percent of the age groups took other medications; people with cirrhosis who were in the older group took the highest number of other drugs—a median of three drugs with a range between zero and 10.

Fifty-four percent of the older group had clinically significant drug-drug interactions between their medications and their hep C regimen compared with 28 percent of the younger set. A similar proportion— a respective 63 percent and 65 percent—experienced hep C treatment–related adverse health events,.

The study authors concluded that “with careful pre-treatment assessment of [non-hep C] medications, on-treatment monitoring or dose-modifications, significant [drug-drug interactions] and associated adverse events can be avoided.”

To read the study abstract, click here.