View Table: Mechanisms of Drug Interactions

A recent letter to the editor of the Annals of Internal Medicine documented a single case of myopathy apparently due to an interaction between simvastatin (Zocor, and others) and green tea. Since it became available generically, simvastatin has surpassed atorvastatin (Lipitor) as the best selling statin. As such, it is probably the most common cause of statin-induced myopathy, which is often a result of drug interactions.

The FDA has approved Odefsey (Gilead), a once-daily, fixed-dose combination of the non-nucleoside reverse transcriptase inhibitor (NNRTI) rilpivirine and the nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) emtricitabine and tenofovir alafenamide, for initial treatment of HIV-1 infection in patients with HIV-1 RNA (viral load) ≤100,000 copies/mL or to replace a stable antiretroviral regimen in patients who have been virologically suppressed (viral load <50 copies/mL) for at least six months with no history of treatment failure.

View Table 3: Some Drug Interactions with DAAs for HCV Infection

The FDA has approved Viekira Pak (Abbvie), a fixed-dose combination of two new direct-acting antiviral agents (ombitasvir, paritaprevir) with the pharmacologic enhancer ritonavir in one tablet, co-packaged with a third new direct-acting antiviral agent (dasabuvir) in a second tablet, for oral treatment of chronic hepatitis C virus (HCV) genotype 1 infection. Genotype 1 is responsible for 70-80% of HCV infections in the US.

View the Expanded Table: Statins

A reader has questioned why the label for the COX-2 selective NSAID celecoxib (Celebrex, and generics), which contains a sulfonamide moiety, states that it is contraindicated for use in patients with an allergy to sulfonamides, while the labels of some other sulfonamide drugs recommend either caution or no precautions at all. The concept of cross-reactivity among sulfonamide drugs, particularly between antibacterial and nonantibacterial sulfonamides, has been controversial for many years.

The lipid-lowering drug rosuvastatin is now available in a sprinkle capsule formulation (Ezallor Sprinkle – Sun Pharma). Rosuvastatin tablets (Crestor, and generics) have been available since 2003.1,2The new formulation is being marketed specifically for residents of long-term care facilities who have difficulty swallowing. Ezallor Sprinkle capsules can be swallowed whole or opened and their contents sprinkled over applesauce or mixed with water for administration via nasogastric tube.For those long-term care residents who still have a reasonable indication for a statin but have difficulty...

The FDA has approved Mavyret (Abbvie) and Vosevi (Gilead), two new fixed-dose combinations of direct-acting antiviral (DAA) drugs, for treatment of chronic hepatitis C virus (HCV) infection caused by any of the six major HCV genotypes in patients without cirrhosis or with compensated cirrhosis. Both are approved for use in treatment-experienced patients. Mavyret is also approved for treatment-naive patients.

About 2.5 million persons in the US had hepatitis C between 2017 and 2020. Guidelines from the American Association for the Study of Liver Diseases (AASLD) and the Infectious Diseases Society of America (IDSA) on management of hepatitis C virus (HCV) infection were updated in 2023.