Pay attention when STARTING medications in patients taking hepatitis C antivirals

Delay any interacting medications that aren't critical, since hepatitis C treatment is usually just for 8 to 12 weeks....
Abdelwahab Ward, BS Pharm, PharmD

As a pharmacist, you'll face MANY potential drug interactions with hepatitis C antivirals (Epclusa [Qurevo], Mavyret, etc) even if you didn't start these medications. Interactions can lead to toxicity or treatment failure. And this can be an expensive mistake. Plus, hepatitis C medications may fly under the radar if the physician didn't prescribe them. Update the EHR with ALL medications (Rxs, OTCs, supplements, etc). 

     Delay any interacting medications that aren't critical, since hepatitis C treatment is usually just for 8 to 12 weeks. Keep in mind, interactions vary based on the hepatitis C antiviral, but a few should raise red flags.  

examples on drug interactions with hepatitis c antivirals
  • Acid reducers can decrease antiviral absorption. Be aware of dosing limits and spacing with PPIs, H2-blockers, and antacids. For example, usually avoid a PPI with Epclusa. Use an H2-blocker instead, dosed at the same time as Epclusa or 12 hours apart.
  • Statin side effects (myopathy, etc) may be more common since antivirals can increase statin levels. Generally, reduce or hold the statin with hepatitis C medications. For instance, limit rosuvastatin to 10 mg/day with Mavyret or Zepatier. Restart the original statin dose after stopping the antiviral.
  • Anticonvulsants can reduce antiviral levels. Avoid potent CYP3A4 inducers, such as phenytoin or carbamazepine, in combo with any hepatitis C antiviral. Think of valproic acid (Depakine) or lamotrigine (Lamictal) as an option.
  • Supplements should usually be avoided. For example, St. John's wort is a CYP450 inducer and lowers antiviral levels.

Evaluate drug interactions identified by the EHR or use the Univ of Liverpool's website at https://www.hep-druginteractions.org/. It's recognized as an authority by the Infectious Diseases Society of America.

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Abdelwahab Ward, BS Pharm, PharmD