MHRA highlights drug interaction risk for hepatitis C antivirals

INR should be monitored closely in hepatitis C patients co-prescribed antivirals and vitamin K antagonists, the MHRA has advised.

INR values may fluctuate when vitamin K antagonists are co-administered with hepatitis C antivirals.  | SCIENCE PHOTO LIBRARY
INR values may fluctuate when vitamin K antagonists are co-administered with hepatitis C antivirals. | SCIENCE PHOTO LIBRARY

The MHRA advice, published in its latest Drug Safety Update, follows a Europe-wide review of the use of concomitant vitamin K antagonists (eg, warfarin) and direct-acting antivirals for hepatitis C, which reported that changes in liver function secondary to treatment with hepatitis C antivirals may affect the efficacy of vitamin K antagonists resulting in fluctutations in INR values.

The MHRA states that the benefits of treatment with direct-acting antivirals for chronic hepatitis C continue to outweigh the risks of an interaction with vitamin K antagonists. However, INR should be monitored closely in patients co-prescribed these medicines and anticoagulant therapy adjusted if necessary.

Patients should be advised to inform their doctor or pharmacist if they are taking warfarin or other similar medicines and are prescribed direct-acting antivirals. Those who are taking a vitamin K antagonist should be informed that they may need more regular blood tests during treatment for hepatitis C.

Direct-acting antivirals for the treatment of chronic hepatitis C include: daclatasvir (Daklinza), dasabuvir (Exviera), ombitasvir/paritaprevir/ritonavir (Viekirax), sofosbuvir (Sovaldi), sofosbuvir/ledipasvir (Harvoni), sofosbuvir/velpatasvir (Epclusa) and simeprevir (Olysio).


Register or Subscribe to MIMS

GPs can get MIMS print & online and GPonline for free when they register online – take 2 minutes, and make sure you get your free MIMS access! If you're not a GP, you can subscribe to MIMS for full access.

Register or subscribe

MIMS bulletins

News and updates straight to your inbox.

Prescribing Update: Fortnightly news bulletin
Alert:
Urgent prescribing updates
Spotlight: Disease-themed monthly round-up

Sign me up

MIMS Dermatology

Read the latest issue online exclusively on MIMS Learning.

Read MIMS Dermatology

Mobile apps

MIMS: access the full drug database and quick-reference tables on the go

MIMS Diagnosis and Management: concise information on signs and symptoms, investigations and diseases

Promo Image

Clinical calculators

Handy calculators and conversions for primary care.