Date of report 21 Dec 2021
Reported case interaction between
Ritonavir and Daclatasvir
Ritonavir and Daclatasvir
Drugs suspected to be involved in the DDI-summary
Complete list of drugs taken by the patient
Metformin 850 mg OD, Sofosbuvir 300mg/Daclatasvir 60mg
Clinical case description
Social Hx: -Injecting drug user -Alcoholic -Heavy smoker
Medical Hx: -Living with HIV five years ago and on HAART -Diagnosed with DM type II 2 years ago and on Metformin Upon follow up after 4 weeks starting Hep C (Tab Sofosbuvir 300mg/Daclatasvir 60mg) :
1. Patient complaint easy feel tired and lose of appetite
2. Physical examination - jaundice
3. Elevated ALT (71 U/L), anaemia (HB = 9 d/L)
4. Blood glucose plasma level = 11 mm/mol
Suspect:
1. Toxicity of Daclatasvir ( CYP3A4 metabolite) due to inhibition of Ritonavir (CYP3A4 inhibitor) decrease the elimination and remain in the plasma.
2. Action is to reduce the Daclatasvir dose from 60mg to 30mg.
Clinical Outcome
Drug Interaction Probability Scale (DIPS)
Editorial Comment
This interaction is highlighted in the Daklinza Prescribing Information ie a PK study is described showing a decrease in exposure of daclatasvir (non dose normalized data) with the recommendation to 'decrease the daclatasvir dose to 30 mg once daily'. This case highlights the importance of the prescriber/health care professional having ready access to the relevant information before starting treatment. This patient should not have been on daclatasvir 60 mg. Note that hepatic impairment (CP-A, CP-B or CP-C) has no effect on daclatasvir exposure unlike the major impact on HCV protease inhibitors. This patient was CP-B.
University of Liverpool Recommendation
Potential interaction - may require close monitoring, alteration of drug dosage or timing of administration