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Published on: January 7, 2019
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A potential drug interaction between phenobarbital and dolutegravir: A case report
Shinichi Hikasa1, Akihiro Sawada2, Hitomi Seino3
1Department of Pharmacy, The Hospital of Hyogo College of Medicine, 1-1, Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan.
Summary
Phenobarbital (PB) significantly reduces dolutegravir (DTG) plasma concentrations in HIV patients. This dose-dependent effect highlights potential drug interaction concerns for antiretroviral therapy.
Area of Science:
- Pharmacology
- Infectious Diseases
- Clinical Pharmacy
Background:
- Dolutegravir (DTG) is a key integrase inhibitor for Human Immunodeficiency Virus (HIV) treatment.
- Drug interactions can alter antiretroviral therapy efficacy and safety.
- Phenobarbital (PB) is an antiepileptic drug with known enzyme-inducing properties.
Observation:
- A case study of an HIV-infected patient revealed fluctuating DTG plasma concentrations.
- Concomitant administration of varying phenobarbital (PB) doses correlated with DTG levels.
- DTG levels were observed to be 0.934, 0.584, 1.003, and 3.25 μg/mL with PB doses of 40, 70, 30, and 0 mg, respectively.
Findings:
- Phenobarbital (PB) significantly reduces dolutegravir (DTG) plasma concentrations.
- The reduction in DTG plasma concentration by PB is dose-dependent.
- This interaction can lead to sub-therapeutic levels of DTG.
Implications:
- Clinicians should monitor DTG levels when co-prescribing with PB.
- Alternative anticonvulsant therapy may be considered in HIV patients on DTG.
- Understanding drug-drug interactions is crucial for optimizing HIV treatment regimens.
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