darunavir propylene glycolate: clinical use

Prescribing considerations

• Initiate and supervise treatment through a clinician experienced in HIV management.
• Use with ritonavir and an active background antiretroviral combination.
• Review treatment history and resistance results, particularly after previous protease-inhibitor exposure.
• Check interactions, including inhaled, topical, non-prescription and herbal products.
• Consider swallowing ability and formulation excipients.

Contraindications and cautions

• Hypersensitivity to darunavir or a listed excipient.
• Severe hepatic impairment.
• Co-administration with rifampicin, St John’s wort or lopinavir/ritonavir.
• Co-administration with CYP3A-dependent medicines where increased exposure could cause serious or life-threatening toxicity.
• Use cautiously with mild or moderate hepatic impairment, sulfonamide allergy, haemophilia or chronic viral hepatitis.

Monitoring

• HIV viral load and clinical response; perform resistance testing if response is inadequate or lost.
• Liver tests before and during treatment, with closer surveillance for chronic hepatitis, cirrhosis or abnormal baseline results.
• Interactions whenever treatment is started, stopped or changed.
• Blood glucose, lipids and weight as clinically appropriate.
• Skin reactions, immune-reconstitution symptoms and abnormal bleeding in haemophilia.

Clinical pharmacology

Darunavir inhibits HIV-1 protease dimerisation and catalytic activity, preventing viral polyprotein cleavage and formation of mature infectious virions. CYP3A extensively metabolises it; ritonavir inhibits this pathway and substantially increases exposure. Darunavir is highly protein bound and eliminated mainly through the faecal route.

Formulation and product differences

• The selected product is a film-coated tablet containing darunavir as the propylene glycolate salt.
• It contains lactose, propylene glycol and Sunset Yellow, which may matter with relevant intolerance or hypersensitivity.
• The tablet is relatively large; another tablet presentation or oral suspension may be more appropriate if swallowing is difficult.
• Formulations are not automatically interchangeable without specialist confirmation.

Tablet

Route: Oral

Strengths: 400 mg, 600 mg, 800 mg