Fostemsavir is a novel antiretroviral drug for the treatment of HIV-1 infection, indicated for adult patients with multiply drug-resistant HIV-1 who have experienced treatment failure.

Precautions for Fostemsavir Administration

Indications and Contraindications

Indications: It is only used in adult patients with multiply drug-resistant HIV-1 infection and must be administered in combination with other antiretroviral drugs.

Absolute Contraindications: Patients who are allergic to fostemsavir or any component of its formulation.

Prohibited Concurrent Use: Concurrent use with potent CYP3A inducers (such as rifampicin, carbamazepine, St. John's wort, etc.) is prohibited, as these substances can significantly reduce the blood concentration of temsavir (the active ingredient), leading to treatment failure.

Dosage and Administration Method

Fixed Dosage: 600 mg each time, twice a day. The tablet must be swallowed whole (do not chew or split it).

Effect of Diet: A high-fat meal can increase absorption, but a standard meal has no significant impact. It is recommended to take the medication at regular times.

Administration in Special Populations

Hepatic or Renal Impairment: No dosage adjustment is required for patients with mild to severe hepatic or renal impairment. Patients with end-stage renal disease do not need a supplementary dose after hemodialysis.

Pregnancy and Lactation: Data on use during pregnancy are limited; the benefits and risks must be weighed, and patients should be registered in the Antiretroviral Pregnancy Registry.

Lactation: Use is prohibited during lactation to avoid mother-to-child transmission of HIV and potential risks to the infant.

Drug Interactions

Drugs Requiring Cautious Concurrent Use:

Drugs that prolong the QT interval (e.g., certain antiarrhythmic drugs): May increase the risk of torsades de pointes.

Statins (e.g., rosuvastatin): Should be initiated at the lowest dose, and symptoms of myopathy should be monitored.

Estrogen-containing Contraceptives: The daily estrogen dose must be ≤ 30 μg to prevent the risk of thrombosis.

Monitoring During Fostemsavir Administration

Efficacy Monitoring

Viral Load and CD4 Cell Count: Tested at baseline and regularly after the start of treatment to evaluate the antiviral effect.

Drug Resistance Testing: Genotypic resistance testing should be performed promptly if treatment fails.

Cardiac Monitoring

Electrocardiogram (ECG): Check the QT interval at baseline and regularly during treatment, especially when the drug is used concurrently with other QT-prolonging drugs.

Symptom Observation: Seek medical attention immediately if symptoms such as palpitations or syncope occur.