Fostemsavir is an antiretroviral medication used to treat HIV-1 infection, specifically in people with multidrug-resistant HIV who have limited treatment options due to resistance, intolerance, or safety considerations. It was approved by USFDA in the year July 2020. While fostemsavir does not cure HIV, it can help lower your risk of progressing to AIDS and developing HIV-related complications, such as serious infections or certain types of cancer.
BRAND NAME:
Rukobia – It is available in the form of extended- release film coated oral tablets contains 600mg of fostemsavir.
MECHANISM OF ACTION:
Fostemsavir is a prodrug, meaning it becomes active after being metabolized in the body. It is metabolized into temsavir, which directly binds to the gp120 subunit of the HIV-1 envelope glycoprotein. This prevents the virus from attaching to host CD4+ T cells, thus blocking entry into cells.
PHARMACOKINETICS:
Absorption: Fostemsavir is a prodrug that is quickly transformed in the body into its active compound, temsavir. It takes 2 hours to reach its peak plasma concentration.
Distribution: Temsavir shows moderate distribution, binding approximately 88% to plasma proteins, with a volume of distribution of about 29.5 liters.
Metabolism: The metabolism of temsavir occurs primarily through non-CYP hydrolysis of fostemsavir by esterases, with minor contributions from CYP3A4 and UGT1A1. It has an elimination half-life of approximately 11 hours.
Excretion: Temsavir is primarily excreted in the feces, with about 51% eliminated as unchanged drug, and to a lesser extent in the urine, around 33%, mainly in the form of metabolites.
PHARMACODYNAMICS:
Fostemsavir is an HIV-1 attachment inhibitor that works by blocking the virus from binding to and entering CD4+ T cells. Its active form, temsavir, binds to the gp120 protein on the HIV-1 envelope, preventing viral entry. This leads to reduced viral load and increased CD4+ T-cell counts, helping to control HIV infection, especially in patients with multidrug-resistant HIV. Its effects are dose-dependent, and it has a generally favourable safety profile, though it may cause QT prolongation at high doses.
DOSAGE AND ADMINISTRATION:
Fostemsavir are available as extended- release oral tablets with strengths 600mg. It is prescribed to the patient depending on the severity of the medical problem. The dosage can be varying from one patient to other patient.
For treatment of HIV infection in adults, the recommended dose is 600mg twice a day.
DRUG INTERACTIONS:
Some drugs may interact with Fostemsavir and cause serious side effects. So it is required to discuss with the doctor before taking Fostemsavir if the patient is undergoing treatment for any other disease. Below are the few medications should be avoiding while taking Fostemsavir.
- Strong CYP3A4 inducers – Rifampin, Carbamazepin, Phenytoin, St. John’s Wort,
- Phenobarbital.
- Prolong QT interval drugs - Methadone, Amiodarone, sotalol, haloperidol, Macrolides
- CYP3A4 inhibitors – Ritonavir, cobicistat, azole antifungals.
ADVERSE EFFECTS:
- Fainting
- Irregular heartbeat
- Trouble sleeping
- Vomiting
- Belching
- Diarrhea
- Nausea
- Drowsiness
- Unsteadiness
- Muscle pain
- Cramps
- Burning, numbness
OVERDOSE:
Taking overdose of Fostemsavir can cause toxic effects
- Irregular heart beat
- Seizures
