fostemsavir tromethamine at a glance
Medicine class
HIV-1 attachment inhibitor and antiretroviral prodrug
Licensed role
Specialist treatment of multidrug-resistant HIV-1 in adults, alongside other antiretrovirals
Administration
Swallow the prolonged-release tablet whole with water; do not chew, crush or split it
Food
May be taken with or without food
What is fostemsavir tromethamine used for?
Its licensed use is limited to specialist HIV care.
Used with other antiretrovirals for adults with multidrug-resistant HIV-1 when a suppressive antiviral combination cannot otherwise be constructed.
How does fostemsavir tromethamine work?
Fostemsavir is converted to temsavir, which binds to gp120 on the HIV-1 envelope. This blocks interaction with the CD4 receptor and helps prevent the virus entering human cells.
fostemsavir tromethamine preparations and strengths
Modified-release tablet
Route: Oral
Strengths: 600 mg
How to take fostemsavir tromethamine
Follow the specialist HIV team's instructions.
Swallow the tablet whole with water.
Do not chew, crush or split it because this can alter prolonged release.
It may be taken with or without food.
Do not stop treatment without discussing it with the HIV team.
fostemsavir tromethamine side effects
Common or expected effects
- Diarrhoea, nausea, vomiting or abdominal pain
- Headache
- Rash or itching
- Dizziness, drowsiness or altered taste
- Indigestion or wind
- Difficulty sleeping
- Fatigue or muscle pain
- Changes in liver enzymes, creatinine or creatine phosphokinase
Get urgent medical advice
- New or worsening infection or inflammation from immune reconstitution inflammatory syndrome
- QT-interval prolongation, particularly with fainting or significant palpitations
- Autoimmune inflammation causing marked weakness, joint swelling, tremor or other significant new symptoms
fostemsavir tromethamine in pregnancy
Pregnancy information is limited, and precautionary avoidance is preferred. Anyone pregnant or planning pregnancy should promptly contact their specialist HIV and maternity teams without interrupting HIV treatment.
fostemsavir tromethamine while breastfeeding
It is unknown whether fostemsavir or temsavir enters human milk. The product information recommends against breastfeeding. Formula feeding is described as the safest option, while anyone with sustained viral suppression who wishes to breastfeed needs early specialist planning and close monitoring.
fostemsavir tromethamine interactions
A full review of medicines and herbal products is essential because interactions may reduce HIV control or increase adverse effects.
Strong CYP3A inducers, including rifampicin, carbamazepine, phenytoin, mitotane, enzalutamide and St John’s wort
Contraindicated because they can substantially reduce temsavir exposure and cause loss of virological response.
Elbasvir with grazoprevir
Not recommended because grazoprevir exposure may rise, increasing the risk of raised liver enzymes.
Atorvastatin, rosuvastatin, simvastatin, pitavastatin and fluvastatin
Exposure may increase, requiring careful selection, titration and adverse-effect monitoring.
Common questions about fostemsavir tromethamine
Answers are fully visible for fast scanning and source review.
What is fostemsavir tromethamine used for?
It is used with other antiretrovirals for adults with multidrug-resistant HIV-1 when a suppressive combination cannot otherwise be constructed.
Does it cure HIV?
No. It helps control HIV-1 but does not eliminate the infection.
Can the tablets be crushed or split?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.