A long-acting injectable HIV capsid inhibitor
Lenacapavir
A long-acting HIV medicine, mostly given by injection, used for difficult-to-treat HIV and for HIV prevention.
What is Lenacapavir?
Lenacapavir is a specialist long-acting HIV medicine that works in a new way, by blocking the HIV 'capsid' (the protein shell the virus needs to multiply). It is used for multidrug-resistant HIV, where other medicines no longer work, and is also used for HIV prevention (PrEP). It is usually started with capsules by mouth and then given as an injection under the skin every few months. The most noticeable effects are lumps and reactions where the injection is given. For treatment it is used together with other HIV medicines, not on its own, and it stays in the body for a long time after the last dose.
Education and reference only. This is a plain-language guide to Lenacapavir — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Lenacapavir is an antiretroviral medicine for HIV that belongs to a new group called capsid inhibitors. It is mainly used for people whose HIV has become resistant to many other treatments, where it is combined with other HIV medicines to bring the virus back under control. It is also used to help prevent HIV in people at risk (PrEP). Treatment is usually begun with a short course of tablets and an initial injection, and then continued as an injection under the skin given every few months by a healthcare professional. It is prescribed and supervised by a specialist HIV service.
How it works
HIV needs a protein shell, called the capsid, to copy itself and infect new cells. Lenacapavir locks onto this capsid and stops it working at several stages of the virus's life cycle, which prevents HIV from multiplying. Because the medicine is released slowly from the injection, a single dose keeps working for months, which is why it can be given only a few times a year. For people with resistant HIV it is added to other medicines so the combination together suppresses the virus; for prevention it lowers the chance of HIV taking hold after exposure.
Company & origin
Originated / developed by: Specialist manufacturer.
A specialist long-acting HIV medicine used in the UK for hard-to-treat (multidrug-resistant) HIV and, increasingly, for HIV prevention (PrEP).
Practical use
How to take Lenacapavir
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Follow your HIV team's plan, which usually starts with tablets by mouth and an initial injection, then continues as an injection under the skin every few months.
- Keep taking the rest of your HIV medicines as prescribed, as lenacapavir is used as part of a combination, not on its own.
- Attend your scheduled injection appointments on time, since missing them can let the virus become harder to treat.
- Do not stop treatment without planning it carefully with your HIV team, because the medicine stays in the body for a long time and stopping badly can cause resistance.
- Tell your team about all your other medicines, as some can interact with lenacapavir.
Weighing it up
Advantages & disadvantages of Lenacapavir
Advantages
- Works in a new way, so it can control HIV that has become resistant to many other medicines.
- Long-acting, so the injection is needed only a few times a year rather than daily tablets.
- Also offers a long-acting option for HIV prevention (PrEP) in people at risk.
Disadvantages
- Commonly causes lumps and reactions where the injection is given, which can last a while.
- Stays in the body for many months, so stopping must be carefully planned to avoid resistance.
- For treatment it must be combined with other HIV medicines and used under specialist care.
Practical use
Good to know
A key point with lenacapavir is that, for treating HIV, it is used as part of a combination with other HIV medicines, not by itself, so the rest of the regimen must be kept going. Because it is long-acting, it has a long 'tail': it stays in the body for many months after the last injection. If treatment is stopped, or if the other medicines are not continued, the virus is exposed to low levels of just one drug, which can allow resistance to develop, so stopping must always be planned with the HIV team. The most common effects are at the injection site, where firm lumps (nodules), swelling, redness or pain can last for a while. It is started with tablets and an initial injection, then continued as an injection under the skin every few months at the clinic. Tell your team about all your other medicines, as some interactions are possible.
Who should not take it / use with caution
- People who have had a serious allergic reaction to lenacapavir should not use it.
- It should not be used with certain medicines that strongly lower its levels, such as some used for epilepsy or tuberculosis, so a full medicines list is needed.
- It should only be used under a specialist HIV service that can plan the combination and follow-up.
Monitoring
- Regular blood tests to check the HIV viral load and that the virus stays suppressed.
- Checking injection sites and reviewing any reactions over time.
- Reviewing the whole combination of HIV medicines and any interactions at each visit.
Side effects
- Firm lumps (nodules), swelling, redness or pain where the injection is given, which can last for some time.
- Nausea or headache in some people.
- Rarely, allergic-type reactions, which should be reported to the HIV team.
Key interactions
- Medicines that strongly speed up its breakdown, such as some epilepsy and tuberculosis drugs and the herbal remedy St John's wort, can make it stop working and should be avoided.
- It can affect the levels of some other medicines, so the team checks the whole regimen.
- Always give a full list of prescription, over-the-counter and herbal medicines to your HIV team.
Available as: Tablets to start treatment, plus a solution for injection under the skin given a few times a year.
Answers
Lenacapavir: frequently asked questions
What is lenacapavir used for?
It is a long-acting HIV medicine used for HIV that has become resistant to many other treatments, given with other HIV medicines, and also used for HIV prevention (PrEP).
How often is the injection given?
After starting with tablets and an initial injection, it is usually given as an injection under the skin only a few times a year.
Can I use it on its own to treat HIV?
No. For treating HIV it is used as part of a combination with other HIV medicines; using it alone risks the virus becoming resistant.
Why do lumps appear where I am injected?
Firm lumps (nodules) and reactions at the injection site are the most common side effect because the medicine is released slowly from there; they usually settle over time.
What happens if I stop the medicine?
Lenacapavir stays in the body for many months, so stopping must be planned with your HIV team to avoid the virus developing resistance.
The wider class
About Antiretroviral (HIV capsid inhibitor)
Lenacapavir belongs to the antiretroviral (hiv capsid inhibitor) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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