Lenacapavir injection is used along with other medications to treat human immunodeficiency virus type 1 (HIV-1) in certain adults. Lenacapavir is in a class of medications called HIV capsid inhibitors. It works by decreasing the amount of HIV in the blood. Although lenacapavir does not cure HIV, it may decrease your chance of developing acquired immunodeficiency syndrome (AIDS) and HIV-related illnesses such as serious infections or cancer. Taking these medications along with practicing safer sex and making other life-style changes may decrease the risk of transmitting (spreading) the HIV virus to other people.

Lenacapavir comes as a solution (liquid) to be given subcutaneously (under the skin) into the abdomen by a doctor or nurse. A first time dose may be given along with lenacapavir oral on day 1 followed by another dose of lenacapavir oral on day 2 and then lenacapavir injection every 6 months thereafter or lenacapavir injection may not be started until 2 weeks after a 3 day regimen of lenacapavir oral is started and then every 6 months thereafter.

Lenacapavir controls HIV but does not cure it. Continue to take lenacapavir even if you feel well. Do not stop lenacapavir without talking to your doctor. If you stop taking lenacapavir, your HIV may become more difficult to treat.

Before receiving lenacapavir injection,

• tell your doctor and pharmacist if you are allergic to lenacapavir, any other medications, or any of the ingredients in lenacapavir injection. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
• Some medications should not be taken with lenacapavir. Make sure you have discussed any medications you are currently taking or plan to take before starting lenacapavir with your doctor and pharmacist. Before starting, stopping or changing any medications while taking lenacapavir, please get the advice of your doctor or pharmacist.
• The following nonprescription or herbal products may interact with lenacapavir: St. John's Wort. Be sure to let your doctor and pharmacist know that you are taking these medications before you start taking lenacapavir. Do not start any of these medications while taking lenacapavir without discussing you're your healthcare provider.
• Lenacapavir may affect any other medications you take for up to 9 months after your last injection so it is important to let your doctor or pharmacist know when you last received lenacapavir before you start any new medications.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking lenacapavir, call your doctor. You should not breastfeed if you are infected with HIV or if you are taking lenacapavir.

It is important to keep all scheduled appointments for lenacapavir injection. If you too much time passes between lenacapavir injections, the medication may not work as well against the virus. If more than 28 weeks have passed since your last lenacapavir injection, your doctor will have to start you on the initial dosing regimen with lenacapavir oral again.

Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medication.

Unless your doctor tells you otherwise, continue your normal diet.

Lenacapavir may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• swelling, pain, redness, itching or lumps at the site of injection
• nausea

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• any new symptoms or signs of infection such as fever, rash, swelling, fatigue, body aches, and joint pain

Lenacapavir may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body's response to lenacapavir.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

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