Fostemsavir

WHY is this medicine prescribed?

Fostemsavir is used along with other medications to treat human immunodeficiency virus (HIV) infection in adults whose HIV could not be successfully treated with other medications, including their current therapy. Fostemsavir is in a class of medications called HIV attachment inhibitors. It works by decreasing the amount of HIV in the blood. Although fostemsavir 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.

HOW should this medicine be used?

Fostemsavir comes as a tablet to take by mouth with or without food. It is usually taken twice a day. Take fostemsavir at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take fostemsavir exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the tablets whole; do not split, chew, or crush them.

Fostemsavir controls HIV but does not cure it. Continue to take fostemsavir even if you feel well. Do not stop taking fostemsavir without talking to your doctor. If you miss doses or stop using fostemsavir, your condition may become more difficult to treat.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

Are there OTHER USES for this medicine?

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

What SPECIAL PRECAUTIONS should I follow?

Before taking fostemsavir,

• tell your doctor and pharmacist if you are allergic to fostemsavir, any other medications, or any of the ingredients in fostemsavir tablets. Ask your pharmacist for a list of the ingredients.
• some medications should not be taken with fostemsavir. Other medications may cause dosing changes or extra monitoring when taken with fostemsavir. Make sure you have discussed any medications you are currently taking or plan to take before starting fostemsavir with your doctor and pharmacist. Before starting, stopping, or changing any medications while taking fostemsavir, please get the advice of your doctor or pharmacist.
• the following herbal products may interact with fostemsavir: St. John's wort. Be sure to let your doctor and pharmacist know that you are taking these medications before you start taking fostemsavir. Do not start any of these medications while taking fostemsavir without discussing with your healthcare provider.
• tell your doctor if you have or have ever had prolonged QT interval (a rare heart problem that may cause fainting or irregular heartbeat), irregular heartbeat, other heart problems. Also tell your doctor if you have or have ever had hepatitis (a viral infection of the liver) or any other liver disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking fostemsavir, call your doctor. You should not breastfeed if you are infected with HIV or are taking fostemsavir.
• you should know that while you are taking medications to treat HIV infection, your immune system may get stronger and begin to fight other infections that were already in your body. This may cause you to develop symptoms of those infections. If you have new or worsening symptoms after starting treatment with fostemsavir, be sure to tell your doctor.

What SPECIAL DIETARY instructions should I follow?

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

What should I do IF I FORGET to take a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

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

• nausea
• vomiting
• diarrhea
• stomach pain
• indigestion
• headache
• tiredness
• rash
• difficulty falling asleep or staying asleep

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

• dizziness, lightheadedness, fainting, or irregular heartbeat

Fostemsavir 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 (https://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. https://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (https://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

What OTHER INFORMATION should I know?

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

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

Fostemsavir tablets may have a slight vinegar-like odor. Ask your pharmacist if you have any questions regarding your medication.

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.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™. © Copyright, 2024. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: August 15, 2020.