Somavert (pegvisomant)

Generic name: pegvisomant (peg VIH so mant)
Brand name: Somavert
Drug class: Growth hormone receptor blockers

Somavert (pegvisomant) is a man-made protein that is similar to human growth hormone. Pegvisomant binds to the same receptor in the body as growth hormone, and blocks the effects of growth hormone.

Somavert is used to treat acromegaly (a growth disorder caused by too much growth hormone).

Somavert is usually given after other medications, surgery, or radiation have been tried without successful treatment of symptoms.


You should not use Somavert if you are allergic to pegvisomant.

Before using Somavert, tell your doctor if you have diabetes, liver disease, a latex allergy, or a tumor that secretes growth hormone.

To be sure Somavert is helping your condition and not causing harmful effects, you may need blood tests and CT scans or other radiologic (x-ray) examinations during treatment. Visit your doctor regularly.

Tell your doctor about all other medicines you use, especially insulin or oral diabetes medication, or any narcotic medication.

Stop using Somavert and call your doctor at once if you have a serious side effect such as upper stomach pain, loss of appetite, itching, swelling, rapid weight gain, dark urine, clay-colored stools, or jaundice (yellowing of the skin or eyes).

Before using this medicine

You should not use Somavert if you are allergic to pegvisomant.

To make sure this medicine is safe for you, tell your doctor if you have:

  • diabetes (pegvisomant can lower your blood sugar);
  • liver disease;
  • a latex allergy; or
  • a tumor that secretes growth hormone.

Somavert is not expected to harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether pegvisomant passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Somavert is not approved for use by anyone younger than 18 years old.

How should I take Somavert?

Use Somavert exactly as prescribed by your doctor. Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Somavert is injected under the skin. You may be shown how to use injections at home. Do not self-inject this medicine if you do not understand how to give the injection and properly dispose of used needles and syringes.

Somavert is a powder medicine that must be mixed with a liquid (diluent) before using it. If you are using the injections at home, be sure you understand how to properly mix and store the medicine.

Do not shake the medication bottle or you may ruin the medicine. Prepare your dose only when you are ready to give an injection. Do not use if the medicine has changed colors or has particles in it. Call your pharmacist for new medicine.

Your care provider will show you the best places on your body to inject Somavert. Use a different place each time you give an injection. Do not inject into the same place two times in a row.

Use Somavert regularly to get the most benefit. Get your prescription refilled before you run out of medicine completely.

Each single-use vial (bottle) of this medicine is for one use only. Throw away after one use, even if there is still some medicine left in it after injecting your dose.

Use a disposable needle and syringe only once. Follow any state or local laws about throwing away used needles and syringes. Use a puncture-proof "sharps" disposal container (ask your pharmacist where to get one and how to throw it away). Keep this container out of the reach of children and pets.

You will need frequent blood tests to check your liver function.

Store the powder medicine in a refrigerator. Do not freeze.

After mixing Somavert powder with a diluent, store at room temperature and use within 6 hours after mixing.

Dosing information

Usual Adult Dose for Acromegaly:

Initial dose: 40 mg by subcutaneous injection.
Maintenance dose: 10 to 30 mg by subcutaneous injection daily.

What happens if I miss a dose?

Use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include feeling very tired.

What to avoid

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Somavert side effects

Get emergency medical help if you have signs of an allergic reaction to Somavert: hives; wheezing, difficult breathing; feeling like you might pass out; swelling of your face, lips, tongue, or throat.

Stop using Somavert and call your doctor at once if you have:

  • thickening of the skin or a hard lump where you injected the medicine;
  • easy bruising; or
  • liver problems--nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Common Somavert side effects may include:

  • pain;
  • fever, chills, body aches, flu symptoms;
  • nausea, diarrhea;
  • abnormal liver function tests; or
  • pain or irritation where the medicine was injected.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Somavert?

Tell your doctor about all your current medicines and any you start or stop using, especially:

  • insulin or oral diabetes medication; or
  • narcotic medicine such as fentanyl (Abstral, Actiq, Fentora, Duragesic, Lazanda, Onsolis), hydrocodone (Lortab, Vicodin), hydromorphone (Dilaudid), methadone, morphine, oxycodone (OxyContin, Percocet), and many others.

This list is not complete. Other drugs may interact with pegvisomant, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.