• blurred vision or eye problems;

• fast heartbeat;

• mood changes, hallucinations (seeing or hearing things), confusion, thoughts of hurting yourself;

• nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);

• ear pain, ringing in your ears;

• feeling light-headed, fainting;

• skin rash or itching; or

• wheezing, difficulty breathing.

Other less serious side effects are more likely to occur, such as:

• feeling anxious, nervous, restless, or irritable;

• increased thirst;

• muscle or joint aches;

• weakness or tiredness;

• sleep problems (insomnia);

• decreased sex drive, impotence, or difficulty having an orgasm; or

• pain, tenderness, itching, or a hard lump where the shot was given.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

What other drugs will affect naltrexone injection?

The pain-relieving effects of any narcotic pain medications you use will be blocked if you use them during your treatment with naltrexone injection. Harmful side effects could also occur.

Before receiving naltrexone injection, tell your doctor if you use any of the following drugs:

• buprenorphine (Buprenex, Subutex);

• butorphanol (Stadol);

• codeine (Tylenol with codeine);

• hydrocodone (Lortab, Vicodin);

• dezocine (Dalgan);

• hydromorphone (Dilaudid);

• levorphanol (Levo-Dromoran);

• meperidine (Demerol);

• methadone (Dolophine, Methadose);

• morphine (Kadian, MS Contin, Roxanol);

• nalbuphine (Nubain);

• nalmefene (Revex);

• naloxone (Narcan);

• oxycodone (OxyContin, Roxicodone, Percocet);

• oxymorphone (Numorphan); or

• propoxyphene (Darvon, Darvocet).

There may be other drugs not listed that can affect naltrexone injection. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

Where can I get more information?

Your doctor has additional information about naltrexone injection written for health professionals that you may read.

What does my medication look like?

Naltrexone injection is available with a prescription under the brand name Vivitrol. Other brand or generic formulations may also be available. Ask your doctor or pharmacist any questions you have about this medication, especially if it is new to you.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.