Drowsiness, dizziness, weakness, tiredness, headache, trouble sleeping, nausea, or constipation may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur: mental/mood changes (e.g., confusion, depression, hallucinations), hearing/vision changes, seizures, fast/pounding heartbeat, fainting, black/bloody stools, skin rash or itching, severe mood changes.

Side effects that typically go away as your body adjusts to the medication and do not require medical attention unless they continue for several weeks or are bothersome: drowsiness or unusual tiredness*; increased weakness*; dizziness or lightheadedness; confusion; unusual constipation*; new or unusual bladder symptoms*; trouble sleeping; unusual unsteadiness or clumsiness*.

Seek immediate medical attention if any of these rare but very serious side effects occur: chest pain, shortness of breath.

A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching, swelling, severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

If you are taking more than 30 mg daily, do not stop taking this medication suddenly. Stopping high doses of this medication abruptly can cause convulsions, hallucinations, increases in muscle spasms or cramping, mental changes, or unusual nervousness or restlessness. Consult your physician about how to reduce the dosage gradually before stopping the medication completely.

This drug adds to the effects of alcohol and other CNS depressants (such as antihistamines, sedatives, tranquilizers, prescription pain medications, seizure medications, other muscle relaxants), possibly causing drowsiness. Be sure that your physician knows if you are taking these or other medications. Use caution engaging in activities requiring alertness such as driving or using machinery.

Studies of birth defects with baclofen have not been done with humans. Studies in animals have shown that baclofen, when given in doses several times higher than the amount given to humans, increases the chance of hernias, incomplete or slow development of bones in the fetus, and lower birth weight.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems, seizure disorder, mental/mood disorders, brain disorders (e.g., stroke).

Before having surgery, tell your doctor or dentist that you are using this medication.

Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, the elderly may be more sensitive to the side effects of this drug, especially mental/mood changes.

This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.

This drug passes into breast milk. Consult your doctor before breast-feeding.