What is cyclobenzaprine?

Cyclobenzaprine is a muscle relaxant. It works by blocking nerve impulses (or pain sensations) that are sent to your brain.

Cyclobenzaprine is used together with rest and physical therapy to treat skeletal muscle conditions such as pain or injury.

Cyclobenzaprine may also be used for other purposes not listed in this medication guide.

Precautions

Do not take cyclobenzaprine if you have used an MAO inhibitor such as isocarboxazid (Marplan), tranylcypromine (Parnate), phenelzine (Nardil), or selegiline (Eldepryl, Emsam) within the past 14 days. Serious, life-threatening side effects can occur if you take cyclobenzaprine before the MAO inhibitor has cleared from your body.

Do not use cyclobenzaprine if you have recently had a heart attack, or if you have:

  • a heart rhythm disorder;
  • congestive heart failure;
  • heart block; or
  • an overactive thyroid.

Before using cyclobenzaprine, tell your doctor if you are allergic to any drugs, or if you have:

  • problems with urination;
  • enlarged prostate;
  • glaucoma; or
  • liver disease.

If you have any of these conditions, you may need a dose adjustment or special tests to safely take cyclobenzaprine.

FDA pregnancy category B. This medication is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

It is not known whether cyclobenzaprine passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

Older adults may be more sensitive to the side effects of this medication.

Cyclobenzaprine can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert.

Avoid drinking alcohol, which can increase some of the side effects of cyclobenzaprine.

Cold or allergy medicine, narcotic pain medicine, sleeping pills, and medicine for seizures, depression or anxiety can add to sleepiness caused by cyclobenzaprine. Tell your doctor if you regularly use any of these medicines, or any other muscle relaxer.

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Instructions

Seek emergency medical attention if you think you have used too much of this medicine. An overdose of cyclobenzaprine can be fatal.

Overdose symptoms may include drowsiness, fast heartbeat, tremors or shaking, slurred speech, confusion, nausea, vomiting, hallucinations (seeing things), chest pain, or seizure (convulsions).

Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at the next regularly scheduled time. Do not take extra medicine to make up the missed dose.

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Side Effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using cyclobenzaprine and call your doctor at once if you have any of these serious side effects:

  • fast, pounding, or uneven heartbeats;
  • chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling;
  • sudden numbness or weakness, especially on one side of the body;
  • sudden headache, confusion, problems with vision, speech, or balance;
  • feeling light-headed, fainting;
  • confusion, weakness, lack of coordination;
  • nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
  • seizure (convulsions);
  • unusual thoughts or behavior, hallucinations (seeing things); or
  • easy bruising or bleeding, unusual weakness.

Less serious side effects may include:

  • dry mouth or throat;
  • blurred vision;
  • drowsiness, dizziness, tired feeling;
  • loss of appetite, stomach pain, nausea;
  • diarrhea, constipation, gas; or
  • muscle weakness.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.

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Interactions

Many drugs can interact with cyclobenzaprine. Below is just a partial list. Tell your doctor if you are using:

  • atropine (Donnatal, and others), benztropine (Cogentin), dimenhydrinate (Dramamine), methscopolamine (Pamine), or scopolamine (Transderm-Scop);
  • a bronchodilator such as ipratroprium (Atrovent) or tiotropium (Spiriva);
  • glycopyrrolate (Robinul);
  • guanethidine (Ismelin);
  • mepenzolate (Cantil);
  • tramadol (Ultram);
  • bladder or urinary medications such as darifenacin (Enablex), flavoxate (Urispas), oxybutynin (Ditropan, Oxytrol), tolterodine (Detrol), or solifenacin (Vesicare); or
  • irritable bowel medications such as dicyclomine (Bentyl), hyoscyamine (Anaspaz, Cystospaz, Levsin, and others), or propantheline (Pro-Banthine).

This list is not complete and there may be other drugs that can interact with cyclobenzaprine. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.

Other Names

Fexmid, Flexeril, cyclobenzaprine, Amrix, and Comfort Pac with Cyclobenzaprine

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Disclaimer

Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2004 Cerner Multum, Inc. Version 2.05. Revision date 8/23/04

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