Brand Names: Amrix, Comfort Pac with Cyclobenzaprine, Fexmid, Flexeril
Generic Name: cyclobenzaprine
- What is cyclobenzaprine?
- What are the possible side effects of cyclobenzaprine?
- What is the most important information I should know about cyclobenzaprine?
- What should I discuss with my healthcare provider before taking cyclobenzaprine?
- How should I take cyclobenzaprine?
- What happens if I miss a dose?
- What happens if I overdose?
- What should I avoid while taking cyclobenzaprine?
- What other drugs will affect cyclobenzaprine?
- Where can I get more information?
What is cyclobenzaprine?
Cyclobenzaprine is a muscle relaxant. It works by blocking nerve impulses (or pain sensations) that are sent to your brain.
Cyclobenzaprine may also be used for purposes not listed in this medication guide.
What are the possible side effects of cyclobenzaprine?
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using cyclobenzaprine and call your doctor at once if you have:
- fast or irregular heartbeats;
- chest pain or pressure, pain spreading to your jaw or shoulder; or
- sudden numbness or weakness (especially on one side of the body), slurred speech, balance problems.
Seek medical attention right away if you have symptoms of serotonin syndrome, such as: agitation, hallucinations, fever, sweating, shivering, fast heart rate, muscle stiffness, twitching, loss of coordination, nausea, vomiting, or diarrhea.
Serious side effects may be more likely in older adults.
Common side effects may include:
- drowsiness, tiredness;
- headache, dizziness;
- dry mouth; or
- upset stomach, nausea, constipation.
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 is the most important information I should know about cyclobenzaprine?
Do not use cyclobenzaprine if you have taken an MAO inhibitor in the past 14 days, such as isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, or tranylcypromine.
What should I discuss with my healthcare provider before taking cyclobenzaprine?
You should not use cyclobenzaprine if you are allergic to it, or if you have:
- a thyroid disorder;
- heart block, heart rhythm disorder, congestive heart failure; or
- if you have recently had a heart attack.
Cyclobenzaprine is not approved for use by anyone younger than 15 years old.
Do not use cyclobenzaprine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.
Some medicines can interact with cyclobenzaprine and cause a serious condition called serotonin syndrome. Be sure your doctor knows if you also take stimulant medicine, opioid medicine, herbal products, or medicine for depression, mental illness, Parkinson's disease, migraine headaches, serious infections, or prevention of nausea and vomiting. Ask your doctor before making any changes in how or when you take your medications.
Tell your doctor if you have ever had:
It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.
It may not be safe to breast-feed while using this medicine. Ask your doctor about any risk.
Older adults may be more sensitive to the effects of this medicine.
How should I take cyclobenzaprine?
Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.
Cyclobenzaprine is usually taken once daily for only 2 or 3 weeks. Follow your doctor's dosing instructions very carefully.
Swallow the capsule whole and do not crush, chew, break, or open it.
Take the medicine at the same time each day.
Call your doctor if your symptoms do not improve after 3 weeks, or if they get worse.
Store at room temperature away from moisture, heat, and light.
What happens if I miss a dose?
Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of cyclobenzaprine can be fatal.
Overdose symptoms may include severe drowsiness, vomiting, fast heartbeats, tremors, agitation, or hallucinations.
What should I avoid while taking cyclobenzaprine?
Avoid driving or hazardous activity until you know how this medicine will affect you. Your reactions could be impaired.
Avoid drinking alcohol. Dangerous side effects could occur.
What other drugs will affect cyclobenzaprine?
Using cyclobenzaprine with other drugs that make you drowsy can worsen this effect. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.
Tell your doctor about all your other medicines, especially:
- bupropion (Zyban, for smoking cessation);
- cold or allergy medicine that contains an antihistamine (Benadryl and others);
- medicine to treat Parkinson's disease;
- medicine to treat excess stomach acid, stomach ulcer, motion sickness, or irritable bowel syndrome;
- medicine to treat overactive bladder; or
- bronchodilator asthma medication.
This list is not complete. Other drugs may affect cyclobenzaprine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.
Where can I get more information?
Your pharmacist can provide more information about cyclobenzaprine.
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