Fexmid Side Effects Center

Last updated on RxList: 8/31/2022
Fexmid Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

What Is Fexmid?

Fexmid (cyclobenzaprine hydrochloride) is a muscle relaxant used as an adjunct to rest and physical therapy for relief of muscle spasm associated with acute, painful musculoskeletal conditions.

What Are Side Effects of Fexmid?

Common side effects of Fexmid include:

Fexmid may cause serious side effects including:

  • hives,
  • difficulty breathing,
  • swelling of your face, lips, tongue, or throat,
  • fast or irregular heartbeats,
  • chest pain or pressure,
  • pain spreading to your jaw or shoulder,
  • sudden numbness or weakness (especially on one side of the body),
  • slurred speech,
  • balance problems,
  • agitation,
  • hallucinations,
  • fever,
  • sweating,
  • shivering,
  • fast heart rate,
  • muscle stiffness,
  • twitching,
  • loss of coordination,
  • nausea,
  • vomiting, and
  • diarrhea
  • Get medical help right away, if you have any of the symptoms listed above.
  • The most common side effects of Fexmid include:
  • drowsiness,
  • tiredness,
  • headache,
  • dizziness,
  • dry mouth,
  • upset stomach,
  • nausea, and
  • constipation

Tell the doctor if you have any side effect that bothers you or that does not go away.

Seek medical care or call 911 at once if you have the following serious side effects:

  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheartedness, or passing out;
  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

Dosage for Fexmid

The recommended dose of Fexmid is 5 mg three times a day.

What Drugs, Substances, or Supplements Interact with Fexmid?

Fexmid may interact with monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs), serotonin–norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants, tramadol, bupropion, meperidine, verapamil, alcohol, barbiturates, other CNS depressants, and guanethidine. Tell your doctor all medications and supplements you use.

Fexmid During Pregnancy or Breastfeeding

Tell your doctor if you are pregnant or plan to become pregnant before using Fexmid; it is unknown how it would affect a fetus. It is unknown if Fexmid passes into breast milk. Because Fexmid is closely related tricyclic antidepressants, some of which are known to pass into breast milk, nursing women should exercise caution. Consult your doctor before breastfeeding. Withdrawal symptoms such as nausea, headache, and malaise may occur if you suddenly stop taking Fexmid.

Additional Information

Our Fexmid (cyclobenzaprine hydrochloride) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

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.

QUESTION

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Fexmid Consumer Information

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.

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Fexmid Professional Information

SIDE EFFECTS

Incidence of most common adverse reactions in the 2 double-blind, placebo-controlled 5 mg studies (incidence of > 3% on cyclobenzaprine HCl 5 mg):

  Cyclobenzaprine HCl Tablets 5 mg Cyclobenzaprine HCl Tablets 10 mg Placebo
N=464 N=249 N=469
Drowsiness 29% 38% 10%
Dry Mouth 21% 32% 7%
Fatigue 6% 6% 3%
Headache 5% 5% 8%
Note: Cyclobenzaprine HCl Tablets 10 mg data are from one clinical trial. Cyclobenzaprine HCl Tablets 5 mg and placebo data are from two studies.

Adverse reactions which were reported in 1% to 3% of the patients were: abdominal pain, acid regurgitation, constipation, diarrhea, dizziness, nausea, irritability, mental acuity decreased, nervousness, upper respiratory infection, and pharyngitis.

The following list of adverse reactions is based on the experience in 473 patients treated with cyclobenzaprine HCl 10 mg in additional controlled clinical studies, 7607 patients in the postmarketing surveillance program, and reports received since the drug was marketed. The overall incidence of adverse reactions among patients in the surveillance program was less than the incidence in the controlled clinical studies.

The adverse reactions reported most frequently with cyclobenzaprine HCl were drowsiness, dry mouth and dizziness. The incidence of these common adverse reactions was lower in the surveillance program than in the controlled clinical studies:

  Clinical Studies with Surveillance Program with
Cyclobenzaprine HCl Tablets 10 mg Cyclobenzaprine HCl Tablets 10 mg
Drowsiness 39% 16%
Dry mouth 27% 7%
Dizziness 11% 3%

Among the less frequent adverse reactions, there was no appreciable difference in incidence in controlled clinical studies or in the surveillance program. Adverse reactions which were reported in 1% to 3% of the patients were: fatigue/tiredness, asthenia, nausea, constipation, dyspepsia, unpleasant taste, blurred vision, headache, nervousness, and confusion.

The following adverse reactions have been reported in postmarketing experience or with an incidence of less than 1% of patients in clinical trials with the 10 mg tablet:

Body as a Whole: Syncope; malaise.

Cardiovascular: Tachycardia; arrhythmia; vasodilatation; palpitation; hypotension.

Digestive: Vomiting; anorexia; diarrhea; gastrointestinal pain; gastritis; thirst; flatulence; edema of the tongue; abnormal liver function and rare reports of hepatitis, jaundice and cholestasis.

Hypersensitivity: Anaphylaxis; angioedema; pruritus; facial edema; urticaria; rash.

Musculoskeletal: Local weakness.

Nervous System and Psychiatric: Seizures, ataxia; vertigo; dysarthria; tremors; hypertonia; convulsions; muscle twitching; disorientation; insomnia; depressed mood; abnormal sensations; anxiety; agitation; psychosis, abnormal thinking and dreaming; hallucinations; excitement; paresthesia; diplopia, serotonin syndrome.

Skin: Sweating.

Special Senses: Ageusia; tinnitus.

Urogenital: Urinary frequency and/or retention.

Causal Relations Hip Unknown

Other reactions, reported rarely for cyclobenzaprine HCl under circumstances where a causal relationship could not be established or reported for other tricyclic drugs, are listed to serve as alerting information to physicians:

Body as a Whole: Chest pain; edema.

Cardiovascular: Hypertension; myocardial infarction; heart block; stroke.

Digestive: Paralytic ileus, tongue discoloration; stomatitis; parotid swelling.

Endocrine: Inappropriate ADH syndrome.

Hematic and Lymphatic: Purpura; bone marrow depression; leukopenia; eosinophilia; thrombocytopenia.

Metabolic, Nutritional and Immune: Elevation and lowering of blood sugar levels; weight gain or loss.

Musculoskeletal: Myalgia.

Nervous System and Psychiatric: Decreased or increased libido; abnormal gait; delusions; aggressive behavior; paranoia; peripheral neuropathy; Bell’s palsy; alteration in EEG patterns; extrapyramidal symptoms.

Respiratory: Dyspnea.

Skin: Photosensitization; alopecia.

Urogenital: Impaired urination; dilatation of urinary tract; impotence; testicular swelling; gynecomastia; breast enlargement; galactorrhea.

To report SUSPECTED ADVERSE REACTIONS, contact Cas per Pharma LLC. at 1-844-5- CASPER (1-844-522-7737) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Read the entire FDA prescribing information for Fexmid (Cyclobenzaprine Hydrochloride Tablets)

© Fexmid Patient Information is supplied by Cerner Multum, Inc. and Fexmid Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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