Note: This document contains side effect information about cyclobenzaprine. Some dosage forms listed on this page may not apply to the brand name Amrix.

Applies to cyclobenzaprine: oral extended-release capsules, oral immediate-release tablets.

Side effects include:

Drowsiness, dry mouth, dizziness, fatigue, headache.

For Healthcare Professionals

Applies to cyclobenzaprine: compounding powder, oral capsule extended release, oral tablet, oral and topical kit.

General

The most frequently occurring adverse reactions have included dry mouth, dizziness, fatigue, constipation, nausea, dyspepsia, and somnolence.^[Ref]

Nervous system

Elderly patients may be particularly susceptible to the sedation and confusion which may accompany cyclobenzaprine (the active ingredient contained in Amrix) therapy.^[Ref]

Very common (10% or more): Drowsiness (up to 38%)

Common (1% to 10%): Dizziness, somnolence

Postmarketing reports: Headache, serotonin syndrome, seizures, ataxia, tremors, hypertonia, convulsions, abnormal sensations, paresthesia, ageusia^[Ref]

Psychiatric

Common (1% to 10%): Irritability, mental acuity decreased, nervousness

Postmarketing reports: Nervousness, confusion, disorientation, insomnia, depressed mood, anxiety, agitation, psychosis, abnormal thinking and dreaming, hallucinations, excitement^[Ref]

Hypersensitivity

Postmarketing reports: Anaphylaxis, angioedema, pruritus, facial edema, urticaria, rash^[Ref]

Gastrointestinal

Very common (10% or more): Dry mouth (up to 32%)

Common (1% to 10%): Constipation, nausea, dyspepsia, abdominal pain, acid regurgitation, diarrhea

Postmarketing reports: Unpleasant taste, vomiting, anorexia, gastritis, thirst, flatulence, tongue edema^[Ref]

Hepatic

Postmarketing reports: Abnormal liver function, hepatitis, jaundice, cholestasis^[Ref]

Cardiovascular

Postmarketing reports: Syncope, tachycardia, arrhythmia, vasodilation, palpitation, hypotension^[Ref]

Other

Common (1% to 10%): Fatigue

Postmarketing reports: Asthenia, malaise, vertigo^[Ref]

Dermatologic

Postmarketing reports: Sweating^[Ref]

Genitourinary

Postmarketing reports: Urinary frequency and/or retention^[Ref]

Musculoskeletal

Postmarketing reports: Local weakness, dysarthria, muscle twitching^[Ref]

Ocular

Postmarketing reports: Blurred vision, diplopia, tinnitus^[Ref]

Respiratory

Common (1% to 10%): Upper respiratory infection, pharyngitis^[Ref]