Cyclobenzaprine Hydrochloride
Pronunciation: pronunciation varies by local usage.
- Generic name
- cyclobenzaprine hydrochloride
- Drug class
- centrally acting skeletal-muscle relaxant
- Route
- oral
Prescription_only
Trade names by country: United States
United States: AMRIX, Fexmid, TONMYA · Full directory
What cyclobenzaprine hydrochloride is and how it works
Cyclobenzaprine is used for a short period alongside rest and physical therapy for muscle spasm associated with acute painful musculoskeletal conditions. Evidence for longer use is inadequate, and it is not effective for spasticity caused by brain or spinal-cord disease. cyclobenzaprine hydrochloride is prescribed for the treatment of approved medical conditions. This medication should be taken exactly as directed by your healthcare provider. Do not adjust your dosage without medical supervision. Contact your healthcare provider immediately if you experience any unusual or severe side effects. cyclobenzaprine hydrochloride works through its pharmacological mechanism to achieve its therapeutic effects. Regular monitoring and follow-up appointments are important to ensure the safe and effective use of this medication. Store this medication at room temperature away from moisture and heat. Keep all medications out of reach of children and pets. (1)
Uses, formulations, monitoring, and supply rules can differ by patient, product, and country. Follow the exact local product information and professional advice.
Mechanism of action: how cyclobenzaprine hydrochloride works
Cyclobenzaprine is a centrally acting skeletal-muscle relaxant, structurally related to the tricyclic antidepressants, with pronounced anticholinergic and sedating effects. (1)
What cyclobenzaprine hydrochloride is used for
Short-term adjunct to rest and physical therapy for acute painful musculoskeletal spasm under the US label
The US label indicates cyclobenzaprine for the relief of muscle spasm associated with acute, painful musculoskeletal conditions, used for short periods (up to two or three weeks) together with rest and physical therapy. (1)
Not established for chronic use or CNS spasticity
The label states cyclobenzaprine has not been shown effective for spasticity associated with cerebral or spinal cord disease, and evidence supporting effectiveness beyond two to three weeks of treatment is not available. (1)
Before taking cyclobenzaprine hydrochloride
Do not take / not appropriate for
- Do not take cyclobenzaprine if you have had a hypersensitivity (allergic) reaction to cyclobenzaprine or to any component of the product. (all countries)
- Do not take cyclobenzaprine while you are taking a monoamine oxidase (MAO) inhibitor, or within 14 days after stopping one. Hyperpyretic crisis, seizures, and deaths have occurred when cyclobenzaprine or structurally similar tricyclic medicines were given together with MAO inhibitors. (all countries)
- Do not take cyclobenzaprine during the acute recovery phase after a heart attack (myocardial infarction). (all countries)
- Do not take cyclobenzaprine if you have an irregular heartbeat (arrhythmia), heart block, or another disturbance of the electrical conduction of the heart. (all countries)
- Do not take cyclobenzaprine if you have congestive heart failure. (all countries)
- Do not take cyclobenzaprine if you have an overactive thyroid gland (hyperthyroidism). (all countries)
Tell your clinician about
- Every other medicine you take, especially serotonergic medicines such as SSRIs and SNRIs — a potentially life-threatening serotonin syndrome has been reported when cyclobenzaprine is used in combination with them.
- Any MAO inhibitor you are taking now or have stopped taking within the past two weeks.
- A recent heart attack, an irregular heartbeat, heart block or other problems with the electrical signals in your heart, or heart failure — your doctor may tell you not to take cyclobenzaprine.
- An overactive thyroid gland, now or at any time in the past.
- How much alcohol you drink, and any barbiturates, sedatives or other CNS depressants you take — cyclobenzaprine may enhance the effects of alcohol, barbiturates and other CNS depressants.
- Your age: older adults should not usually take cyclobenzaprine, because it is not as safe or effective as other medicines used for the same condition.
- That this medicine may make you drowsy — do not drive or operate machinery until you know how cyclobenzaprine affects you.
How to take cyclobenzaprine hydrochloride
- Take only as prescribed and generally for no longer than two or three weeks. Use alongside the recommended physical treatment plan.
- Dose selection changes with patient response, age, and liver function. No public calculator is enabled.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1)
Missed dose
Follow the pharmacy label. Do not double; ask the pharmacist if timing is unclear.
Overdose
Cyclobenzaprine overdose can be life-threatening and requires immediate Poison Control/emergency assessment even if symptoms seem mild. (1)
Side effects
Do not drive until effects are known; report fainting, palpitations, severe confusion, urinary retention, or eye pain.
Drowsiness
Incidence: Most common adverse reaction reported on the US label
Dry mouth
Incidence: Common anticholinergic effect
Dizziness
Incidence: Common
Fatigue
Incidence: Common
Serious warnings
Contraindicated with MAO inhibitors and in certain recent heart attack, arrhythmia, conduction-block, heart-failure, and hyperthyroid settings — serious
Symptoms: Contraindicated with MAO inhibitors and in certain recent heart attack, arrhythmia, conduction-block, heart-failure, and hyperthyroid settings.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (1)
Serotonin syndrome can occur with serotonergic medicines — serious
Symptoms: Serotonin syndrome can occur with serotonergic medicines: agitation, confusion, sweating, fever, fast heartbeat, tremor, stiffness, diarrhoea, or loss of coordination require urgent help.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (1)
Sedation can impair driving — serious
Symptoms: Sedation can impair driving; alcohol and other CNS depressants increase impairment.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (1)
Anticholinergic effects can worsen glaucoma or urinary retention — serious
Symptoms: Anticholinergic effects can worsen glaucoma or urinary retention.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (1)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| MAO inhibitors | Contraindicated — do not use with an MAOI or within the label's washout period; combined use has been associated with hyperpyrexia, seizures, and death. | (1) |
| Serotonergic antidepressants and analgesics, alcohol, sedatives, and anticholinergic medicines | Increased risk of serotonin syndrome, additive sedation, and additive anticholinergic effects; pharmacist review is required before combining. | (1) |
Pregnancy, breastfeeding, kidney/liver function, age
Pregnancy
Use only after clinician assessment. (1)
Breastfeeding
Discuss infant sedation and limited evidence. (1)
Children
Use only where the exact label supports the patient's age. (1)
Older_adults
Exposure and adverse effects are increased; consider alternatives. (1)
Hepatic_impairment
May increase exposure; formulation and severity-specific restrictions apply. (1)
Monitoring
During treatment
- Benefit and need within the short treatment window
- Sedation, falls, anticholinergic effects, and serotonin toxicity
- Cardiac symptoms and liver-risk context
Storage
Store in the dispensed container at the labeled temperature and out of reach of children.
Professional information
Clinician-facing context only. This section does not replace the current local product information, hepatic function assessment, or specialist advice for complex comorbidity.
United States (oral, immediate-release)
Indication: Short-term (2-3 week) adjunct to rest and physical therapy for acute, painful musculoskeletal conditions
Dose summary: US labelling states 5 mg three times a day, which may be increased to 10 mg three times a day based on individual response; use beyond two to three weeks is not recommended.
Renal context: No renal-specific dose adjustment is specified in the US label. Cyclobenzaprine is largely metabolised hepatically; the label instead gives hepatic-impairment guidance -- see the hepatic note below. (1)
Hepatic guidance
The US label directs starting at 5 mg with slow upward titration in mild hepatic impairment, and states use in moderate-to-severe hepatic impairment is not recommended because of a lack of data.
Overdose note
Suspected overdose requires urgent assessment; cyclobenzaprine shares serotonergic and anticholinergic toxicity risk with tricyclic antidepressants. Obtain the exact product, dose, timing, co-exposures, and follow local toxicology/emergency protocols. (1)
Frequently asked questions
What is cyclobenzaprine hydrochloride used for?
cyclobenzaprine hydrochloride is prescribed for approved indications. Always follow your healthcare provider's guidance.
What are the side effects of cyclobenzaprine hydrochloride?
Common side effects may include gastrointestinal symptoms and headache. Serious side effects require immediate medical attention.
Can I take cyclobenzaprine hydrochloride with other medications?
Always inform your healthcare provider about all medications you are taking, including over-the-counter products and supplements.
What is the mechanism of action of cyclobenzaprine hydrochloride?
Cyclobenzaprine is a centrally acting skeletal-muscle relaxant, structurally related to the tricyclic antidepressants, with pronounced anticholinergic and sedating effects. (1)
What is the generic name of Cyclobenzaprine Hydrochloride?
The generic name is cyclobenzaprine hydrochloride.
What class of drug is cyclobenzaprine hydrochloride?
Cyclobenzaprine Hydrochloride is classed as: centrally acting skeletal-muscle relaxant.
References
- Cyclobenzaprine hydrochloride tablets — prescribing informationU.S. National Library of Medicine (DailyMed) · United States · dated unknown · accessed 2026-07-22 · source 1
- CYCLOBENZAPRINE HYDROCHLORIDE TABLET, FILM COATED [REMEDYREPACK INC.] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 2
- Cyclobenzaprine — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 3
- CYCLOBENZAPRINE HYDROCHLORIDE — FDA approval record (Drugs@FDA ANDA208170)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 4
- cyclobenzaprine — RxNorm normalized drug concept (RXCUI 21949)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 5
Brand names by country
Single-ingredient cyclobenzaprine hydrochloride names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
United States
- AMRIX15 mg, 30 mg · cephalon, llc
- Fexmid7.5 mg · rising pharma holdings, inc.
- TONMYA2.8 mg · tonix medicines, inc.