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Cyclobenzaprine

Enzaris, Flessi, Lospaz, Spazben · ATC code M03BX08

Also known as: Cyclobenzaprin, Siklobenzaprin · Brand names: Enzaris, Flessi, Lospaz, Spazben, Amrix, Fexmid, Tonmya

Key facts
Active substance
Cyclobenzaprine
Drug class
Muscle relaxant
ATC code
M03BX08
Authorisation
authorised nationally; no central EU authorisation
Information as of
2026-10-27

Key facts

Cyclobenzaprine is a centrally acting skeletal muscle relaxant structurally related to tricyclic antidepressants. Per the US label it is used short-term to relieve muscle spasm from acute, painful musculoskeletal conditions.

What it is used for

  • Adjunct to rest and physical therapy for muscle spasm associated with acute, painful musculoskeletal conditions
  • Not effective for spasticity from cerebral or spinal cord disease or in children with cerebral palsy

Dosing

  • Usually 5 mg three times a day; may be increased to 10 mg three times a day based on response
  • Short-term only: use for longer than 2 or 3 weeks is not recommended
  • Hepatic impairment and elderly: consider less frequent dosing; mild hepatic impairment start at 5 mg and titrate slowly
  • Moderate to severe hepatic impairment: not recommended

Contraindications

  • Hypersensitivity to any component
  • MAO inhibitors concomitantly or within 14 days after discontinuation
  • Acute recovery phase of myocardial infarction, arrhythmias, heart block, conduction disturbances or congestive heart failure
  • Hyperthyroidism

Important warnings

  • Potentially life-threatening serotonin syndrome with SSRIs, SNRIs, TCAs, tramadol, bupropion, meperidine, verapamil or MAO inhibitors
  • Structurally related to tricyclic antidepressants, which have been reported to produce arrhythmias, sinus tachycardia and prolonged conduction time
  • Anticholinergic action: caution with urinary retention, angle-closure glaucoma or increased intraocular pressure
  • Sedation; may impair mental or physical abilities and enhance effects of alcohol and other CNS depressants

Side effects

  • Most common: drowsiness (29% with 5 mg, 38% with 10 mg) and dry mouth (21% and 32%)
  • Others: fatigue, headache, dizziness, nausea, constipation

Interactions

  • MAO inhibitors: contraindicated
  • Serotonergic drugs: risk of serotonin syndrome
  • Alcohol, barbiturates and other CNS depressants: effects may be enhanced

Pregnancy and breastfeeding

  • Pregnancy: use only if clearly needed; no adequate studies in pregnant women
  • Nursing: unknown whether excreted in human milk; use with caution

Summary of the official product information, written with AI (Claude, Anthropic) on 2026-10-28. Every number was checked automatically against the original text. Not reviewed by a physician – the full official text is authoritative.

Full official text →

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For patients

Patient information (US)

This product has no separate US patient information.

Authorisation and brand names by country

Medicines with exactly this active-substance composition, as listed in the national registers – alphabetical and without ranking. Whether a product is currently available is not shown here.

Turkey

  • EnzarisALİ RAİF İLAÇ SAN. A.Ş. · 3 register entries
  • FlessiMENARİNİ İLAÇ SANAYİ VE TİC. A.Ş. · 2 register entries
  • LospazDEVA HOLDİNG A.Ş. · 1 register entry
  • SpazbenGENVEON İLAÇ SAN. VE TİC. A.Ş. · 2 register entries

Source: TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, as of 2026-10-16

USA

  • AmrixCephalon, LLC · 1 register entry
  • FexmidRising Pharma Holdings, Inc. · 1 register entry
  • TonmyaTonix Medicines, Inc. · 1 register entry

Source: U.S. FDA – Drug labels (openFDA/DailyMed), as of 2026-10-28

Brand names in 3 more European countries
Italy
Flexiban
Portugal
Flexiban, Miodia
Spain
Yurelax

EMA – Article 57 product data (EU/EEA), 2026-10-28

Medelix receives no money from pharmaceutical companies. Brand names are listed alphabetically and without ranking.

Other substances in the same group

Another question about this substance?

Medelix answers clinical questions from guidelines, studies and product information – every claim with its source.

Sources

  1. U.S. Food and Drug Administration. CYCLOBENZAPRINE HYDROCHLORIDE (TruPharma LLC) – Prescribing Information, 2026-07-17. DailyMed (NLM), 2026-10-27. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=08adc97f-feef-46fb-ac75-f015b4f3a43a
  2. TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, 2026-10-16. https://www.titck.gov.tr/dinamikmodul/85
  3. U.S. FDA – Drug labels (openFDA/DailyMed), 2026-10-28. https://dailymed.nlm.nih.gov/dailymed/
  4. Wikidata (CC0): ATC M03BX.

Editorial: Medelix editorial team · last updated 2026-10-27 · How these pages are made · Report an error

Source: U.S. Food and Drug Administration (FDA), prescribing information, via DailyMed (NLM); public domain. Not advertising, not a treatment recommendation. For questions about your own treatment, ask your doctor or pharmacist.