Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
TRANCOPAL vs CYCLOBENZAPRINE HYDROCHLORIDE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Trancopal (chlormezanone) is a centrally acting muscle relaxant and anxiolytic. Its exact mechanism is not fully understood, but it is believed to act on the central nervous system by depressing polysynaptic reflexes and possibly through GABAergic modulation.
Cyclobenzaprine is a centrally acting muscle relaxant that reduces tonic somatic motor activity at the supraspinal level, primarily at the brainstem reticular formation and descending pathways. It is structurally related to tricyclic antidepressants and inhibits reuptake of norepinephrine and serotonin, but the direct relationship to its muscle relaxant effects is not fully established.
Adjunctive therapy for acute muscle spasm associated with painful musculoskeletal conditions,Anxiety and tension states
Treatment of muscle spasm associated with acute, painful musculoskeletal conditions (FDA approved),Adjunct to rest and physical therapy for relief of muscle spasm (FDA approved)
200-400 mg orally every 6 hours as needed for acute musculoskeletal pain; maximum 1.6 g per day.
Adults: 5 mg orally three times daily; may increase to 10 mg three times daily based on response. Maximum 30 mg per day.
Terminal elimination half-life: 20-30 hours in healthy adults. Prolonged in hepatic impairment (up to 60 hours).
Terminal half-life: 18–24 hours (range 8–37 hours). Clinical context: requires multiple doses to achieve steady state (5–6 days); active metabolite norcyclobenzaprine has half-life ~30 hours.
Hepatic metabolism; primarily via oxidation and conjugation; exact enzymes not well characterized.
Hepatic metabolism primarily via CYP3A4, CYP1A2, and CYP2D6; also undergoes N-demethylation and glucuronidation. Active metabolites include norcyclobenzaprine.
Primarily renal: ~95% as metabolites (glucuronides, sulfate conjugates) with <1% unchanged. Fecal: <5%.
Renal: ~50% as unchanged drug and metabolites; Fecal: ~40% primarily as metabolites; Biliary: minimal.
~99% bound primarily to albumin; minimal binding to α1-acid glycoprotein.
~93% bound to albumin and alpha-1-acid glycoprotein.
0.2-0.3 L/kg, indicating limited distribution primarily to extracellular fluid and well-perfused tissues.
~5 L/kg (range 3–7 L/kg). Clinical meaning: extensive tissue distribution, including central nervous system.
Oral bioavailability ~25% due to extensive first-pass hepatic metabolism (high extraction ratio).
Oral: 33–55% due to first-pass metabolism; lower for immediate-release compared to extended-release (same extent but slower absorption).
GFR <30 m L/min: avoid use. GFR 30-50 m L/min: reduce dose by 50% or extend interval. Not studied in severe impairment.
No specific dosing adjustment recommended; use caution in severe renal impairment due to potential accumulation.
Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: contraindicated.
Child-Pugh Class A or B: No adjustment. Child-Pugh Class C: Contraindicated due to risk of toxicity (minimal data). Use with caution in mild to moderate impairment; consider lower starting dose.
Not recommended for use in children under 16 years due to lack of safety and efficacy data.
Not recommended for children under 15 years; safety and efficacy not established. For adolescents ≥15 years: same as adult dosing.
Start at lower end of dosing range; 200 mg orally every 8-12 hours. Caution due to increased risk of sedation and falls.
Start with 5 mg once daily; increase slowly to a maximum of 10 mg three times daily over 2 weeks. Increased sensitivity; monitor for anticholinergic effects and sedation.
None
None
May cause drowsiness, dizziness, or blurred vision; caution in patients requiring mental alertness,Avoid concurrent use with alcohol or other CNS depressants,Use with caution in patients with hepatic or renal impairment,May be habit-forming; potential for dependence with prolonged use
Serotonin syndrome risk, especially with concomitant serotonergic drugs (e.g., SSRIs, SNRIs, MAOIs),Sedation and impairment of motor skills; caution with driving or operating machinery,Anticholinergic effects (e.g., urinary retention, angle-closure glaucoma, constipation),Cardiovascular effects: tachycardia, QT prolongation, arrhythmias (especially in elderly or with pre-existing heart disease),Hepatic impairment: use with caution; reduced clearance in mild impairment, avoid in severe impairment,Withdrawal symptoms after abrupt discontinuation: dysphoria, anxiety, insomnia,Elderly patients: increased risk of falls, confusion, anticholinergic toxicity
Hypersensitivity to chlormezanone or any component of the formulation,Acute intermittent porphyria,Concomitant use with MAO inhibitors
Hypersensitivity to cyclobenzaprine or any component of the formulation,Concomitant use or within 14 days of MAO inhibitors (hypertensive crisis risk),Acute recovery phase after myocardial infarction,Arrhythmias, heart block, or conduction disturbances,Hyperthyroidism,Severe hepatic impairment
No specific food interactions reported. However, avoid alcohol as it potentiates CNS depression.
Alcohol should be avoided due to additive CNS depression. Grapefruit juice may increase cyclobenzaprine levels (though data is limited, caution is advised). High-fat meals may delay absorption but not clinically significant. No specific dietary restrictions are required.
Trancopal (chlormezanone) is a centrally acting muscle relaxant. Studies in animals have shown teratogenic effects. During the first trimester, there is a risk of congenital malformations, particularly neural tube defects, based on limited human data. In the second and third trimesters, potential risks include fetal growth restriction and altered fetal muscle tone. The drug should be avoided throughout pregnancy unless benefits clearly outweigh risks.
Cyclobenzaprine is classified as FDA Pregnancy Category B. Animal reproduction studies have not shown fetal risk, and there are no adequate and well-controlled studies in pregnant women. Risk cannot be ruled out. First trimester: Limited human data, but no structural anomalies reported. Second trimester: No specific adverse effects documented. Third trimester: Potential for neonatal withdrawal symptoms (e.g., jitteriness, respiratory depression) if used near term.
Chlormezanone is excreted into breast milk. The milk-to-plasma (M/P) ratio is unknown. Infant exposure is expected to be low due to limited data, but potential for adverse effects such as sedation or hypotonia exists. Consider alternative medications. The American Academy of Pediatrics classifies the drug as compatible with breastfeeding, but caution is advised. Monitor infant for drowsiness or feeding difficulties.
Cyclobenzaprine is excreted into breast milk in low amounts; the M/P ratio is unknown. Due to its anticholinergic effects, there is potential for adverse effects in the nursing infant (e.g., sedation, constipation). The American Academy of Pediatrics considers it compatible with breastfeeding, but caution is advised; alternatives may be preferred.
Pharmacokinetic changes in pregnancy, such as increased volume of distribution and enhanced clearance, may reduce serum concentrations of chlormezanone. No specific dose adjustments have been established. Clinical response should guide dosing, and the lowest effective dose should be used. Gradual tapering recommended to avoid withdrawal symptoms.
No specific dose adjustments are recommended during pregnancy. Pharmacokinetic parameters (e.g., clearance) are not significantly altered by pregnancy. Use the lowest effective dose for the shortest duration due to lack of safety data.
Trancopal (chlormezanone) is a centrally acting muscle relaxant and anxiolytic. Due to risk of severe cutaneous adverse reactions (e.g., Stevens-Johnson syndrome), it has been withdrawn in many countries. Not recommended for first-line use. Monitor for sedation and avoid combining with other CNS depressants.
Cyclobenzaprine is structurally related to tricyclic antidepressants and shares similar anticholinergic and sedative properties. Onset of action for muscle relaxation is typically 1 hour, but maximal effect may take several days. Avoid use in patients with hyperthyroidism, cardiac disease, or those on MAOIs. Not recommended for use longer than 2-3 weeks due to lack of evidence for chronic use. Caution in elderly due to anticholinergic effects and fall risk.
Avoid alcohol and other CNS depressants as they increase drowsiness and dizziness.,Do not drive or operate heavy machinery until you know how this medication affects you.,Seek immediate medical attention if you develop rash, blisters, or signs of an allergic reaction.,Take exactly as prescribed; do not increase dose or frequency without consulting your doctor.,Do not stop abruptly; gradual taper may be needed to avoid withdrawal symptoms.
This medication may cause drowsiness, dizziness, or blurred vision; avoid driving or operating machinery until you know how it affects you.,Do not drink alcohol or use other CNS depressants (e.g., benzodiazepines, opioids) while taking this medication, as it may increase sedation.,Take this medication exactly as prescribed, usually 3 times a day. Do not take more or less than directed.,This medication is intended for short-term use (up to 2-3 weeks) for muscle spasm. Do not use it for longer without consulting your doctor.,If you experience dry mouth, try sucking on sugar-free candy or ice chips. If you have difficulty urinating or vision changes, contact your doctor.,Do not stop taking this medication abruptly without consulting your doctor, although withdrawal is uncommon with short-term use.
No interactions on record
"The combination of cyclobenzaprine and carbinoxamine results in additive central nervous system depression due to their shared anticholinergic and sedative properties. This can lead to excessive sedation, impaired cognitive and motor function, and increased risk of falls or accidents. Severe cases may result in respiratory depression, especially in elderly patients or those with preexisting conditions."
"Cyclobenzaprine, a centrally acting muscle relaxant with tricyclic antidepressant (TCA)-like structure, and Dezocine, an opioid partial agonist analgesic with mu-opioid receptor activity, both depress the central nervous system (CNS) and have additive serotonergic effects. Concomitant use increases the risk of excessive CNS depression, manifesting as sedation, respiratory depression, and impaired psychomotor function, as well as potential serotonin syndrome due to combined serotonergic activity. Clinically, patients may experience profound drowsiness, confusion, respiratory compromise, and in severe cases, coma or death from respiratory failure."
"Lumacaftor, a potent inducer of cytochrome P450 (CYP) 3A4, significantly reduces the systemic exposure of cyclobenzaprine, a CYP3A4 substrate. This results in decreased plasma concentrations of cyclobenzaprine, potentially leading to reduced therapeutic efficacy for muscle spasm relief. Patients may require dose adjustments or alternative therapies to maintain clinical benefit."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about TRANCOPAL vs CYCLOBENZAPRINE HYDROCHLORIDE, answered by our medical review team.
TRANCOPAL is a Skeletal Muscle Relaxant that works by Trancopal (chlormezanone) is a centrally acting muscle relaxant and anxiolytic. Its exact mechanism is not fully understood, but it is believed to act on the central nervous system by depressing polysynaptic reflexes and possibly through GABAergic modulation.. CYCLOBENZAPRINE HYDROCHLORIDE is a Skeletal Muscle Relaxant that works by Cyclobenzaprine is a centrally acting muscle relaxant that reduces tonic somatic motor activity at the supraspinal level, primarily at the brainstem reticular formation and descending pathways. It is structurally related to tricyclic antidepressants and inhibits reuptake of norepinephrine and serotonin, but the direct relationship to its muscle relaxant effects is not fully established.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between TRANCOPAL and CYCLOBENZAPRINE HYDROCHLORIDE depend on the specific clinical indication. These are both Skeletal Muscle Relaxant agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of TRANCOPAL is: 200-400 mg orally every 6 hours as needed for acute musculoskeletal pain; maximum 1.6 g per day.. The standard adult dose of CYCLOBENZAPRINE HYDROCHLORIDE is: Adults: 5 mg orally three times daily; may increase to 10 mg three times daily based on response. Maximum 30 mg per day.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between TRANCOPAL and CYCLOBENZAPRINE HYDROCHLORIDE in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. TRANCOPAL is classified as Category C. Trancopal (chlormezanone) is a centrally acting muscle relaxant. Studies in animals have shown teratogenic effects. During the first trimester, there is a risk of congenital malfor. CYCLOBENZAPRINE HYDROCHLORIDE is classified as Category A/B. Cyclobenzaprine is classified as FDA Pregnancy Category B. Animal reproduction studies have not shown fetal risk, and there are no adequate and well-controlled studies in pregnant . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.