Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
REGRANEX 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
Recombinant human platelet-derived growth factor (rh PDGF-BB) that promotes chemotaxis and proliferation of fibroblasts, smooth muscle cells, and other cells involved in wound healing, and stimulates granulation tissue formation.
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.
Treatment of lower extremity diabetic neuropathic ulcers that extend into the subcutaneous tissue or beyond and have adequate blood supply.,Off-label: pressure ulcers, venous stasis ulcers, other chronic wounds.
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)
Apply topically once daily, a thin layer to the full area of the ulcer, using a measured amount of gel based on ulcer length and width in centimeters: (length × width × 0.5) grams.
Adults: 5 mg orally three times daily; may increase to 10 mg three times daily based on response. Maximum 30 mg per day.
Terminal half-life ~30-60 minutes after topical application; prolonged in renal impairment (up to 2-3 hours). Clinical context: Short systemic exposure limits off-target effects.
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.
Metabolized locally; no systemic metabolism expected due to topical administration and minimal absorption. If absorbed, degraded by proteolytic enzymes at the wound site.
Hepatic metabolism primarily via CYP3A4, CYP1A2, and CYP2D6; also undergoes N-demethylation and glucuronidation. Active metabolites include norcyclobenzaprine.
Primarily renal; minimal biliary/fecal. Becaplermin is cleared renally (>90% as metabolites) with <2% excreted unchanged. Fecal elimination accounts for <10%.
Renal: ~50% as unchanged drug and metabolites; Fecal: ~40% primarily as metabolites; Biliary: minimal.
~25% bound to plasma proteins (primarily albumin).
~93% bound to albumin and alpha-1-acid glycoprotein.
Vd ~12 L (~0.17 L/kg assuming 70 kg), indicating limited extravascular distribution due to molecular size.
~5 L/kg (range 3–7 L/kg). Clinical meaning: extensive tissue distribution, including central nervous system.
Topical: Negligible systemic bioavailability (<1% of applied dose absorbed; increased with large wounds or impaired skin barrier).
Oral: 33–55% due to first-pass metabolism; lower for immediate-release compared to extended-release (same extent but slower absorption).
No dose adjustment required for renal impairment.
No specific dosing adjustment recommended; use caution in severe renal impairment due to potential accumulation.
No dose adjustment required for hepatic impairment.
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.
Safety and efficacy in pediatric patients have not been established; use not recommended.
Not recommended for children under 15 years; safety and efficacy not established. For adolescents ≥15 years: same as adult dosing.
No specific dose adjustment recommended; use with caution due to potential comorbidities and polypharmacy.
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.
Increased risk of mortality secondary to malignancy in patients treated with 3 or more tubes of REGRANEX (becaplermin) Gel. A postmarketing study showed increased mortality from cancer in patients who used three or more tubes of REGRANEX compared to control patients. REGRANEX should only be used when the benefits can be expected to outweigh the risks. REGRANEX is not recommended in patients with known malignancy.
None
Application to wounds with active malignancy may promote tumor growth. Application to wounds with infection or necrotic tissue should be discontinued until infection is controlled or necrotic tissue debrided. Potential for immunogenicity.
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
Known hypersensitivity to becaplermin or any product component. Application to wounds with known neoplasms or active malignancy. Use on wounds closed by primary intention.
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 known food interactions. Regranex is applied topically and has minimal systemic absorption.
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.
No adequate and well-controlled studies in pregnant women. Animal studies at doses 25-100 times human exposure show no fetal harm. Risk cannot be ruled out; use only if potential benefit justifies potential risk.
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.
It is not known whether becaplermin is excreted in human milk. M/P ratio unknown. Use caution; consider developmental and health benefits of breastfeeding along with mother's clinical need for REGRANEX.
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.
No pharmacokinetic data in pregnancy. Dosage adjustments are not recommended based on current knowledge; use same dosing as non-pregnant adults.
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.
Regranex (becaplermin) is a recombinant platelet-derived growth factor (PDGF) gel indicated for diabetic neuropathic ulcers extending into subcutaneous tissue or deeper. Ensure ulcer is free of infection, necrotic tissue, and has adequate blood supply before initiating therapy. Apply a thin layer once daily, and recalibrate gel amount based on ulcer dimensions (length x width x 0.5 for cm to grams). Do not use on wounds with exposed bone, tendon, or joint. Monitor for increased risk of malignancy; contraindicated in patients with active malignancies. The gel is for single-patient use only; discard tube 30 days after opening.
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.
Wash hands before and after applying Regranex.,Clean the ulcer gently with saline or water before each application.,Apply a thin layer of gel (about 1/16 inch) to the entire ulcer area once daily.,Cover the ulcer with a saline-moistened gauze dressing after applying gel.,Do not use more than the prescribed amount or frequency.,Store Regranex in the refrigerator; do not freeze.,Discard any unused gel in the tube 30 days after first opening.,Report any signs of infection (increased pain, redness, swelling, foul odor) or new skin changes around the wound.,You may need to have your wound measured weekly to adjust the gel amount.,Avoid applying other creams, ointments, or lotions to the same area.
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 REGRANEX vs CYCLOBENZAPRINE HYDROCHLORIDE, answered by our medical review team.
REGRANEX is a Topical Growth Factor (Platelet-Derived) that works by Recombinant human platelet-derived growth factor (rh PDGF-BB) that promotes chemotaxis and proliferation of fibroblasts, smooth muscle cells, and other cells involved in wound healing, and stimulates granulation tissue formation.. 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 REGRANEX and CYCLOBENZAPRINE HYDROCHLORIDE depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of REGRANEX is: Apply topically once daily, a thin layer to the full area of the ulcer, using a measured amount of gel based on ulcer length and width in centimeters: (length × width × 0.5) grams.. 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 REGRANEX 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. REGRANEX is classified as Category C. No adequate and well-controlled studies in pregnant women. Animal studies at doses 25-100 times human exposure show no fetal harm. Risk cannot be ruled out; use only if potential b. 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.