Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
KEPIVANCE vs AMRIX
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Kepivance (palifermin) is a recombinant human keratinocyte growth factor (KGF) that binds to the KGF receptor, a splice variant of fibroblast growth factor receptor 2 (FGFR2b), stimulating proliferation, differentiation, and migration of epithelial cells, including those in the gastrointestinal tract.
Centrally acting muscle relaxant; it is the R-enantiomer of baclofen. Agonist at GABA-B receptors in the spinal cord, leading to inhibition of monosynaptic and polysynaptic spinal reflexes, thereby reducing muscle spasticity.
FDA-approved: To decrease the incidence and duration of severe oral mucositis in patients with hematologic malignancies receiving myelotoxic therapy requiring hematopoietic stem cell support.,Off-label: Prevention of oral mucositis in other cancers; management of acute radiation-induced mucositis.
Treatment of spasticity due to multiple sclerosis, spinal cord injury, or other spinal cord disorders
60 mcg/kg/day intravenously for 3 consecutive days before and 3 consecutive days after myelotoxic therapy.
15 mg orally once daily. May increase to 30 mg once daily if needed, after at least 1 week. Maximum 30 mg/day.
Terminal elimination half-life is approximately 4.5 hours in healthy adults. In patients with renal impairment (Cr Cl <30 m L/min), half-life is prolonged up to 2-fold, requiring dose adjustment. The half-life supports once-daily dosing for 3 consecutive days before chemotherapy.
Terminal elimination half-life approximately 32 hours (range 28–40 hours); clinically relevant for once-daily dosing in chronic muscle spasm
Metabolized via proteolytic degradation; no specific CYP450 involvement.
Hepatic via deamination; primarily metabolized by monoamine oxidase B (MAO-B) to inactive metabolites.
Primarily renal; approximately 90% of the dose is excreted unchanged in urine within 24 hours via glomerular filtration and tubular secretion. Minimal biliary/fecal elimination (<5%).
Renal: approximately 40% as unchanged drug and metabolites; biliary/fecal: minimal; total clearance: 2.5 L/min
Approximately 95% bound to plasma proteins, primarily albumin.
40–45% bound to serum proteins, primarily albumin
Volume of distribution at steady state (Vd_ss) is approximately 0.2 L/kg, indicating limited extravascular distribution, consistent with a large protein-bound molecule. Does not distribute extensively into tissues.
5–8 L/kg; suggests extensive tissue distribution, including skeletal muscle
Subcutaneous administration: Absolute bioavailability is approximately 90% compared to intravenous administration. Not available orally; only given subcutaneously.
Oral: 85–95% (extended-release formulation)
No dose adjustment is recommended for renal impairment, but monitor serum creatinine.
No specific dose adjustment recommended; use with caution in severe renal impairment (Cr Cl < 30 m L/min).
No specific dose adjustment for Child-Pugh class A or B; use caution in severe impairment.
Contraindicated in Child-Pugh class C. For Child-Pugh class A or B: initiate at 15 mg once daily; do not increase dose. Use with caution.
Safety and efficacy not established; no recommended pediatric dose.
Safety and efficacy not established in pediatric patients under 12 years. For ages 12 and older, same as adult dosing.
No specific dose adjustment, but consider age-related renal and hepatic function decline.
Initiate at 15 mg once daily. Due to higher incidence of anticholinergic effects and falls, monitor closely; consider lower doses in frail elderly.
None.
None
Potential for stimulation of epithelial tumor growth (use caution in patients with non-hematologic malignancies).,Risk of allergic reactions including anaphylaxis.,May cause oral mucosal thickening and dental abnormalities.,Avoid use within 24 hours before or after myelotoxic chemotherapy.
Abrupt discontinuation may precipitate withdrawal syndrome including hallucinations, seizures, autonomic instability.,May cause sedation, dizziness, and muscle weakness; caution with activities requiring alertness.,Use with caution in patients with impaired renal function due to reduced clearance.,May exacerbate seizures in patients with epilepsy.,Avoid concomitant use with other CNS depressants.
Hypersensitivity to palifermin or any excipients.,Concurrent use within 24 hours of myelotoxic chemotherapy.
Hypersensitivity to amrix or baclofen.,Abrupt withdrawal is contraindicated; must be tapered.,Concomitant use with MAO inhibitors is contraindicated due to risk of hypertensive crisis.
No specific food interactions have been reported for KEPIVANCE. Maintain adequate nutrition and hydration as recommended by your healthcare provider.
Avoid grapefruit and grapefruit juice during treatment as they may increase cyclobenzaprine levels. Taking AMRIX with or without food does not significantly affect absorption. Alcohol should be strictly avoided as it potentiates CNS depression.
KEPIVANCE (palifermin) is a recombinant human keratinocyte growth factor. No adequate and well-controlled studies in pregnant women. In animal reproduction studies, palifermin was not teratogenic in rats or rabbits at doses up to 100 mg/kg/day (IV), which produced exposures approximately 40 and 80 times the human exposure at the recommended clinical dose of 60 mcg/kg/day, based on AUC. However, there are no human data. Risk in first trimester: unknown; second and third trimesters: unknown.
Cyclobenzaprine (AMRIX) is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, but adequate well-controlled studies in pregnant women are lacking. Use only if clearly needed. First trimester: no specific teratogenic effects documented; second and third trimesters: avoid near term due to potential neonatal effects (e.g., sedation, withdrawal).
It is not known whether palifermin is excreted in human milk. No data on M/P ratio. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from palifermin, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Cyclobenzaprine is excreted into human milk in small amounts. M/P ratio: not established. Use with caution in nursing mothers; monitor infant for sedation, poor feeding, or hypotonia.
No pharmacokinetic data in pregnancy. No dose adjustment recommendations are provided for pregnancy; use only if clearly needed.
No specific dose adjustments are recommended based on pharmacokinetic changes in pregnancy; however, due to potential for increased clearance, lowest effective dose should be used. Avoid use during labor and delivery due to potential neonatal depression.
KEPIVANCE (palifermin) is a recombinant human keratinocyte growth factor used to decrease the incidence and duration of severe oral mucositis in patients with hematologic malignancies undergoing myelotoxic therapy requiring hematopoietic stem cell support. Administer as a 3-day course of 60 mcg/kg/day IV bolus for 3 consecutive days before and 3 consecutive days after myelotoxic therapy. Must be given at least 24 hours before and after chemotherapy; do not administer within 24 hours of chemotherapy due to risk of enhanced cytotoxicity. Monitor for skin reactions, oral/perioral edema, and taste alteration. Contraindicated in patients with known hypersensitivity to E. coli-derived proteins.
AMRIX (cyclobenzaprine extended-release) should not be used longer than 2-3 weeks due to lack of evidence for efficacy in muscle spasm beyond that period. It has significant anticholinergic effects; avoid in patients with glaucoma, urinary retention, or those taking MAOIs. Do not crush or chew capsules; administer once daily at same time. Onset of action is delayed compared to immediate-release cyclobenzaprine.
KEPIVANCE reduces the severity and duration of mouth sores caused by high-dose chemotherapy.,It is given as a short intravenous infusion once daily for 3 days before and 3 days after your chemotherapy.,You may experience swelling of the mouth, tongue, or lips; skin rash; or changes in taste. Report these to your healthcare team.,Do not receive KEPIVANCE within 24 hours before or after chemotherapy.,Inform your doctor if you have any allergies, especially to E. coli-derived products.
Take AMRIX exactly once daily at the same time each day; do not crush, chew, or open the capsule.,Avoid alcohol and other CNS depressants (e.g., benzodiazepines, opioids) as they increase the risk of severe drowsiness and dizziness.,Do not drive or operate heavy machinery until you know how AMRIX affects you; it may cause drowsiness, dizziness, or blurred vision.,Contact your healthcare provider if you experience symptoms of serotonin syndrome (e.g., agitation, hallucinations, rapid heart rate, fever, muscle stiffness, nausea, diarrhea).,Do not use AMRIX for longer than 2-3 weeks unless specifically directed by your doctor; prolonged use is not recommended.,Inform your doctor if you have a history of urinary retention, glaucoma, thyroid disorders, heart problems, or liver disease.,If you miss a dose, take it as soon as you remember unless it is almost time for your next dose; do not double the dose.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about KEPIVANCE vs AMRIX, answered by our medical review team.
KEPIVANCE is a Growth Factor that works by Kepivance (palifermin) is a recombinant human keratinocyte growth factor (KGF) that binds to the KGF receptor, a splice variant of fibroblast growth factor receptor 2 (FGFR2b), stimulating proliferation, differentiation, and migration of epithelial cells, including those in the gastrointestinal tract.. AMRIX is a Muscle Relaxant that works by Centrally acting muscle relaxant; it is the R-enantiomer of baclofen. Agonist at GABA-B receptors in the spinal cord, leading to inhibition of monosynaptic and polysynaptic spinal reflexes, thereby reducing muscle spasticity.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between KEPIVANCE and AMRIX 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 KEPIVANCE is: 60 mcg/kg/day intravenously for 3 consecutive days before and 3 consecutive days after myelotoxic therapy.. The standard adult dose of AMRIX is: 15 mg orally once daily. May increase to 30 mg once daily if needed, after at least 1 week. Maximum 30 mg/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 KEPIVANCE and AMRIX 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. KEPIVANCE is classified as Category C. KEPIVANCE (palifermin) is a recombinant human keratinocyte growth factor. No adequate and well-controlled studies in pregnant women. In animal reproduction studies, palifermin was . AMRIX is classified as Category C. Cyclobenzaprine (AMRIX) is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, but adequate well-controlled studies in pregnant women are lacki. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.