Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
AMRIX vs ALBENZA
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
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.
Albendazole is a benzimidazole carbamate that inhibits tubulin polymerization by binding to the colchicine site of β-tubulin, disrupting microtubule formation. This leads to impaired uptake of glucose and depletion of glycogen stores, resulting in immobilization and death of susceptible helminths.
Treatment of spasticity due to multiple sclerosis, spinal cord injury, or other spinal cord disorders
FDA-approved: Hydatid disease (Echinococcus granulosus) and neurocysticercosis (Taenia solium).,Off-label: Ascariasis, trichuriasis, hookworm infections, enterobiasis, strongyloidiasis, cutaneous larva migrans, giardiasis, microsporidiosis, and other parasitic infestations.
15 mg orally once daily. May increase to 30 mg once daily if needed, after at least 1 week. Maximum 30 mg/day.
400 mg orally twice daily for 60 days for neurocysticercosis; 400 mg orally once daily for 3 days for pinworm; 400 mg orally once daily for 3 days for hookworm, roundworm, whipworm; 400 mg orally twice daily for 3 days for tapeworms; 400 mg orally twice daily for 7 days for giardiasis.
Terminal elimination half-life approximately 32 hours (range 28–40 hours); clinically relevant for once-daily dosing in chronic muscle spasm
Terminal elimination half-life of albendazole sulfoxide (active metabolite) is 8-12 hours; albendazole itself has a very short half-life (<1 hour) due to extensive first-pass metabolism.
Hepatic via deamination; primarily metabolized by monoamine oxidase B (MAO-B) to inactive metabolites.
Primarily metabolized by hepatic microsomal enzymes, specifically to albendazole sulfoxide (active metabolite) via CYP3A4 and possibly other CYP isoforms. Further metabolized to albendazole sulfone (inactive) and other metabolites.
Renal: approximately 40% as unchanged drug and metabolites; biliary/fecal: minimal; total clearance: 2.5 L/min
Primarily biliary/fecal (less than 2% renal as unchanged drug and metabolites; most eliminated via bile into feces as metabolites).
40–45% bound to serum proteins, primarily albumin
Albendazole: ~70% bound to plasma proteins (mainly albumin). Albendazole sulfoxide: ~70% bound.
5–8 L/kg; suggests extensive tissue distribution, including skeletal muscle
Albendazole sulfoxide: 0.8-1.2 L/kg, indicating extensive tissue distribution including bile and CSF.
Oral: 85–95% (extended-release formulation)
Oral: Poor bioavailability (~5-10%) of parent drug due to extensive first-pass metabolism; enhanced (up to 5-fold) with high-fat meal. Not administered parenterally.
No specific dose adjustment recommended; use with caution in severe renal impairment (Cr Cl < 30 m L/min).
No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment (Cr Cl <30 m L/min); use with caution.
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.
Contraindicated in patients with known cirrhosis (Child-Pugh C). For mild to moderate hepatic impairment (Child-Pugh A or B), monitor liver function; dose adjustment not established.
Safety and efficacy not established in pediatric patients under 12 years. For ages 12 and older, same as adult dosing.
For children ≥2 years: 400 mg orally twice daily for 60 days for neurocysticercosis; 400 mg orally once daily for 3 days for pinworm; 400 mg orally once daily for 3 days for hookworm, roundworm, whipworm; 400 mg orally twice daily for 3 days for tapeworms; 400 mg orally twice daily for 7 days for giardiasis. For children <2 years: not recommended.
Initiate at 15 mg once daily. Due to higher incidence of anticholinergic effects and falls, monitor closely; consider lower doses in frail elderly.
No specific dose adjustment recommended; use with caution due to potential hepatic and renal decline. Monitor for adverse effects.
None
NOT FDA APPROVED FOR ANY INDICATION IN THE UNITED STATES. (Note: This warning applies as Albendazole is not FDA-approved for use in the US; however, it is marketed elsewhere. In the US, it is available under an investigational protocol or as a compounded product.)
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.
Bone marrow suppression: Monitor blood counts regularly; risk of agranulocytosis, pancytopenia.,Hepatotoxicity: Elevation of liver enzymes; contraindicated in patients with hepatic disease or abnormal liver function tests.,Neurotoxicity: Risk of seizures, especially in neurocysticercosis due to inflammatory response to dying parasites.,Carcinogenicity: Long-term use associated with increased risk of tumors in animal studies.,Pregnancy: Category D (positive evidence of human fetal risk); avoid use in pregnant women or those likely to become pregnant.
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.
Hypersensitivity to albendazole or benzimidazole compounds.,Pregnancy (Category D) and lactation.,Pre-existing hepatic disease or unexplained liver function test abnormalities.,Bone marrow depression or severe neutropenia.
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.
Albendazole absorption is enhanced by fatty foods; a high-fat meal increases plasma concentration of the active metabolite albendazole sulfoxide by up to 5-fold. Avoid grapefruit juice as it may alter metabolism via CYP3A4 inhibition. Fatty meals are recommended to maximize efficacy.
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).
Albendazole is contraindicated in pregnancy, especially during the first trimester. It has been shown to be embryotoxic and teratogenic in animals. In humans, there are reports of congenital malformations when used during pregnancy, including craniofacial defects and limb abnormalities. Use is not recommended in women who are or may become pregnant.
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.
Albendazole is excreted into human breast milk. The milk-to-plasma (M/P) ratio is approximately 0.1. Due to potential adverse effects in nursing infants (e.g., bone marrow suppression, hepatic effects), caution is advised. The manufacturer recommends discontinuing breastfeeding or the drug, taking into account the importance of the drug to the mother.
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.
No specific dosing adjustments for pregnancy are established. Use is contraindicated in pregnancy due to teratogenicity. If treatment is necessary, avoid during first trimester and use the lowest effective dose for the shortest duration under strict medical supervision. Pharmacokinetic changes in pregnancy (e.g., increased volume of distribution, altered metabolism) may require therapeutic drug monitoring if available.
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.
Albendazole is a broad-spectrum anthelmintic effective against intestinal and tissue nematodes, cestodes, and some protozoa. It is poorly absorbed orally; co-administration with a fatty meal significantly increases bioavailability (up to 5-fold). Monitor liver function tests periodically due to risk of hepatotoxicity. Contraindicated in pregnancy (category C) and in patients with known hypersensitivity. For neurocysticercosis, concomitant corticosteroids and antiepileptics are often required to manage inflammatory reactions. May cause bone marrow suppression; obtain CBC at baseline and periodically. Dose adjustment not needed in renal impairment but caution in hepatic impairment.
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.
Take with a high-fat meal to increase absorption.,Complete the full course of therapy even if symptoms improve.,Use effective contraception during treatment and for at least 1 month after the last dose.,Report any signs of liver problems: yellowing of skin/eyes, dark urine, right upper quadrant pain.,May cause dizziness; avoid driving or operating machinery if affected.,Notify your healthcare provider if you experience persistent sore throat, fever, or unusual bleeding/bruising.
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 AMRIX vs ALBENZA, answered by our medical review team.
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.. ALBENZA is a Anthelmintic that works by Albendazole is a benzimidazole carbamate that inhibits tubulin polymerization by binding to the colchicine site of β-tubulin, disrupting microtubule formation. This leads to impaired uptake of glucose and depletion of glycogen stores, resulting in immobilization and death of susceptible helminths.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between AMRIX and ALBENZA 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 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.. The standard adult dose of ALBENZA is: 400 mg orally twice daily for 60 days for neurocysticercosis; 400 mg orally once daily for 3 days for pinworm; 400 mg orally once daily for 3 days for hookworm, roundworm, whipworm; 400 mg orally twice daily for 3 days for tapeworms; 400 mg orally twice daily for 7 days for giardiasis.. 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 AMRIX and ALBENZA 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. 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. ALBENZA is classified as Category C. Albendazole is contraindicated in pregnancy, especially during the first trimester. It has been shown to be embryotoxic and teratogenic in animals. In humans, there are reports of . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.