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Muscle relaxant/opioid combination/Discontinued

ORLEX HC

ORLEX HC

Clinical safety rating

caution

Comprehensive clinical and safety monograph for ORLEX HC (ORLEX HC).


Mechanism of Action

Hydrocodone is a full opioid agonist with relative selectivity for mu-opioid receptors, though it can bind to other opioid receptors at higher doses. Its analgesic effects are mediated via modulation of nociceptive pathways in the CNS. Homatropine is an anticholinergic agent that reduces excessive respiratory tract secretions by blocking muscarinic receptors.

What the body does with it

MetabolismHydrocodone is metabolized primarily via CYP3A4 and CYP2D6 to hydromorphone (active) and norhydrocodone (inactive). Homatropine is metabolized via hepatic enzymes, exact pathways not well characterized.
ExcretionORLEX HC contains Hydrocodone and Homatropine. Hydrocodone: primarily renal elimination (~85% as metabolites, ~5% unchanged). Homatropine: biliary/fecal (up to 70%) and renal (30%).
Half-lifeHydrocodone: terminal half-life 3.8-5.6 hours (mean ~4.5 h) in adults; clinically, steady state in ~1-2 days. Homatropine: ~8-12 hours.
Protein bindingHydrocodone: ~20-30% bound, primarily to albumin. Homatropine: ~15% bound to albumin.
Volume of DistributionHydrocodone: 3.3-4.7 L/kg (extensive tissue distribution). Homatropine: ~1-2 L/kg.
BioavailabilityHydrocodone: oral bioavailability ~50-70% (first-pass effect). Homatropine: oral bioavailability ~10-20% (poor absorption and first-pass).
Onset of ActionHydrocodone: oral onset 10-30 minutes. Homatropine: oral onset 30-60 minutes.
Duration of ActionHydrocodone: 4-6 hours (analgesic). Homatropine: up to 6 hours (anticholinergic).
Molecular Weight534.5

Classification & Brands

Dosing & administration

1 capsule (hydrocortisone 5 mg, phenylephrine 5 mg, chlorpheniramine 4 mg) orally every 4-6 hours as needed, not exceeding 6 capsules per day.

Dosage formSOLUTION/DROPS
Renal impairmentNo specific dose adjustment recommended. Use with caution in severe renal impairment (eGFR <30 mL/min/1.73m²) due to risk of phenylephrine accumulation and hypertension.
Liver impairmentNo specific dose adjustment recommended. Use with caution in severe hepatic impairment (Child-Pugh Class C) due to potential increased exposure to hydrocortisone and chlorpheniramine.
Pediatric useNot recommended for children under 12 years. For ages 12-17: 1 capsule orally every 4-6 hours, max 6 capsules/day.
Geriatric useInitiate at lowest effective dose (e.g., 1 capsule every 6 hours) and monitor for anticholinergic effects (chlorpheniramine) and hypertension (phenylephrine). Avoid in patients with uncontrolled hypertension or narrow-angle glaucoma.

Use during pregnancy

1st trimesterAvoid use; potential teratogenic effects with prolonged use.
2nd trimesterUse only if clearly needed; may cause adrenal suppression in fetus.
3rd trimesterAvoid; risk of neonatal adrenal suppression and premature delivery.

Clinical note

Comprehensive clinical and safety monograph for ORLEX HC (ORLEX HC).

Placental transferCrosses placenta; degree depends on corticosteroid potency and dose.
BreastfeedingExcreted in breast milk; may suppress infant adrenal function. Use only if benefit outweighs risk.
Lactation RatingL3 (Moderately Safe)
Teratogenic RiskFirst trimester: Cleft lip/palate, neural tube defects; late pregnancy: premature closure of ductus arteriosus, oligohydramnios, fetal renal impairment; third trimester: neonatal adrenal suppression.
Fetal MonitoringMonitor fetal growth and amniotic fluid volume via ultrasound; assess ductus arteriosus flow in third trimester; maternal blood pressure and glucose.
Fertility EffectsNo proven effect on fertility; chronic use may impair ovulation.

Warnings & precautions

■ FDA Black Box Warning

Risks of addiction, abuse, misuse; life-threatening respiratory depression; accidental ingestion (especially fatal in children); neonatal opioid withdrawal syndrome with prolonged use during pregnancy; risks from concomitant use with benzodiazepines or other CNS depressants; risk of medication errors due to multiple strengths and formulations.

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to any componentSystemic fungal infectionsAdministration of live vaccines

Clinical Precautions

PrecautionsRespiratory depression; drug dependence and abuse; head injury/increased intracranial pressure; acute abdominal conditions; concurrent use with CNS depressants; elderly/debilitated patients; severe renal or hepatic impairment; hypothyroidism; Addison's disease; prostatic hyperplasia; urinary retention; pregnancy; lactation.
Food/DietaryNo clinically significant food interactions.

Clinical Tips & Counseling

Clinical PearlsORLEX HC (hydrocortisone/neomycin/polymyxin B) is an otic suspension. Use for acute otitis externa when the tympanic membrane is intact. Avoid if perforation is suspected, as neomycin is ototoxic. Shake well before use. Contraindicated in viral or fungal infections. Monitor for sensitization to neomycin.
Patient AdviceInstill 4 drops into the affected ear(s) 3-4 times daily. · Keep the ear dropper bottle upright to avoid contamination. · Lie on your side for 5 minutes after instillation to allow medication to coat the ear canal. · Complete the full course even if symptoms improve. · Do not share the medication with others. · Report any signs of allergic reaction (rash, itching, swelling) to your doctor. · Do not use if you have a perforated eardrum or ear tube.

ORLEX HC Interactions

Loading safety data…

This overview is compiled from peer-reviewed clinical sources and FDA labeling. It's here to support — not replace — clinical judgment. Always verify dosing against your institution's current protocols before prescribing.

On this page

Mechanism of ActionDosing & administrationUse during pregnancyWarnings & precautionsDrug interactions

External sources

DailyMed (NIH) PubMed OpenFDA