ORLEX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ORLEX (ORLEX).
Orlistat is a reversible inhibitor of gastric and pancreatic lipases, preventing the hydrolysis of dietary triglycerides into absorbable free fatty acids and monoglycerides. This reduces dietary fat absorption by approximately 30%.
| Metabolism | Primarily metabolized in the gastrointestinal wall and liver via hydrolysis; minimal systemic absorption. Main metabolites are M1 (4-member lactone ring hydrolysis) and M3 (M1 with a cleaved N-formyl leucine moiety). |
| Excretion | Renal: 70% (as unchanged drug and metabolites); Biliary/Fecal: 30% |
| Half-life | Terminal elimination half-life: 4-6 hours; in renal impairment, half-life can extend to >12 hours requiring dose adjustment. |
| Protein binding | 99% primarily to albumin and alpha-1-acid glycoprotein |
| Volume of Distribution | 0.15-0.2 L/kg, indicating confinement to vascular space; correlates with high protein binding. |
| Bioavailability | Oral: 90-100% (extensive absorption); no significant first-pass metabolism. |
| Onset of Action | Oral: 30-60 minutes; IV: within 5 minutes |
| Duration of Action | 4-6 hours; clinical effect parallels plasma concentration. Extended-release formulations may provide up to 12 hours. |
Orally, 1-2 tablets (5-10 mg of hydrocodone equivalent) every 4-6 hours as needed for pain; maximum 12 tablets per day.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | For GFR 30-59 mL/min: administer every 6-8 hours; GFR <30 mL/min: administer every 8-12 hours; avoid use in GFR <15 mL/min. |
| Liver impairment | Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 25%; Child-Pugh Class C: avoid use. |
| Pediatric use | Children ≥2 years: 0.1-0.2 mg/kg hydrocodone equivalent orally every 4-6 hours as needed; maximum 10 mg per dose. |
| Geriatric use | Initiate at 50% of adult dose, titrate cautiously; monitor for respiratory depression and constipation. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ORLEX (ORLEX).
| Breastfeeding | Codeine is excreted into breast milk with M/P ratio approximately 2.5. Risk of infant opioid toxicity, especially in ultra-rapid metabolizers; contraindicated in breastfeeding due to potential for infant respiratory depression and sedation. Acetaminophen is safe at low doses. |
| Teratogenic Risk | ORLEX (codeine/acetaminophen) is contraindicated in all trimesters due to risk of neonatal opioid withdrawal syndrome and acetaminophen hepatotoxicity. First trimester: limited data but no major malformations reported. Second and third trimesters: chronic use may lead to fetal dependence and neonatal abstinence syndrome. During labor, codeine may cause respiratory depression in neonate. |
■ FDA Black Box Warning
None
| Serious Effects |
["Chronic malabsorption syndrome","Cholestasis","Pregnancy (weight loss is not recommended)","Hypersensitivity to orlistat or any component"]
| Precautions | ["Hepatotoxicity (rare, but cases of severe liver injury reported)","Cholelithiasis (increased risk due to rapid weight loss)","Oxalate nephrolithiasis (increased urinary oxalate excretion)","Fat-soluble vitamin deficiency (A, D, E, K; supplementation recommended)","Gastrointestinal adverse effects (oily spotting, flatus with discharge, fecal urgency, steatorrhea)","Interaction with cyclosporine, amiodarone, and antiepileptic drugs"] |
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| Fetal Monitoring | Monitor maternal respiratory rate, sedation level, and bowel function. Fetal monitoring: nonstress test and biophysical profile if chronic use. Neonatal monitoring for withdrawal symptoms (e.g., tremors, irritability, poor feeding) for at least 48 hours after delivery. |
| Fertility Effects | No known significant effect on fertility. Animal studies show no impairment at therapeutic doses. Opioids may affect hormonal regulation but clinical data are limited. |