METIPRANOLOL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for METIPRANOLOL (METIPRANOLOL).
Metipranolol is a non-selective beta-adrenergic receptor antagonist that blocks beta-1 and beta-2 receptors. It reduces intraocular pressure by decreasing aqueous humor production.
| Metabolism | Metipranolol is metabolized in the liver primarily via deacetylation to its active metabolite, desacetylmetipranolol. Further metabolism involves glucuronidation and sulfation. |
| Excretion | Renal: 70-80% as unchanged drug and metabolites; biliary/fecal: 20-30% |
| Half-life | 3-4 hours; in renal impairment may extend to 8-10 hours |
| Protein binding | 78-96% bound to albumin |
| Volume of Distribution | 3-4 L/kg; indicates extensive extravascular distribution |
| Bioavailability | Oral: 50-60% due to first-pass metabolism; ophthalmic: 10-20% systemic absorption |
| Onset of Action | Oral: 1-2 hours; ophthalmic: 30 minutes (IOP reduction) |
| Duration of Action | Oral: 12-24 hours (beta-blockade); ophthalmic: 24 hours (IOP reduction) |
Ophthalmic solution: 0.1% to 0.3% instilled into the conjunctival sac one to two times daily. Oral: 10 mg to 20 mg twice daily; maximum 60 mg daily.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No specific guidelines; use with caution in severe renal impairment (GFR <30 mL/min). Monitor for bradycardia and hypotension. |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose by 50% or extend dosing interval. Child-Pugh C: Use contraindicated. |
| Pediatric use | Not established for systemic use; for ophthalmic use, safety and efficacy not established in children <2 years; low concentration (0.1%) may be used cautiously in older children. |
| Geriatric use | Start at lowest effective dose; monitor for bradycardia, hypotension, and bronchospasm. Ophthalmic: use 0.1% solution initially. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for METIPRANOLOL (METIPRANOLOL).
| Breastfeeding | Metipranolol is excreted in breast milk. M/P ratio unknown. Due to potential for infant bradycardia and hypoglycemia, use with caution; monitor infant for signs of beta-blockade. |
| Teratogenic Risk | First trimester: No adequate studies; beta-blockers generally associated with fetal bradycardia and growth restriction. Second/third trimester: Risk of fetal bradycardia, hypoglycemia, and low birth weight. Avoid use if possible; if necessary, monitor fetal heart rate and growth. |
| Fetal Monitoring |
■ FDA Black Box Warning
No black box warning exists for ophthalmic use. However, systemic absorption may occur and exacerbate respiratory or cardiac conditions.
| Serious Effects |
["Hypersensitivity to metipranolol or any component of the formulation","Bronchial asthma or history of bronchospasm","Sinus bradycardia, sick sinus syndrome, or second/third-degree atrioventricular block (unless paced)","Cardiogenic shock or overt heart failure","Severe chronic obstructive pulmonary disease"]
| Precautions | ["May be absorbed systemically and exacerbate asthma or COPD due to beta-blockade","Can mask signs of hyperthyroidism (e.g., tachycardia)","May cause bradycardia or heart block in patients with pre-existing cardiac disease","Use with caution in patients with diabetes mellitus as it may mask hypoglycemic symptoms","Possibility of anaphylactic reactions in patients with history of atopy or allergy"] |
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| Maternal: Heart rate, blood pressure, and signs of bronchospasm. Fetal: Heart rate monitoring and ultrasound for growth assessment during third trimester. Neonatal: Observe for bradycardia, hypoglycemia, and respiratory depression at birth. |
| Fertility Effects | No specific data on fertility impairment in humans. Beta-blockers may theoretically affect sexual function and sperm motility, but no conclusive evidence for metipranolol. |