BETAPAR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BETAPAR (BETAPAR).
Beta-2 adrenergic receptor agonist that stimulates adenylyl cyclase, increasing cAMP levels, leading to bronchodilation.
| Metabolism | Metabolized primarily by CYP3A4, with minor contributions from CYP2D6 and CYP2C19. |
| Excretion | Renal excretion of unchanged drug accounts for 60-70% of elimination; biliary/fecal excretion accounts for 20-30%; the remainder undergoes hepatic metabolism. |
| Half-life | Terminal elimination half-life is 3-5 hours in patients with normal renal function; prolonged to 10-20 hours in severe renal impairment (CrCl <30 mL/min). |
| Protein binding | 85-90% bound to albumin. |
| Volume of Distribution | Vd approximately 0.8-1.2 L/kg, indicating distribution into total body water and some tissue binding. |
| Bioavailability | Oral bioavailability is 70-80% due to first-pass metabolism; intravenous bioavailability is 100%. |
| Onset of Action | Oral: 30-60 minutes; intravenous: 2-5 minutes. |
| Duration of Action | Oral: 6-8 hours; intravenous: 4-6 hours. Duration may be extended in renal impairment or with sustained-release formulations. |
| Molecular Weight | 392.47 |
| Action Class | Glucocorticoids |
| Brand Substitutes | Betanat 4mg Injection, Betamax 4mg Injection, Nbet 4mg Injection, Betjec 4mg Injection, Betavol 4mg Injection |
Initial: 25 mg orally twice daily; may increase gradually to 100 mg twice daily based on tolerance and response.
| Dosage form | TABLET |
| Renal impairment | No dosage adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment (CrCl <30 mL/min); use with caution. |
| Liver impairment | Contraindicated in patients with severe hepatic impairment (Child-Pugh class C). For moderate impairment (Child-Pugh class B), use with caution and consider starting at 25 mg once daily. |
| Pediatric use | Safety and efficacy not established in pediatric patients; use not recommended. |
| Geriatric use | Start at 25 mg once daily; increase slowly based on tolerability. Monitor renal function and vital signs closely. |
| 1st trimester | Not recommended; animal studies show risk and no adequate human studies. |
| 2nd trimester | Not recommended; risk of fetal bradycardia and hypoglycemia. |
| 3rd trimester | Not recommended; may cause fetal bradycardia, hypoglycemia, and low birth weight. |
Clinical note
Comprehensive clinical and safety monograph for BETAPAR (BETAPAR).
| Placental transfer | Betamethasone crosses the placenta; salicylic acid may also cross, especially with topical application on large areas or broken skin. |
| Breastfeeding | BETAPAR (a combination of betamethasone and salicylic acid) should not be used during breastfeeding due to potential systemic absorption of salicylates, which have been associated with Reye's syndrome in infants. Betamethasone is excreted in breast milk and could suppress infant adrenal function. |
■ FDA Black Box Warning
Long-acting beta-2 agonists (LABA) increase the risk of asthma-related death. Therefore, LABA should only be used as add-on therapy for patients not adequately controlled on inhaled corticosteroids.
| Serious Effects |
Hypersensitivity to any componentFungal, viral, or tuberculous skin lesionsAcute impetigoPerioral dermatitisRosacea
| Precautions | Asthma-related death; paradoxical bronchospasm; cardiovascular effects (increased heart rate, hypertension); hypokalemia; hyperglycemia; immediate hypersensitivity reactions. |
| Food/Dietary | No significant food interactions; however, avoid excessive alcohol intake as it may enhance hypotensive effects. |
Loading safety data…
| Lactation Rating |
| Avoid |
| Teratogenic Risk | Betapar (betamethasone) is a corticosteroid. In first trimester: association with oral clefts (odds ratio ~1.3-3.3) based on observational studies. Second/third trimester: risk of fetal growth restriction, adrenal suppression, and potential long-term neurodevelopmental effects. Use only if maternal benefit outweighs risks. |
| Fetal Monitoring | Monitor maternal blood pressure, blood glucose, and signs of infection. Fetal monitoring includes ultrasound for growth restriction, amniotic fluid assessment, and nonstress test/biophysical profile if prolonged therapy. Neonatal monitoring for adrenal insufficiency after delivery. |
| Fertility Effects | Betamethasone may suppress hypothalamic-pituitary-adrenal axis and gonadotropin secretion, potentially causing menstrual irregularities and temporary fertility impairment. No evidence of permanent infertility. |
| Clinical Pearls |
| BETAPAR (betaxolol) is a cardioselective beta-1 blocker used for hypertension and glaucoma. Due to beta-1 selectivity, it may be safer in patients with asthma or COPD compared to non-selective beta-blockers, but caution is still advised. Intraocular formulation reduces systemic absorption; however, monitor for bradycardia and heart block in susceptible patients. Abrupt withdrawal may exacerbate angina or hypertension. |
| Patient Advice | Do not stop taking this medication suddenly; talk to your doctor before discontinuing. · Take as prescribed, usually once daily, with or without food. · Monitor for signs of slow heart rate (dizziness, fainting) or breathing difficulty. · If using eye drops, apply pressure to the tear duct for 1 minute after instillation to minimize systemic absorption. · Inform all healthcare providers you are taking betaxolol. |