TRANDATE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TRANDATE (TRANDATE).
Competitive antagonist at beta-1 and beta-2 adrenergic receptors; also blocks alpha-1 adrenergic receptors, causing vasodilation.
| Metabolism | Hepatic via glucuronidation; CYP2D6 minor role. |
| Excretion | Labetalol is extensively metabolized in the liver via glucuronidation; less than 5% of the dose is excreted unchanged in urine. Approximately 55-60% of metabolites are excreted renally, and about 30% in feces via biliary secretion. |
| Half-life | Terminal elimination half-life is approximately 6-8 hours in healthy individuals, but may be prolonged in patients with hepatic impairment or severe renal dysfunction (up to 12-16 hours). |
| Protein binding | Approximately 50% bound to plasma proteins, primarily to albumin. |
| Volume of Distribution | Volume of distribution is approximately 3-4 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral bioavailability is approximately 25% (range 11-45%) due to significant first-pass hepatic metabolism. |
| Onset of Action | After oral administration, the onset of action is within 20 minutes to 2 hours. Intravenous administration produces an effect within 2-5 minutes. |
| Duration of Action | Oral administration yields a duration of 8-12 hours for beta-blockade, while intravenous effects last 2-4 hours. Clinically, dosing is typically twice daily for oral therapy or continuous infusion for IV. |
Initial: 100 mg orally twice daily, titrate to 200-400 mg twice daily; maximum 2400 mg/day. Alternatively, 20 mg IV bolus over 2 minutes, then 40-80 mg IV at 10-minute intervals as needed; IV infusion: 2 mg/min, titrate to response.
| Dosage form | TABLET |
| Renal impairment | GFR 10-50 mL/min: extend dosing interval to every 12-24 hours. GFR <10 mL/min: administer every 24-48 hours or reduce dose by 50%. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: contraindicated or use with extreme caution (e.g., 25% of normal dose). |
| Pediatric use | Oral: 1-2 mg/kg/dose twice daily; max 200 mg/dose. IV: 0.1-0.3 mg/kg/dose over 2 minutes, repeated every 10 minutes up to 2 mg/kg cumulative. |
| Geriatric use | Initiate at 100 mg orally once daily, titrate slowly; monitor for hypotension and bradycardia. Reduced renal clearance may necessitate dose adjustment. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for TRANDATE (TRANDATE).
| Breastfeeding | Excreted in breast milk (M/P ratio ~1.1). Use with caution; monitor infant for bradycardia and hypotension. American Academy of Pediatrics considers compatible but prefer alternatives. |
| Teratogenic Risk | FDA Pregnancy Category C: First trimester: Risk unknown; animal studies show fetal resorption and delayed ossification at high doses. Second/third trimester: Risk of fetal bradycardia, intrauterine growth restriction, and hypoglycemia. Avoid in preeclampsia due to neonatal risks. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
["Bronchial asthma","Cardiogenic shock","Second- or third-degree AV block","Sinus bradycardia","Overt cardiac failure","Hypersensitivity to labetalol"]
| Precautions | ["May exacerbate heart failure","Abrupt withdrawal may cause exacerbation of angina or MI","Mask symptoms of hypoglycemia","Peripheral vascular disease exacerbation","Hepatic injury risk"] |
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| Monitor maternal blood pressure and heart rate; fetal heart rate via auscultation or Doppler; ultrasound for fetal growth, amniotic fluid index, and doppler velocimetry if placental insufficiency suspected. |
| Fertility Effects | No known impairment of fertility in humans; animal studies show no significant reproductive effects. |