ALPHALIN
Clinical safety rating
cautionComprehensive clinical and safety monograph for ALPHALIN (ALPHALIN).
ALPHALIN is an alpha-2 adrenergic receptor agonist that decreases sympathetic outflow from the central nervous system, resulting in reduced peripheral vascular resistance, decreased heart rate, and lowered blood pressure.
| Metabolism | Primarily hepatic via cytochrome P450 isoenzyme CYP2D6; metabolites are excreted renally. |
| Excretion | Renal excretion (70% unchanged); fecal/biliary (20%); metabolism (10%) |
| Half-life | Terminal half-life 12-15 hours (healthy adults); prolonged to 24-30 hours in renal impairment (CrCl <30 mL/min) |
| Protein binding | 98% bound primarily to albumin |
| Volume of Distribution | 0.3-0.5 L/kg; reflects limited extravascular distribution consistent with high protein binding |
| Bioavailability | Oral: 80-90% (first-pass metabolism ~10-20%); IM: 95-100% |
| Onset of Action | Oral: 30-60 min; IV: 5-10 min; IM: 15-30 min |
| Duration of Action | Oral: 8-12 hours; IV: 4-6 hours (dose-dependent with sustained release formulations up to 24 hours) |
| Molecular Weight | 210.23 |
500 mg orally once daily
| Dosage form | CAPSULE |
| Renal impairment | eGFR 30-59 mL/min: 250 mg orally once daily; eGFR 15-29 mL/min: 125 mg orally once daily; eGFR <15 mL/min: 125 mg orally every 48 hours |
| Liver impairment | Child-Pugh Class A: no adjustment; Child-Pugh Class B: 250 mg orally once daily; Child-Pugh Class C: 125 mg orally once daily |
| Pediatric use | 10-15 mg/kg orally once daily, not to exceed 500 mg/day |
| Geriatric use | Initiate at 250 mg orally once daily; titrate based on renal function |
| 1st trimester | Contraindicated due to teratogenicity (neural tube defects, cardiac anomalies). |
| 2nd trimester | Contraindicated due to risk of fetal growth restriction and neurodevelopmental toxicity. |
| 3rd trimester | Contraindicated due to increased risk of neonatal bleeding, kernicterus, and vitamin K deficiency. |
Clinical note
Comprehensive clinical and safety monograph for ALPHALIN (ALPHALIN).
| Placental transfer | Complete placental transfer; fetal concentrations reach maternal levels. |
| Breastfeeding | Not recommended; may cause infant toxicity (seizures, hypoglycemia) and potential adverse effects on clotting. |
| Lactation Rating | L5 (Contraindicated) |
| Teratogenic Risk | First trimester: Increased risk of neural tube defects and cardiovascular malformations; second and third trimesters: Risk of fetal growth restriction and oligohydramnios. |
| Fetal Monitoring | Monitor maternal liver function tests, renal function, and fetal ultrasound for anomalies and growth every 4 weeks. |
| Fertility Effects | May impair spermatogenesis and oogenesis, leading to reduced fertility; reversible upon discontinuation. |
■ FDA Black Box Warning
Avoid abrupt discontinuation; rapid withdrawal can cause rebound hypertension, anxiety, and, in severe cases, hypertensive encephalopathy or stroke.
| Serious Effects |
PregnancyLactationHistory of hypersensitivity to ALPHALINSevere hepatic impairmentCoagulation disorders
| Precautions | May cause sedation, dizziness, and orthostatic hypotension. Use caution in patients with cerebrovascular or cardiovascular disease. Monitor blood pressure regularly. Do not administer with other alpha-2 agonists. |
| Food/Dietary | No specific food interactions documented. However, avoid alcohol for 24 hours post-administration due to additive hypotensive effects. Grapefruit juice may potentiate alpha-blocker effects; avoid concurrent use. |
| Clinical Pearls | ALPHALIN is a high-potency alpha-blocker indicated for hypertensive emergencies. Administer as a slow IV bolus over 5 minutes to avoid severe hypotension. Monitor blood pressure every 2 minutes during infusion. Have intravenous fluids and vasopressors ready. Contraindicated in patients with known hypersensitivity, acute myocardial infarction, or history of orthostatic hypotension. |
| Patient Advice | This medication is given intravenously in a hospital setting only. · You will have continuous blood pressure monitoring during administration. · Report any dizziness, chest pain, or difficulty breathing immediately. · After treatment, rise slowly from sitting or lying to prevent fainting. · Avoid alcohol for 24 hours after treatment to prevent blood pressure drop. |
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