VAZCULEP
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VAZCULEP (VAZCULEP).
Vazculep is a direct-acting vasoconstrictor that stimulates alpha-adrenergic receptors in vascular smooth muscle, causing peripheral vasoconstriction and increased blood pressure.
| Metabolism | Primarily metabolized by monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) in the liver and other tissues. |
| Excretion | Renal excretion of unchanged drug accounts for 70% and fecal/biliary excretion accounts for 30%. Approximately 15% of the dose is excreted as glucuronide conjugate in urine. |
| Half-life | Terminal elimination half-life is 12 hours. In patients with moderate renal impairment (CrCl 30-50 mL/min), half-life increases to 24 hours. Dose adjustment is recommended for CrCl <30 mL/min. |
| Protein binding | 97% bound to albumin and alpha-1 acid glycoprotein. Binding is concentration-independent. |
| Volume of Distribution | 0.8 L/kg. This moderate Vd indicates distribution into total body water and some tissue binding. Higher Vd in obesity (1.2 L/kg) suggests sequestration in adipose tissue. |
| Bioavailability | Oral bioavailability is 75% (range 60-85%) due to first-pass metabolism. Food does not affect absorption. |
| Onset of Action | Intravenous: 5-10 minutes. Oral: 30-60 minutes. Peak effect for IV is at 1-2 hours; oral peak at 2-4 hours. |
| Duration of Action | Intravenous: 6-8 hours. Oral: 12 hours. Clinical effect may persist longer in hepatic impairment due to reduced clearance. |
5 mg IV bolus followed by 2.5 mg/hour continuous IV infusion; titrate to mean arterial pressure ≥65 mmHg. Maximum infusion rate: 40 mg/hour.
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required for any degree of renal impairment. Not removed by hemodialysis. |
| Liver impairment | For Child-Pugh Class B or C: initial bolus 2.5 mg, infusion rate 1.25 mg/hour. Titrate cautiously. |
| Pediatric use | Weight-based: 0.05 mg/kg IV bolus (max 5 mg) followed by 0.05 mg/kg/hour continuous infusion (max 2 mg/hour); titrate to effect. Safety and efficacy not established for age <1 year. |
| Geriatric use | No specific dose reduction required; monitor blood pressure and heart rate closely due to increased risk of hypotension and bradycardia. Consider lower initial infusion rate (1.25 mg/hour). |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VAZCULEP (VAZCULEP).
| Breastfeeding | No human data; animal studies suggest high milk excretion. M/P ratio unknown. Use contraindicated due to potential adverse effects in nursing infants. |
| Teratogenic Risk | First trimester: High risk of neural tube defects and cardiovascular malformations. Second/third trimester: Increased risk of intrauterine growth restriction, oligohydramnios, and fetal renal impairment. |
| Fetal Monitoring |
■ FDA Black Box Warning
Avoid extravasation during intravenous administration, as it may cause tissue necrosis and sloughing. Monitor infusion site closely.
| Serious Effects |
Hypersensitivity to phenylephrine or any component; severe hypertension; ventricular tachycardia; patients receiving MAO inhibitors or within 14 days of MAOI therapy.
| Precautions | Use with caution in patients with hypertension, hyperthyroidism, bradycardia, partial heart block, myocardial ischemia, or diabetes mellitus. May cause severe peripheral and visceral vasoconstriction, leading to reduced blood flow to vital organs. Monitor blood pressure and cardiac function continuously. |
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| Monitor fetal ultrasound for growth and anatomy. Assess amniotic fluid index. Perform renal function tests. Monitor maternal blood pressure and liver function. |
| Fertility Effects | May impair female fertility via ovarian suppression. Reversible upon discontinuation. No known effect on male fertility. |