PRISCOLINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PRISCOLINE (PRISCOLINE).
Priscoline (tolazoline) is a competitive alpha-adrenergic receptor antagonist; also has direct vasodilatory and histamine-like effects, leading to peripheral vasodilation and decreased peripheral vascular resistance.
| Metabolism | Hepatic metabolism via N-acetylation and N-oxidation; primarily excreted unchanged in urine and via metabolism. |
| Excretion | Primarily renal excretion of unchanged drug (approximately 90%); minor fecal excretion (<10%). |
| Half-life | Terminal elimination half-life is approximately 3-4 hours in adults; prolonged in renal impairment. |
| Protein binding | 30-40% bound to plasma proteins. |
| Volume of Distribution | Approximately 1.0 L/kg, indicating extensive distribution into tissues. |
| Bioavailability | Oral: 10-20% due to extensive first-pass metabolism; Intramuscular: 90-100%. |
| Onset of Action | Intravenous: 1-2 minutes; Intramuscular: 15-30 minutes; Oral: 15-30 minutes. |
| Duration of Action | Intravenous: 10-30 minutes; Intramuscular: 30-60 minutes; Oral: 2-4 hours. |
10-50 mg subcutaneously or intramuscularly every 4-6 hours; intravenous administration (10 mg slow IV push) reserved for acute vasospastic episodes.
| Dosage form | INJECTABLE |
| Renal impairment | GFR 10-50 mL/min: reduce dose by 25-50%; GFR <10 mL/min: contraindicated. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce starting dose by 50%; Child-Pugh C: avoid use. |
| Pediatric use | 0.5-2 mg/kg subcutaneously or intramuscularly every 4-6 hours; maximum single dose 50 mg. |
| Geriatric use | Initiate at the low end of adult dosing (10 mg) due to increased sensitivity and risk of hypotension; monitor renal function and adjust accordingly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PRISCOLINE (PRISCOLINE).
| Breastfeeding | Excretion in human milk unknown. Not recommended during breastfeeding due to potential for cardiovascular effects in the infant. M/P ratio not available. |
| Teratogenic Risk | First trimester: No adequate human studies; animal studies not available. Potential fetal harm unknown. Second and third trimesters: May cause transient neonatal hypotension, bradycardia, or cyanosis if administered near term. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to tolazoline; known or suspected myocardial infarction; coronary insufficiency; peptic ulcer disease; concurrent use with vasopressors (e.g., epinephrine) due to risk of severe hypotension or paradoxical hypertension.
| Precautions | Hypotension, tachycardia, arrhythmias, myocardial infarction, gastrointestinal bleeding, renal impairment, and fluid retention. Use caution in patients with coronary artery disease, peptic ulcer disease, or renal failure. |
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| Monitor maternal blood pressure, heart rate, and ECG during infusion. Fetal heart rate monitoring recommended during labor if drug used for hypertensive crisis. |
| Fertility Effects | No specific data on fertility impairment in humans. Animal studies not available. |