PROSTIN F2 ALPHA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PROSTIN F2 ALPHA (PROSTIN F2 ALPHA).
Prostaglandin F2 alpha receptor agonist; stimulates uterine smooth muscle contractions and causes luteolysis.
| Metabolism | Rapidly metabolized in the lungs, liver, and kidneys via 15-hydroxyprostaglandin dehydrogenase and subsequent beta-oxidation. |
| Excretion | Primarily renal (90%) as metabolites, with 5% biliary/fecal. Unchanged drug excretion <1%. |
| Half-life | Terminal elimination half-life 5–10 minutes; rapid clearance due to pulmonary metabolism. |
| Protein binding | ~50% bound to albumin. |
| Volume of Distribution | 0.2–0.5 L/kg; small Vd indicates limited extravascular distribution. |
| Bioavailability | Intramuscular: ~100%; Vaginal: variable, ~20–50% due to first-pass metabolism; Oral: extremely low (<1%) due to extensive first-pass inactivation. |
| Onset of Action | Intravenous: 1–2 minutes; Intramuscular: 15–30 minutes; Intra-amniotic: 15–30 minutes; Vaginal: 30–60 minutes. |
| Duration of Action | Intravenous: 10–20 minutes; Intramuscular: 2–3 hours; Intra-amniotic: 6–12 hours; clinical effect lasts until uterine evacuation. |
5-10 mg intramuscular injection every 12-24 hours for induction of labor; 250-500 mcg intramuscular injection every 1-2 hours for postpartum hemorrhage.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment required; use with caution in severe renal impairment due to decreased drug clearance. |
| Liver impairment | No specific dose adjustment required; monitor for adverse effects in patients with significant hepatic impairment. |
| Pediatric use | Not approved for pediatric use; safety and efficacy not established. |
| Geriatric use | Use with caution; consider reduced dose due to potential increased sensitivity and comorbidities. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PROSTIN F2 ALPHA (PROSTIN F2 ALPHA).
| Breastfeeding | No data on excretion into breast milk. Because of its abortifacient and uterine-stimulating properties, use during breastfeeding is contraindicated. M/P ratio not determined. |
| Teratogenic Risk | Pregnancy Category X. Prostin F2 alpha (dinoprost) is an abortifacient used to terminate pregnancy. It causes uterine contractions and fetal expulsion. There is no indication for use during pregnancy due to its abortifacient properties. Fetal death occurs if administered during pregnancy. |
| Fetal Monitoring |
■ FDA Black Box Warning
Not for use in pregnant patients with intact fetal membranes (if used for abortion, requires membrane rupture). Acute hypersensitivity reactions may occur. Use only in hospital settings with emergency resuscitation equipment.
| Serious Effects |
Hypersensitivity to dinoprost tromethamine; acute pelvic inflammatory disease; undiagnosed vaginal bleeding; severe asthma; severe cardiovascular disease; when fetal viability is desired (unless for termination).
| Precautions | May cause bronchospasm (use caution in asthma), hypertension, seizures, cardiac arrhythmias. Monitor uterine activity and fetal status. Use with caution in patients with cardiovascular disease, epilepsy, or uterine scarring. |
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| Monitor uterine activity, fetal heart rate (if fetus is viable), maternal blood pressure, temperature, and signs of bronchospasm. Continuous monitoring during administration is required due to potential for uterine hypertonus or rupture. |
| Fertility Effects | May temporarily disrupt menstrual cycle and ovulation due to induced abortion. No long-term fertility impairment reported with therapeutic use, but intended for termination of pregnancy. |