PROSTIN E2

Clinical safety rating: caution

Comprehensive clinical and safety monograph for PROSTIN E2 (PROSTIN E2).

How it works

Dinoprostone (PGE2) is a naturally occurring prostaglandin that stimulates uterine smooth muscle contractions and cervical ripening by binding to EP receptors, leading to increased intracellular calcium and myometrial contractility. It also promotes cervical softening through collagenase activation and glycosaminoglycan changes.

What the body does with it

Metabolism	Rapidly metabolized in the lungs, liver, and kidneys by 15-hydroxyprostaglandin dehydrogenase and prostaglandin reductase. Metabolites are excreted primarily in urine.
Excretion	Primarily metabolized in the lungs, liver, and kidneys; >90% of metabolites excreted renally, with <5% unchanged in urine; minor biliary/fecal elimination.
Half-life	Terminal elimination half-life is approximately 2-3 minutes for dinoprostone due to rapid enzymatic metabolism; clinical effects are short-lived, requiring continuous infusion for sustained action.
Protein binding	Approximately 80-90% bound to serum albumin.
Volume of Distribution	Vd is about 0.1-0.2 L/kg, indicating limited distribution primarily to extracellular fluid; consistent with rapid clearance and small tissue binding.
Bioavailability	Intravaginal: 10-20% (due to first-pass pulmonary metabolism); intracervical: low systemic absorption (minimal bioavailability); oral: <10% due to extensive first-pass metabolism.
Onset of Action	Intravaginal: onset of uterine contractions within 15-60 minutes; intracervical: cervical ripening begins within 1-3 hours; intravenous: immediate, within minutes.
Duration of Action	Intravaginal: 2-4 hours per dose; intracervical: up to 12 hours; intravenous: effects persist as long as infusion continues, dissipating within 15-30 minutes after discontinuation.

Classification & Brands

Dosing & administration

Cervical ripening: 0.5 mg (1 suppository) intravaginally; repeat every 4-6 hours if needed, up to 3 doses in 24 hours. Induction of labor: 2.5 mg (1 suppository) intravaginally every 3-5 hours, maximum 10 mg/24 hours.

Dosage form	SUPPOSITORY
Renal impairment	No specific dose adjustment required in renal impairment; use with caution in severe renal dysfunction (e.g., GFR <30 mL/min) due to potential for fluid retention.
Liver impairment	No specific dose adjustment required in hepatic impairment; use with caution in severe hepatic dysfunction (Child-Pugh class C) due to altered metabolism.
Pediatric use	Not indicated for pediatric use; no established dosing guidelines.
Geriatric use	No specific dose adjustment required; use with caution due to increased risk of uterine hyperstimulation and cardiovascular effects in older women.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for PROSTIN E2 (PROSTIN E2).

Breastfeeding	Excretion into breast milk unknown. M/P ratio not determined. Use with caution; potential for uterine contractions and adverse effects in infant. Short-term use for labor induction typically precludes breastfeeding.
Teratogenic Risk	FDA Pregnancy Category C. First trimester: No adequate human studies; animal studies suggest potential risk. Second and third trimesters: Used for cervical ripening and labor induction; risk of uterine hyperstimulation and fetal distress. Not associated with structural anomalies when used at term.

Warnings & precautions

■ FDA Black Box Warning

Should be used only by trained medical personnel in a hospital setting with immediate access to facilities for managing complications such as uterine hyperstimulation, fetal distress, and emergency cesarean section.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Known hypersensitivity to dinoprostone or other prostaglandins","Fetal distress or contraindications to vaginal delivery (e.g., cephalopelvic disproportion, abnormal fetal presentation)","Uterine scar from prior cesarean section or major uterine surgery (relative contraindication due to uterine rupture risk)","Placenta previa or unexplained vaginal bleeding","Grand multiparity (six or more previous term pregnancies)","Acute pelvic inflammatory disease"]

Clinical Precautions

Precautions

["Uterine hyperstimulation may occur, leading to fetal distress or uterine rupture, especially in patients with prior cesarean section or uterine surgery.","Monitor uterine activity, fetal heart rate, and cervical status continuously during administration.","Use with caution in patients with cardiovascular, renal, or hepatic impairment.","Risk of amniotic fluid embolism, disseminated intravascular coagulation (DIC) in missed abortion cases.","Prostaglandins may cause hypotension, bronchospasm, or pyrexia."]

Clinical Tips & Counseling

Drug interactions

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PROSTIN E2

Clinical safety rating: caution

Comprehensive clinical and safety monograph for PROSTIN E2 (PROSTIN E2).

How it works

What the body does with it

Metabolism	Rapidly metabolized in the lungs, liver, and kidneys by 15-hydroxyprostaglandin dehydrogenase and prostaglandin reductase. Metabolites are excreted primarily in urine.
Excretion	Primarily metabolized in the lungs, liver, and kidneys; >90% of metabolites excreted renally, with <5% unchanged in urine; minor biliary/fecal elimination.
Half-life	Terminal elimination half-life is approximately 2-3 minutes for dinoprostone due to rapid enzymatic metabolism; clinical effects are short-lived, requiring continuous infusion for sustained action.
Protein binding	Approximately 80-90% bound to serum albumin.
Volume of Distribution	Vd is about 0.1-0.2 L/kg, indicating limited distribution primarily to extracellular fluid; consistent with rapid clearance and small tissue binding.
Bioavailability	Intravaginal: 10-20% (due to first-pass pulmonary metabolism); intracervical: low systemic absorption (minimal bioavailability); oral: <10% due to extensive first-pass metabolism.
Onset of Action	Intravaginal: onset of uterine contractions within 15-60 minutes; intracervical: cervical ripening begins within 1-3 hours; intravenous: immediate, within minutes.
Duration of Action	Intravaginal: 2-4 hours per dose; intracervical: up to 12 hours; intravenous: effects persist as long as infusion continues, dissipating within 15-30 minutes after discontinuation.

Classification & Brands

Dosing & administration

Dosage form	SUPPOSITORY
Renal impairment	No specific dose adjustment required in renal impairment; use with caution in severe renal dysfunction (e.g., GFR <30 mL/min) due to potential for fluid retention.
Liver impairment	No specific dose adjustment required in hepatic impairment; use with caution in severe hepatic dysfunction (Child-Pugh class C) due to altered metabolism.
Pediatric use	Not indicated for pediatric use; no established dosing guidelines.
Geriatric use	No specific dose adjustment required; use with caution due to increased risk of uterine hyperstimulation and cardiovascular effects in older women.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for PROSTIN E2 (PROSTIN E2).

Breastfeeding	Excretion into breast milk unknown. M/P ratio not determined. Use with caution; potential for uterine contractions and adverse effects in infant. Short-term use for labor induction typically precludes breastfeeding.
Teratogenic Risk	FDA Pregnancy Category C. First trimester: No adequate human studies; animal studies suggest potential risk. Second and third trimesters: Used for cervical ripening and labor induction; risk of uterine hyperstimulation and fetal distress. Not associated with structural anomalies when used at term.