Dinoprostone

• Approved Indications:
• Induction of labor at or near term (≥ 37 weeks gestation) in patients with an unfavorable cervix (cervical ripening)
• Management of missed miscarriage or intrauterine fetal death in the second trimester
• Cervical ripening prior to surgical procedures such as hysteroscopy or abortion
• Off-label/Clinically Accepted Uses:
• Termination of pregnancy in certain clinical settings
• Facilitation of labor induction in cases of fetal demise or maternal indications
• Adjunct in medical management of postpartum hemorrhage (less common)

• Route: Vaginal administration (suppository, gel, insert), topical gel for cervical ripening
• Labor Induction:
• Vaginal suppository: 10 mg inserted into the posterior vaginal fornix every 6 hours, up to 2 doses
• Vaginal gel: 0.5 mg intracervical or intravaginal gel every 6 hours; maximum total dose 1.5 mg in 24 hours
• Intravaginal insert: 10 mg controlled-release insert left in place for up to 12 hours
• Second-Trimester Pregnancy Termination:
• 3 mg vaginal gel every 3–6 hours until abortion occurs or maximum dose reached
• Special Populations:
• Use with caution in patients with uterine scarring or previous cesarean section
• No specific dose adjustments for renal or hepatic impairment documented
• Administration Notes:
• Insert vaginally with patient in recumbent position
• Monitor uterine activity and fetal heart rate continuously during administration
• Remove insert or discontinue gel if excessive uterine contractions or fetal distress occurs

Dinoprostone is a synthetic form of prostaglandin E2 (PGE2), a naturally occurring prostaglandin that binds to specific prostaglandin receptors on uterine smooth muscle and cervical tissue. It promotes cervical softening and dilation by stimulating collagenase and proteoglycan activity in the cervix, facilitating cervical ripening. Additionally, dinoprostone induces uterine contractions by increasing intracellular calcium levels in myometrial cells, promoting labor onset and progression.

• Absorption: Local vaginal absorption with minimal systemic absorption
• Distribution: Limited systemic exposure; rapidly metabolized locally
• Metabolism: Rapidly metabolized by enzymatic degradation, primarily in the lungs and liver
• Half-life: Short systemic half-life, approximately 2.5 to 5 minutes due to rapid metabolism
• Elimination: Metabolites excreted primarily in urine
• Onset of Action: Uterine contractions typically begin within 30–60 minutes after vaginal administration
• Duration: Effects last up to several hours depending on formulation

• Pregnancy:
• FDA Category C — Dinoprostone is used specifically in pregnancy for labor induction and cervical ripening under medical supervision; not recommended for use in early pregnancy unless indicated (e.g., miscarriage management)
• Lactation:
• Limited data; caution advised if used postpartum during breastfeeding
• Minimal systemic absorption reduces risk to nursing infant

• Primary Class: Obstetric agent
• Subclass: Prostaglandin E2 analog

• Known hypersensitivity to dinoprostone or any component of the formulation
• Active pelvic inflammatory disease or uterine infection
• Non-reassuring fetal status where delivery is not imminent
• Previous cesarean section or major uterine surgery (relative contraindication; caution advised)
• Fetal malpresentation (e.g., transverse lie)
• Unexplained vaginal bleeding during current pregnancy
• Severe cephalopelvic disproportion

• Use only under continuous medical supervision with fetal monitoring
• Risk of uterine hyperstimulation and uterine rupture, especially in patients with uterine scars
• Monitor for excessive uterine contractions (tachysystole), fetal distress, and vaginal bleeding
• Avoid use in patients with asthma or hypersensitivity to prostaglandins due to potential bronchospasm
• Remove vaginal insert promptly if adverse events or complications occur
• Use cautiously in patients with cardiovascular or renal disease

• Common:
• Uterine contractions, cramping, pelvic pain
• Nausea, vomiting, diarrhea, fever
• Back pain
• Serious/Rare:
• Uterine hyperstimulation (tachysystole) with or without fetal heart rate abnormalities
• Uterine rupture (rare but life-threatening)
• Allergic reactions including rash and bronchospasm
• Hypotension or hypertension

• Other uterotonic agents (e.g., oxytocin) — increased risk of uterine hyperstimulation; careful monitoring required
• Nonsteroidal anti-inflammatory drugs (NSAIDs) — may antagonize prostaglandin effects and reduce efficacy
• Use with tocolytics (e.g., beta-agonists) may counteract intended effect

• Updated obstetric guidelines emphasize cautious use in women with prior cesarean delivery due to uterine rupture risk
• WHO and ACOG recommend dinoprostone as a first-line agent for cervical ripening and labor induction in appropriate candidates
• Newer formulations with controlled-release vaginal inserts provide improved safety and ease of use
• Continued emphasis on continuous fetal monitoring during administration

• Store at 2°C to 8°C (refrigerated) for vaginal inserts and gel formulations
• Protect from light and freezing
• Vaginal suppositories may be stored at room temperature if specified by manufacturer, generally 20°C to 25°C
• Keep out of reach of children
• Do not use past expiration date