Home Drug Guide Misoprostol

Drug Guide

Generic Name

Misoprostol

Brand Names Cytotec

Classification

Therapeutic: Gastrointestinal cytoprotective agent, abortifacient

Pharmacological: Prostaglandin E1 analog

FDA Approved Indications

Prevention of gastric ulcers caused by NSAIDs
Medical termination of pregnancy
Labor induction

Mechanism of Action

Misoprostol is a synthetic prostaglandin E1 analog that stimulates prostaglandin receptors, increasing mucus and bicarbonate secretion in the stomach, thereby protecting the gastric mucosa. It also causes cervical softening and uterine contractions, used in obstetric indications.

Dosage and Administration

Adult: Varies by indication; for gastric protection, 200 mcg 4 times daily with food. For abortion, 800 mcg inserted vaginally or sublingually, repeated every 3 hours as needed.

Pediatric: Not typically indicated for children.

Geriatric: Use with caution; start at lower doses due to increased risk of side effects.

Renal Impairment: Adjust dosing based on clinical response; no specific guidelines, but use cautiously.

Hepatic Impairment: Use with caution; no specific guidelines.

Pharmacokinetics

Absorption: Rapidly absorbed; peak plasma levels in 30 minutes.

Distribution: Widely distributed in tissues.

Metabolism: Metabolized in the liver.

Excretion: Primarily renal excretion.

Half Life: 20-40 minutes.

Contraindications

Pregnancy (except for indicated obstetric uses) due to abortifacient effect
Known hypersensitivity to prostaglandins

Precautions

Use cautiously in patients with cardiovascular disease, renal impairment, or asthma. Not recommended for use in women attempting pregnancy unless clearly indicated. Monitor uterine activity when used for labor induction, to prevent hyperstimulation.

Adverse Reactions - Common

Diarrhea (Common)
Abdominal pain (Common)
Nausea (Common)
Vomiting (Common)

Adverse Reactions - Serious

Uterine rupture (in pregnancy, especially with multiple gestations or previous uterine surgery) (Serious but rare)
Severe diarrhea leading to dehydration (Serious but rare)
Gastrointestinal bleeding (Rare)

Drug-Drug Interactions

Other uterotonics or medications affecting uterine activity (e.g., oxytocin)
NSAIDs may increase gastrointestinal risk

Drug-Food Interactions

Alcohol may exacerbate gastrointestinal side effects.

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Assess pregnancy status before administration. Monitor uterine activity and fetal well-being when used for obstetric purposes.

Diagnoses:

Risk for uterine hyperstimulation or rupture
Risk of diarrhea or dehydration

Implementation: Administer as prescribed; ensure patient understands the purpose and potential side effects. For obstetric uses, usually administered in a controlled setting.

Evaluation: Monitor for expected outcomes (e.g., uterine contractions, cervical ripening) and adverse effects.

Patient/Family Teaching

Warn about potential gastrointestinal side effects such as diarrhea and abdominal pain.
Explain the purpose of medication in pregnancy or GI protection.
Advise against use in pregnancy unless prescribed for obstetric indications.
Instruct on reporting any strong contractions, abdominal pain, or signs of uterine rupture.

Special Considerations

Black Box Warnings:

Uterine rupture in pregnant women when used for labor induction or pregnancy termination.

Genetic Factors: Limited data, but caution advised in women with previous uterine surgery.

Lab Test Interference: None known.

Overdose Management

Signs/Symptoms: Severe diarrhea, dehydration, uterine hyperstimulation or rupture.

Treatment: Supportive care: intravenous fluids for dehydration, uterine monitoring, and treatment of complications. Discontinue medication immediately.

Storage and Handling

Storage: Store at room temperature, 20°C to 25°C (68°F to 77°F). Keep away from moisture and light.

Stability: Stable under recommended storage conditions.