MISOPROSTOL

MISOPROSTOL (my-so-prost'ole) Cytotec Classifications: prostaglandin; Therapeutic:prostaglandin Pregnancy Category: X

Availability

100 mcg, 200 mcg tablets

Action

Synthetic prostaglandin E₁ analog, with both antisecretory (inhibiting gastric acid secretion) and mucosal protective properties. Increases bicarbonate and mucosal protective properties. Inhibits basal and nocturnal gastric acid secretion and acid secretion in response to a variety of stimuli, including meals, histamine, pentagastrin, and coffee. Produces uterine contractions that may endanger pregnancy and cause a miscarriage.

Therapeutic Effect

Inhibits basal and nocturanal gastric acid secretion.

Uses

Prevention of NSAID (including aspirin-induced) gastric ulcers in patients at high risk of complications from a gastric ulcer (e.g., the older adult and patients with a concomitant debilitating disease or a history of ulcers). Drug is taken for the duration of NSAID therapy and does not interfere with the efficacy of the NSAID.

Unlabeled Uses

Short-term treatment of duodenal ulcers; cervical ripening and induction of labor.

Contraindications

History of allergies to prostaglandins; Topical Use: abnormal fetal position, caesarean section, ectopic pregnancy; fetal disease, incomplete abortion multiparity, placenta previa, vaginal bleeding; pregnancy (category X), lactation.

Cautious Use

Renal impairment; inflammatory bowel disease. Safety in children <18 y is not established.

Route & Dosage

Prevention of NSAID-Induced Ulcers Adult: PO 100–200 mcg q.i.d. p.c. and h.s. or 200 mcg b.i.d. or t.i.d.

Administration

Oral

• Give with food to minimize GI adverse effects (manufacturer recommendation).
• Store away from heat, light, and moisture.

Adverse Effects (≥1%)

CNS: Headache. GI: Diarrhea, abdominal pain, nausea, flatulence, dyspepsia, vomiting, constipation. Urogenital: Spotting, cramps, dysmenorrhea, uterine contractions.

Interactions

Drug: magnesium-containing antacids may increase diarrhea.

Pharmacokinetics

Absorption: Readily from GI tract; extensive first pass metabolism. Onset: 30 min. Peak: 60–90 min. Duration: At least 3 h. Metabolism: In liver. Elimination: Primarily in urine; small amount in feces. Half-Life: 20–40 min.

Nursing Implications

Assessment & Drug Effects

• Monitor for diarrhea; may be minimized by giving drug after meals and at bedtime. Diarrhea is a common adverse effect that is dose related and usually self-limiting (often resolving in 8 d).

Patient & Family Education

• Avoid using concurrent magnesium-containing antacids because of increased incidence of diarrhea.
• Report postmenopausal bleeding to physician; it may be drug related.
• Avoid pregnancy during misoprostol therapy; use an effective contraception method while taking drug.
• Drug has abortifacient property. Contact physician and immediately discontinue drug if you become pregnant.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug