Generic Name

Dihydroergotamine Mesylate

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Classification

FDA Approved Indications

• Acute treatment of migraine headaches with or without aura

Mechanism of Action

Dihydroergotamine acts as an agonist at serotonin 5-HT1B and 5-HT1D receptors on cranial blood vessels and sensory nerves, leading to vasoconstriction and inhibition of pro-inflammatory neuropeptide release, thus relieving migraine symptoms.

Dosage and Administration

Adult: 4 mg inhaled starting dose, repeat every 15 minutes as needed, up to 2 administrations within 24 hours; for nasal spray, typically 1 spray per nostril, may repeat after at least 15 minutes and up to 2 sprays per nostril in 24 hours.

Pediatric: Not approved for pediatric use.

Geriatric: Use with caution; start at lower end of dosage range due to increased sensitivity.

Renal Impairment: Adjust dosage; use with caution as clearance might be reduced.

Hepatic Impairment: Use with caution; hepatic impairment may increase systemic exposure.

Pharmacokinetics

Absorption: Bioavailability varies; oral bioavailability is low (~2%), nasal and injectable forms provide higher bioavailability.

Distribution: Widely dispersed, crosses the blood-brain barrier.

Metabolism: Hepatic via oxidative dealkylation.

Excretion: Primarily in feces, some in urine.

Half Life: Approximately 2 hours.

Contraindications

• Coronary artery disease or history of myocardial infarction
• Uncontrolled hypertension
• Vomiting or nausea with potential aspiration risk
• Use within 24 hours of another ergot or triptan
• Known hypersensitivity to ergot alkaloids

Precautions

• Use cautiously in elderly, hepatic or renal impairment, or ischemic heart disease; monitor blood pressure; avoid in pregnancy unless benefits outweigh risks.

Adverse Reactions - Common

• Nausea (Common)
• Vasoconstriction effects such as cold extremities, numbness (Common)
• Dizziness, vertigo (Common)

Adverse Reactions - Serious

• Ischemic stroke (Rare)
• Severe hypertension (Rare)
• Ergotism (prolonged vasoconstriction) (Rare)

Drug-Drug Interactions

• Other vasoconstrictors, including triptans and other ergot alkaloids; CYP3A4 inhibitors such as macrolides, azole antifungals, and protease inhibitors may increase levels.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Instruct patient to report chest pain, cold extremities, or unusual numbness or tingling.
• Use at the first signs of migraine for best efficacy.
• Do not use more frequently than prescribed.
• Inform about possible side effects and when to seek medical help.

Special Considerations

Black Box Warnings:

• Vasospasm leading to ischemic events; avoid in patients with coronary artery disease.
• Use with caution in pregnancy unless clearly indicated.

Genetic Factors: No specific genetic testing recommended.

Lab Test Interference: May slightly elevate serum enzyme levels or affect vascular assessments.

Overdose Management

Signs/Symptoms: Prolonged vasospasm, ischemia, cool extremities, numbness, tingling, chest pain.

Treatment: Discontinue drug; provide supportive care; administer vasodilators like nitroglycerin if indicated and under medical supervision.

Storage and Handling

Storage: Store at room temperature, away from direct light and moisture.

Stability: Stable up to the expiration date on the package.