Isopap, Duradrin, Midrin, Migratine
Classifications: sympathomimetic; analgesic, nonnarcotic;
Therapeutic: antimigraine; analgesic, non-narcotic

Pregnancy Category: C
Controlled Substance: Schedule Schedule C-IV


65 mg

isometheptene mucate, 100 mg

dichloralphenazone, 325 mg

APAP capsules


Isometheptene is a sympathomimetic amine that acts by constricting cranial and cerebral arterioles. Isometheptene relieves vascular headaches. Dichloralphenazone is a mild sedative that helps reduce headache pain. Acetaminophen is a mild analgesic.

Therapeutic Effect

Effective as a mild sedative, reduces headache pain as well as being a mild analgesic.


Relief for tension, vascular, and migraine headaches.


Patients with glaucoma; severe renal disease, organic heart disease; hepatic disease; concurrent MAO inhibitors; pregnancy (category C), lactation.

Cautious Use

Hypertension; peripheral vascular disease, and recent cardiovascular attacks; older adults; pulmonary disease.

Route & Dosage

Tension Headache
Adult: PO 1–2 capsules q4h up to 8 capsules/24 h

Migraine Headache
Adult: PO 2 capsules at onset, then 1 capsule qh until relief (max: 5 capsules/12 h)


  • Do not give this drug to anyone who is concurrently using an MAOI. Allow 14 d to elapse between discontinuation of the MAOI and administration of this drug.
  • Do not give more than 8 capsules in a 24 h period.
  • Store at 15°–30° C (59°–86° F) in a dry place.

Adverse Effects (≥1%)

CNS: Transient dizziness. GI: Acetaminophen hepatotoxicity. Skin: Rash.


Drug: maois may cause hypertensive crisis; other acetaminophen-containing drugs (including OTC) may increase risk of hepatotoxicity.


Absorption: Rapidly absorbed. Metabolism: Dichloralphenazone is metabolized to chloral hydrate and antipyrine. See ACETAMINOPHEN and CHLORAL HYDRATE for more detail. Elimination: Renal and hepatic. Half-Life: 12 h.

Nursing Implications

Assessment & Drug Effects

  • Monitor BP closely with preexisting hypertension.
  • Monitor lower extremity perfusion with a history of PVD.

Patient & Family Education

  • Avoid, or moderate, alcohol use while taking this drug.
  • Do not drive or engage in other potentially hazardous activities until response to drug is known.
  • Report any decrease in tolerance to walking if you have a history of PVD.

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

© 2006-2022 Last Updated On: 12/03/2022 (0)
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