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Isometheptene/Dichloralphenazone/Paracetamol

    DEA Class;  Rx

    Common Brand Names; Midrin

    • Analgesics, Other Combos

    Isometheptene: Elicits sympathomimetic effect; constricts dilated cerebral/cranial arterioles

    Dichloralphenazone: Elicits mild sedative effect; reduces emotional response to painful stimulus

    Acetaminophen: Inhibitis prostaglandin sythesis in CNS and may block peripheral pain impulse generation; acts on hypothalamus to antipyresis

    For the treatment of Tension Headache, Migraine Headache

    Hypersensitivity

    Hepatitis or hepatic disease

    Glaucoma

    Severe renal impairment

    Hypertension

    Peripheral vascular disease

    Cardiovascular insufficiency, including recent MI or stroke

    Organic heart disease

    Within 14 days of taking MAO inhibitors

    Rash

    Transient dizziness

    Acetaminophen use is associated with rare, but serious skin reactions that can be fatal; these reactions include Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP); symptoms may include skin redness, blisters and rash

    May increase respiratory depressant effects; caution with head injury, COPD, or other conditions with decreased respiratory drive

    Controlled substance (dichloralphenazone); may cause tolerance/dependence

    If therapy seems to become less effective over time, it may be a sign that the patient is becoming dependent on the medication; dose should not be increased to improve relief

    If new headache occurs within 1 day after taking the medication, a headache begins to occur every day or continues for several days in a row, it may be a sign of becoming dependent on the medication; continuing therapy when this occurs may cause even more headaches over time; ask healthcare professional how to relieve the headaches

    Pregnancy

    Refer to individual monographs

    Lactation

    Refer to individual monographs

    Adults

    2 capsules PO at onset of headache, then 1 capsule PO q1hr until headache relieved up to a cumulative dose of 5 capsules/12 hr

    1-2 capsules PO q4hr; not to exceed 8 capsules/24 hr

    Pediatric

    Safety and efficacy not established

    isometheptene/dichloralphenazone/acetaminophen

    capsule: Schedule IV

    • 65mg/100mg/325mg