rizatriptan benzoate

Action

Thought to act as agonist at specific 5-HT₁ receptor sites in intracranial vessels, causing vasoconstriction. Also may act on sensory trigeminal nerves, reducing transmission along pain pathways.

Availability

Tablets: 5 mg, 10 mg

Tablets (orally disintegrating): 5 mg, 10 mg

Indications and dosages

➣ Acute migraine

Adults: 5 to 10 mg P.O.; may repeat in 2 hours, not to exceed 30 mg in 24 hours. For patients receiving propranolol concurrently, 5 mg P.O., up to a maximum of three doses in 24 hours.

Children ages 6 to 17 weighing 40 kg (88 lb) or more: 10 mg P.O. as a single dose. For patients receiving propranolol concurrently, 5 mg P.O., up to a maximum of three doses in 24 hours.

Children ages 6 to 17 weighing less than 40 kg (88 lb): 5 mg P.O. as a single dose. Don't prescribe drug for propranolol-treated children who weigh less than 40 kg.

Contraindications

• Hypersensitivity to drug or its components

• Ischemic heart disease or other significant cardiovascular disease

• Ischemic bowel disease

• Transient ischemic attacks

• Basilar or hemiplegic migraine

• Uncontrolled hypertension

• Use of other 5-HT₁ agonists or ergot-type compounds (dihydroergotamine, methysergide) within 24 hours

• MAO inhibitor use within past 14 days

Precautions

Use cautiously in:

• severe renal impairment (especially in dialysis patients), moderate hepatic impairment, cardiovascular risk factors

• phenylketonuria (PKU) in patients receiving orally disintegrating tablets

• pregnant or breastfeeding patients

• children younger than age 6 (safety not established).

Administration

• Place orally disintegrating tablet on patient's tongue to dissolve. Make sure he swallows it with saliva only. Don't give with beverages.

See Don't give within 14 days of MAO inhibitors (may cause serious adverse reactions).

Adverse reactions

CNS: headache, dizziness, drowsiness, asthenia, fatigue, paresthesia, decreased mental acuity, euphoria, tremor

CV: chest pain, tightness, heaviness, or pressure; hypertensive crisis; arrhythmias, myocardial infarction (MI) (rare)

GI: nausea, vomiting, diarrhea, dry mouth

Respiratory: dyspnea

Skin: flushing

Other: neck, throat, or jaw pain, tightness, or pressure; hot flashes; warm or cold sensations; noncoronary vasospastic reactions, serotonin syndrome

Interactions

Drug-drug. Ergot or ergot-type compounds (such as dihydroergotamine, methysergide), other 5-HT₁ agonists: additive vasoactive effects

MAO inhibitors, propranolol: increased rizatriptan blood level, greater risk of adverse effects

Selective serotonin reuptake inhibitors: weakness, hyperreflexia, incoordination

Drug-herbs. S-adenosylmethionine (SAM-e), St. John's wort: increased risk of adverse serotonergic effects, including serotonin syndrome

Patient monitoring

• Monitor patient's response to drug. Assess need for repeat doses.

• Assess vital signs and cardiovascular status, especially if patient has cardiovascular risk factors. Discontinue drug if arrhythmia occurs.

See Be aware that drug may cause noncoronary vasospastic reactions, such as peripheral vascular ischemia, GI vascular ischemia and infarction (abdominal pain and bloody diarrhea), splenic infarction, and Raynaud's syndrome. In patients who experience signs or symptoms suggestive of noncoronary vasospasm reaction, rule out the suspected vasospasm reaction before giving additional doses.

See Be aware that drug may cause serotonin syndrome. Discontinue drug if serotonin syndrome is suspected.

Patient teaching

• Teach patient how to use drug. Stress that it's effective only in treating diagnosed migraine-not in preventing migraine or treating other types of headache.

• Advise patient to peel back blister pack of Maxalt-MLT with dry hands and place tablet on tongue. Tell him to swallow drug with saliva only, not beverages.

• Tell patient he may repeat dose in 2 hours if headache recurs, but should take no more than 30 mg in 24 hours.

• Inform patient with PKU that orally disintegrating tablets contain phenylalanine.

See Teach patient how to recognize and immediately report signs and symptoms of significant increases in blood pressure, arrhythmia, MI, serotonin syndrome, and vasospastic reactions.

See Instruct female patient to immediately report possible pregnancy.

• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs and herbs mentioned above.