Midodrine Hydrochloride

A to Z Drug Facts

 Action Activates arteriolar and venous a-adrenergic receptors resulting in an increase in vascular tone and elevation of blood pressure.

 Indications Treatment of symptomatic orthostatic hypotension in patients whose lives are considerably impaired despite standard clinical care, including support stockings, fluid expansion and lifestyle changes. Unlabeled use(s): Management of urinary incontinence.

 Contraindications Severe organic heart disease, acute renal failure, urinary retention, phenochromocytoma, thyrotoxicosis or in patients with persistent and excessive supine hypertension.

 Route/Dosage

ADULTS: PO 10 mg tid during daytime hrs. Renal function impairment: Start with 2.5 mg/dose.

 Interactions

Vasoconstrictors (eg, dihydroergotamine, ephedrine, phenylephrine, phenylpropanolamine, pseudoephedrine): May enhance pressor effects of midodrine. Alpha-blocking agents (eg, prazosin, terazosin, doxazosin): May antagonize pressor effects of midodrine. Cardiac glycosides: May precipitate bradycardia, AV block or arrhythmia. Fludrocortisone: May exacerbate supine hypertension.

 Lab Test Interferences None well documented.

 Adverse Reactions

CV: Supine and sitting hypertension; bradycardia. CNS: Paresthesia; headache; confusion; nervousness; anxiety; confusion; abnormal thinking. DERM: Piloerection; scalp pruritis; rash. GI: Abdominal pain; dry mouth. GU: Dysuria (frequency, impaired micturation, urinary retention, urinary urgency). OTHER: Pain; chills; facial flushing; feeling of fullness/pressure in head.

 Precautions

Pregnancy: Category C. Lactation: Undetermined. Children: Safety and efficacy not established. Supine hypertension: Potentially most serious adverse reaction. Most common in patients with elevated pre-treatment supine systolic blood pressure (mean 170 mm/hg). Use is not recommended in patients with pre-treatment supine systolic blood pressure >180 mm/hg. Monitor supine and sitting blood pressures. Bradycardia: May occur due to vagal reflex. Use caution when coadministering with other agents that can reduce heart rate (eg, cardiac glycosides, b-blockers, psychopharmacologic agents). Urinary retention: Use with caution due to effect on a-adrenergic receptors of bladder neck. Renal function impairment: Use with caution. Initiate therapy with smaller doses. Hepatic function impairment: Use with caution. Diabetes: Use with caution.

 Administration/Storage

• May be taken without regard to meal except evening dose.
• Dosing should be q 4 hrs during daylight hours while patient is upright. Administer first dose shortly before or upon arising, second dose at midday and third dose in late afternoon (no later than 6 pm).
• Doses may be given in 3 hour intervals, if required, to control symptoms, but not more frequently.
• Do not administer after evening meal or < 4 hrs before bedtime.
• Store at room temperature.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies. Note hepatic or renal impairment.
• Obtain necessary lab tests (eg, renal, liver) before initiating therapy.
• Monitor supine, sitting and standing blood pressure and pulse frequently during initiation of therapy.
• If supine hypertension noted, have patient sleep with head of bed elevated.
• If supine blood pressure noted to be > 180 mm/hg, withhold therapy and notify physician.

 Patient/Family Education

• Ensure that patient understands dosing schedule. Caution patient not to take dose after dinner or < 4 hours before bedtime.
• Medication can be taken without regard to meal except evening dose.
• Advise patient not to change the dose, dosing schedule or discontinue the medication without consulting with their physician.
• Ensure that patient has, and can use, a home blood pressure monitoring device. Advise patient to monitor blood pressure and pulse at regular intervals and notify physician if hypertension or bradycardia noted.
• Advise patient to elevate head of bed if supine hypertension noted.
• Educate patient regarding signs and symptoms of supine hypertension eg, cardiac awareness, pounding in ears, headache, blurred vision). Advise patient to discontinue medication and notify physician if noted.
• Caution patient to consult with their physician or pharmacist before taking other drugs, including otc medications.
• Advise female patients to notify their physician if they become pregnant or intend to become pregnant or are breastfeeding while taking this drug.
• Instruct patient to report the following symptoms: numbness or tingling; goosebumps; chills; flushing; feeling of fullness/pressure in head; eadache; confusion; nervousness; urinary problems.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts