Midodrine hydrochloride
Midodrine hydrochloride (ProAmatine)
Midodrine hydrochloride
(MIH-doh-dreen)
Pregnancy Category: C Amatine ProAmatine (Rx)

Classification: Treat orthostatic hypotension

Action/Kinetics: Midodrine, a prodrug, is converted to an active metabolite--desglymidodrine--that is an alpha-1 agonist. Desglymidodrine produces an increase in vascular tone and elevation of BP by activating alpha-adrenergic receptors of the arteriolar and venous vasculature. No effect on cardiac beta-adrenergic receptors. The active metabolite does not cross the blood-brain barrier; thus, there are no CNS effects. Standing systolic BP is increased by approximately 15-30 mm Hg at 1 hr after a 10-mg dose; duration: 2-3 hr. Rapidly absorbed from the GI tract. Peak plasma levels, midodrine: 30 min; t1/2: 25 min. Peak plasma levels, desglymidodrine: 1-2hr; t1/2: 3-4 hr. The bioavailability of the active metabolite is not affected by food. Desglymidodrine is eliminated in the urine.

Uses: Orthostatic hypotension in those whose lives are significantly impaired despite standard clinical care. Investigational: Management of urinary incontinence.

Contraindications: Use in severe organic heart disease, acute renal disease, urinary retention, pheochromocytoma, thyrotoxicosis, persistent and excessive supine hypertension.

Special Concerns: Use with caution in impaired renal or hepatic function, during lactation, in orthostatic hypotensive clients who are also diabetic, or in those with a history of visual problems or who are also taking fludrocortisone acetate. Safety and efficacy have not been determined in children.

Side Effects: CNS: Paresthesia, pain, headache, feeling of pressure or fullness in the head, confusion, abnormal thinking, nervousness, anxiety. Rarely, dizziness, insomnia, somnolence. GI: Dry mouth. Rarely, canker sore, nausea, GI distress, flatulence. Dermatologic: Piloerection, pruritus, rash, vasodilation, flushed face. Rarely, erythema multiforme, dry skin. Miscellaneous: Dysuria, supine hypertension. Rarely, visual field defect, skin hyperesthesia, impaired urination, asthenia, backache, pyrosis, leg cramps.

Overdose Management: Symptoms: Hypertension, piloerection, sensation of coldness, urinary retention. Treatment: Emesis and administration of an alpha-adrenergic blocking agent (e.g., phentolamine).

Drug Interactions: Alpha-adrenergic agonists / Pressor effects of midodrine Alpha-adrenergic antagonists / Antagonism of the effects of midodrine Beta-adrenergic blockers / Risk of bradycardia, AV block, or arrhythmias Cardiac glycosides / Risk of bradycardia, AV block, or arrhythmias Fludrocortisone / Intraocular pressure and glaucoma Psychopharmacologic drugs / Risk of bradycardia, AV block, or arrhythmias

How Supplied: Tablet: 2.5 mg, 5 mg

Dosage
•Tablets Orthostatic hypotension.
10 mg t.i.d. given during the daytime hours when the client is upright and pursuing daily activities (e.g., shortly before or upon arising in the morning, midday, and late afternoon-not later than 6:00 p.m.). To control symptoms, dosing may be q 3 hr. Initial dose in impaired renal function: 2.5 mg t.i.d.
Urinary incontinence.
2.5-5 mg b.i.d.-t.i.d.