midodrine (Rx)

>10%

Paresthesia (18%)

Piloerection (13%)

Pruritus (13%)

Supine hypertension (7-13%)

Urinary retention or urgency (up to 13%)

1-10%

Chills (5%)

Pain, including abdominal pain (5%)

Rash (2%)

<1%

Anxiety

Canker sore

Confusion

Dizziness

Dry skin

Erythema multiforme

Facial flushing

Flushing

Headache

Hyperesthesia

Insomnia

Intracranial pressure increased

Nausea

Somnolence

Weakness

Xerostomia

Contraindications

Severe organic heart disease, supine HTN, acute renal disease, urinary retention, pheochromocytoma, thyrotoxicosis

Cautions

May slow heart rate primarily due to vagal reflex; use caution when administering concomitantly with negative chronotropes, including digoxin, beta blockers, or other agents that decrease heart rate; discontinue use if signs or symptoms of bradycardia occur

Risk of hypertension increases with concomitant administration of drugs that increase blood pressure (phenylephrine, pseudoephedrine, ephedrine, dihydroergotamine, thyroid hormones, or droxidopa); avoid concomitant use of drugs that increase blood pressure; if concomitant use cannot be avoided, monitor blood pressure closely

Avoid concomitant administration with MAO inhibitors or linezolid

It is essential to monitor supine and sitting blood pressures in patients receiving therapy; uncontrolled hypertension increases risk of cardiovascular events, particularly stroke

Avoid concomitant use with treatment agents that may cause vasoconstriction

Use caution in patients with diabetes mellitus, vision problems, and renal or hepatic impairment

Take drug no later than 6 pm and 3-4 hr before bed to minimize supine HTN

Pregnancy category: C

Lactation: Not known if excreted into breast milk; avoid

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Alpha-1 selective adrenergic agonist; increases peripheral vascular resistance; arteriolar and venous tone increases and results in a rise in sitting, standing, and supine systolic and diastolic blood pressure in patients with orthostatic hypotension

Absorption

Bioavailability: 93%

Onset: 45-90 min (initial effect); 60 min (max effect)

Duration: 2-3 hr

Peak plasma time: 1-2 hr (desglymidodrine); 30 min (midodrine)

Distribution

Protein bound: Minimal

Vd: <1.66 L/kg

Metabolism

Extensively undergoes enzymatic hydrolysis in the systemic circulation; prodrug (midodrine) converted to desglymidodrine (active agent)

Metabolites: Desglymidodrine, 15 times as potent as midodrine; primarily responsible for treatment activity (active)

Elimination

Half-life elimination: 3-4 hr (desglymidodrine); 25 min (midodrine)

Dialyzable: HD: Yes

Renal clearance: 385 mL/min

Excretion: Feces (1-2%); urine (80% [desglymidodrine])