ProAmatine

Action

Forms active metabolite, desglymidodrine, an alpha₁-adrenergic agonist that activates alpha-adrenergic receptors in arteriolar and venous vasculature. This effect increases vascular resistance and ultimately raises blood pressure.

Availability

Tablets: 2.5 mg, 5 mg

Indications and dosages

➣ Symptomatic orthostatic hypotension

Adults: 10 mg P.O. t.i.d. during daytime hours with patient in upright position. Give first dose when patient arises in morning, second dose at midday, and third dose in late afternoon.

Dosage adjustment

• Renal impairment

Contraindications

• Severe coronary artery disease or organic heart disease

• Acute renal disease, urinary retention

• Pheochromocytoma

• Thyrotoxicosis

• Persistent, excessive supine hypertension

Precautions

Use cautiously in:

• renal or hepatic impairment, diabetes mellitus, vision problems

• pregnant or breastfeeding patients.

Administration

• Don't give within 4 hours of bedtime.

Adverse reactions

CNS: paresthesia

CV: vasodilation, bradycardia, supine hypertension

GI: abdominal pain, dry mouth

GU: urinary retention, frequency, or urgency

Skin: rash, pruritus, piloerection

Other: chills, increased pain

Interactions

Drug-drug. Alpha- and beta-adrenergic blockers, cardiac glycosides, steroids: increased risk of bradycardia, atrioventricular block

Alpha-adrenergic blockers, fludrocortisone: increased risk of supine hypertension

Patient monitoring

• Monitor supine and sitting blood pressures closely. Report marked rise in supine blood pressure.

• Stay alert for paresthesias.

• Monitor kidney function studies and fluid intake and output. Watch for urinary frequency, urgency, or retention.

Patient teaching

☞ Instruct patient to take while in upright position.

• Tell patient to take first dose as soon as he arises for the day, second dose at midday, and third dose in late afternoon (before 6 P.M.). Stress that doses must be taken at least 3 hours apart. Advise patient not to take drug after dinner or within 4 hours of bedtime.

☞ Instruct patient to promptly report symptoms of supine hypertension (pounding in ears, blurred vision, headache).

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, vision, and alertness.

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