Minipress

Min·i·press (mn-prs)

A trademark for the drug prazosin.

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Minipress,

a trademark for an antihypertensive (prazosin hydrochloride); an alpha₁ receptor blocking agent.

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Minipress [min´ĭ-pres]

trademark for a preparation of prazosin hydrochloride, an antihypertensive agent.

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prazosin hydrochloride

Hypovase (UK), Minipress

Pharmacologic class: Alpha₁-adrenergic blocker (peripherally acting)

Therapeutic class: Antihypertensive

Pregnancy risk category C

Action

Induces peripheral vasodilation by blocking postsynaptic alpha₁-adrenergic receptors, thereby lowering blood pressure. Decreases smooth muscle contractions of prostatic capsule and relaxes smooth muscles in bladder neck and prostate.

Availability

Capsules: 1 mg, 2 mg, 5 mg

⊘Indications and dosages

➣ Hypertension

Adults: Initially, 1 mg P.O. two or three times daily for 3 days, with first dose at bedtime; increase gradually to a maintenance dosage of 6 to 15 mg/day given in two or three divided doses.

Off-label uses

• Benign prostatic hypertrophy

Contraindications

• Hypersensitivity to drug or other quinazoline alpha₁-adrenergic blockers

Precautions

Use cautiously in:
• renal insufficiency, angina pectoris, hepatic impairment
• patients receiving diuretics concurrently
• pregnant or breastfeeding patients
• children (safety not established).

Administration

• Give test dose of 1 mg at bedtime to prevent first-dose syncope.
• Don't stop therapy suddenly. Dosage must be tapered.

Adverse reactions

CNS: dizziness, headache, asthenia, drowsiness, depression, syncope

CV: first-dose orthostatic hypotension, palpitations, angina

EENT: blurred vision, nasal congestion, epistaxis

GI: nausea, vomiting, diarrhea, abdominal cramps, dry mouth

GU: erectile dysfunction, priapism

Musculoskeletal: joint and bone pain, myalgia

Other: edema

Interactions

Drug-drug. Antihypertensives, nitrates: additive hypotension

Nonsteroidal anti-inflammatory drugs: decreased antihypertensive effect

Drug-diagnostic tests. Pheochromocytoma screening test: false-positive result

Sodium, urinary vanillylmandelic acid: increased levels

Drug-herbs. Ephedra (ma huang): acute hypertension

Patient monitoring

• After first dose, observe closely for hypotension and syncope.
• Monitor blood pressure and pulse. Watch for orthostatic hypotension.

Patient teaching

• Caution patient not to stop therapy suddenly. Dosage must be tapered.
• Tell patient drug may cause headache, muscle aches, or bone pain. Encourage him to discuss activity recommendations and pain management with prescriber.
• Inform patient that drug may cause sexual dysfunction. Advise him to discuss this issue with prescriber.
• Instruct patient to move slowly when sitting up or standing, to avoid dizziness from sudden blood pressure decrease.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, tests, and herbs mentioned above.

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Minipress®

Prazosin, see there