Alpha 1 Adrenergic Blockers

Question 1

What is the class for the drugs doxazosin and terazosin?

Answer 1

Alpha 1 adrenergic blockers

Question 2

Brand name for Doxazosin?

Answer 2

Cardura

Cardura XL

Question 3

Brand name for Terazosin?

Answer 3

Hytrin

Question 4

Dosage form for Terazosin?

Answer 4

Oral capsules: 1,2,5,10

Question 5

Dosage of Doxazosin?

Answer 5

Oral tablet 1,2,4,8

Oral tablet, ER 24h 4mg and 8mg

Question 6

Indication for Doxazosin and Terazosin

Answer 6

Benign Prostatic hyperplasia and HTN

Question 7

Doxazosin MOA?

Answer 7

Doxazosin selectively blocks postsynaptic α1-adrenergic receptors, reducing peripheral resistance through arterial and venous dilations. Reflex tachycardia that occurs with other vasodilators is infrequent because there is no presynaptic α2-receptor blockade. Increase urine flow by relaxing smooth muscle tone in the bladder neck and prostate.

Question 8

Terazosin MOA?

Answer 8

Terazosin selectively blocks postsynaptic α1-adrenergic receptors. Total peripheral resistance is reduced through arterial and venous dilations. Reflex tachycardia that occurs with other vasodilators is infrequent because there is no presynaptic α2-receptor blockade. Increases urine flow in BPH by relaxing smooth muscle tone in the bladder neck and prostate.

Question 9

Contraindications for doxazosin and terazosin?

Answer 9

Doxazosin: hypersensitivity to doxazosin or other quniazolines

Terazosin: hypersensitivity to terazosin

Question 10

Doxazosin ADR:

Answer 10

Common: dizziness, fatigue and malaise

Less Common: Asthenia (lack of energy/physical weakness), edema, headache, hypotension, nausea, somnolence, vertigo

Serious: hepatotoxicity, priapism ( long-lasting painful erection)

Question 11

Terazosin ADR?

Answer 11

Common: Asthenia, dizziness

Less Common: Dyspnea, headache, impotence, nausea, nasal congestion, orthostatic hypotension, peripheral edema, priapism, somnolence, syncope

Question 12

Terazosin Monitoring Parameters:

Answer 12

Efficacy: Decreased BP and improvement in obstructive urinary symptoms

Toxicity Monitoring: Signs/symptoms of hypotension, increased HR, LFTs

Question 13

Doxazosin Monitoring

Answer 13

Efficacy Monitoring: Decreased BP, improvement in urinary symptoms.

Toxicity Monitoring: Signs of hypotension and increased HR (reflex) tachycardia

Question 14

Doxazosin — key counseling points

Answer 14

Initial dose should be taken with breakfast, particularly with sustained-release products. Avoid activities requiring coordination until drug effects are realized, as drug may cause vertigo or dizziness. Rise slowly from a sitting/lying position, as this drug may cause orthostatic hypotension. Syncope or loss of consciousness is possible with first dose or dose increases, especially if patient is in an upright position. Report priapism to HCP immediately

*safety and effectiveness not established in children