This is a drug with post-synaptic alpha-blocking and vasodilator properties.

Indications: hypertension, congestive heart failure, Raynaud's syndrome; benign prostatic hyperplasia. Cautions: first dose may cause collapse due to hypotension; reduce initial dose in renal failure. Avoid abrupt withdrawal in heart failure.

Contra-indications: congestive heart failure due to mechanical block (e.g. aortic stenosis)

Side Effects: postural hypotension, drowsiness, weakness, dizziness, headache, lack of energy; nausea, palpitation, urinary frequency; incontinence & priapism reported.

Dose: hypertension, 500 mcg 2-3 times daily, the initial dose being taken on retiring to bed at night; increased to 1 mg 2-3 times daily for a further 3- 7 days; further increased to a max. of 20 mg daily in divided doses.

Congestive heart failure, 500 mcg 2-4 times daily, initially then 1 mg 3-4 times daily; maintenance 4-20 mg daily in divided doses (rarely used).

Raynaud's syndrome, initially 500 mcg twice daily Maintenance 1-2 mg twice daily.

Benign prostatic hypertrophy, initially 500 mcg twice daily for 3-7 days (initial dose at bedtime, as for above), dose subsequently adjusted according to response; usual maintenance (and max.) 2 mg twice daily.