Alphapress XR

Prazosin Tablet

Tolerance is best when treatment starts with a low dose. During the first week, adjust the Prazosin dosage to how well the patient tolerates it. After that, adjust the daily dosage according to the patient's response. If a response is going to occur at a particular dose, it is usually seen within one to 14 days. Once a response appears, continue at that dosage until the response has reached its optimum, and only then add the next increment.

Hypertension

For maximum benefit, keep making small increases until the desired effect is reached or the total daily dosage reaches 20 mg. A diuretic or adrenergic beta-blocking agent may be added to improve the effect. The maintenance dosage of Prazosin may be given twice or three times daily.

Patients Receiving No Antihypertensive Therapy

Start with 0.5 mg in the evening at bedtime, then 0.5 mg b.i.d. or t.i.d. for three to seven days. Unless poor tolerance suggests the patient is unusually sensitive, increase this to 1 mg b.i.d. or t.i.d. for a further three to seven days. After that, raise the dosage gradually, guided by how the patient's blood pressure responds, up to a total daily dosage of 20 mg given in divided doses.

Patients Receiving Diuretic Therapy With Inadequate Control of Blood Pressure

Reduce the diuretic to the maintenance dosage level for that particular agent. Then start Prazosin at 0.5 mg h.s. and go on to 0.5 mg b.i.d or t.i.d. After the initial period of observation, increase the Prazosin dosage gradually, as the patient's response decides.

Patients Receiving Other Antihypertensives But With Inadequate Control

Some additive effect is expected, so reduce the dosage level of the other agent (e.g. beta-adrenergic blocking agents, methyldopa, reserpine, lsnidine etc.) and start Prazosin at 0.5 mg h.s., then 0.5 mg b.i.d. or t.i.d. Later dosage increases depend on the patient's response. Adding Prazosin to beta-adrenergic blocking agents, calcium antagonists or ACE inhibitors may bring about a substantial reduction in blood pressure. For that reason, a low initial dosage regimen is strongly recommended.

Patients With Moderate to Severe Grades of Renal Impairment

Evidence to date shows that Prazosin does not further compromise renal function in patients with renal impairment. Some patients in this group have responded to small doses of Prazosin, so start at 0.5 mg daily and make dosage increases cautiously.

Left Ventricular Failure

The recommended starting dose is 0.5 mg two, three or four times a day. Titrate the dosage to the patient's clinical response, based on careful monitoring of cardiopulmonary signs and symptoms and, when indicated, hemodynamic studies. For patients under close medical supervision, titration steps may be done as often as every two or three days. Severely ill, decompensated patients may need rapid titration over one to two days, and this is best done when hemodynamic monitoring is available. Clinical studies used therapeutic dosages from 4 mg to 20 mg daily in divided doses. Some patients may need the dosage adjusted during Prazosin therapy to keep the best clinical improvement.

Suggested Starting Dosage: 0.5 mg b.i.d., t.i.d. or q.i.d. increasing to 4 mg in divided doses.

Usual Daily Maintenance Dosage: 4 mg once daily to 20 mg in divided doses.

Raynaud's Phenomenon And Raynaud's Disease

The recommended starting dosage is 0.5 mg b.i.d. for three to seven days. Adjust the dosage according to the patient's clinical response.

Suggested Starting Dosage: 0.5 mg b.i.d.

Usual Daily Maintenance Dosage: 1 mg or 2 mg b.i.d. Some patients may need doses up to 2 mg t.i.d.

Benign Prostatic Hyperplasia

The recommended starting dose is 0.5 mg twice daily for 3 to 7 days, and it should then be adjusted to the patient's clinical response. The usual maintenance dose is 2 mg twice daily. The safety and efficacy of a total daily dosage greater than 4 mg have not been established, so use total daily dosages above 4 mg with caution.

Prazosin XR Tablet

Prazosin XR Extended-Release Tablets must be swallowed whole. Don't bite or divide them. For hypertension, Prazosin XR must be started at 2.5 mg once daily, and the 5 mg dosage form is not for initial dosing. The dosage may be increased slowly, generally over a 7 to 14-day period, depending on the response to each dose level. Doses above 20 mg once daily have not been studied.

Maintenance Dose

The dosage may be increased as clinically indicated to 20 mg given once daily. Hypertensive patients controlled on Prazosin Tablets alone, or together with other antihypertensive medicines, may be switched to Prazosin XR Extended Release Tablets at the equivalent or nearest higher total daily dose, e.g. Prazosin Tablets 4 mg daily is equivalent to Prazosin XR Extended Release Tablets 5 mg once daily. Take blood pressure measurements at the end of the dosing interval, to confirm that blood pressure control is maintained throughout the 24-hour period. Some patients may need further titration. Adding a diuretic or another antihypertensive agent to prazosin has been shown to cause an additive hypotensive effect.