Alphapress 2 mg

Description

Indications

Hypertension: Alphapress is used for managing all grades of essential (primary) hypertension as well as secondary hypertension of various origins. It can be prescribed as a monotherapy or in combination with diuretics and/or other antihypertensive medications for optimal patient response. Long-term oral use does not impair renal blood flow or glomerular filtration rate, making it a safe option for hypertensive patients with renal impairment.

Left Ventricular Failure: Alphapress is indicated for the treatment of left ventricular failure. It may be added to the treatment regimen in patients who do not respond adequately or have become resistant to conventional therapy, including diuretics with or without cardiac glycosides.

Raynaud’s Phenomenon and Raynaud’s Disease: Alphapress is used to manage Raynaud’s phenomenon and Raynaud’s disease by reducing the severity, frequency, and duration of symptoms.

Benign Prostatic Hyperplasia (BPH): Alphapress serves as an adjunct therapy for relieving urinary obstruction symptoms associated with benign prostatic hyperplasia. It is also beneficial for patients awaiting prostatic surgery.

Take this medication only as prescribed by a registered physician.

Pharmacology

Prazosin works by selectively inhibiting postsynaptic alpha-1-adrenoreceptors in vascular smooth muscle, leading to decreased total peripheral vascular resistance. In hypertensive patients, it effectively lowers blood pressure in both supine and standing positions, with a more pronounced effect on diastolic pressure. There is no rebound hypertension upon sudden discontinuation.

In congestive heart failure, Prazosin reduces left ventricular filling pressure, lowers cardiac impedance, and enhances cardiac output without causing reflex tachycardia. It also improves symptoms in Raynaud’s disease by reducing vascular resistance. Additionally, Prazosin has shown benefits in BPH patients by improving urinary pressure and relieving symptoms through alpha-1-receptor antagonism in prostatic and urethral smooth muscles. Clinical studies indicate that Prazosin does not negatively impact the serum lipid profile.

Dosage & Administration

Prazosin Tablet: Treatment should begin with a low starting dose for better tolerance. Dosage is adjusted individually based on the patient’s response, typically within 1-14 days.

Hypertension: Therapy should start at 0.5 mg at bedtime, then increase to 0.5 mg twice or three times daily for 3-7 days. Dosage is gradually increased, with a maximum daily dose of 20 mg in divided doses. Patients on diuretics or other antihypertensives may require dose adjustments.

Left Ventricular Failure: Initial dosing is 0.5 mg two to four times daily, adjusted based on patient response. Clinical studies have used doses ranging from 4 mg to 20 mg daily.

Raynaud’s Phenomenon & Raynaud’s Disease: Initial dose is 0.5 mg twice daily for 3-7 days, adjusted as necessary. Maintenance dose ranges from 1 mg to 2 mg twice daily, with some cases requiring up to 2 mg three times daily.

Benign Prostatic Hyperplasia: The starting dose is 0.5 mg twice daily for 3-7 days, with an adjustment based on patient response. The usual maintenance dose is 2 mg twice daily, with a maximum daily dose of 4 mg.

Prazosin XR Tablet: Extended-release tablets should be swallowed whole. Treatment for hypertension starts at 2.5 mg once daily, with gradual increases over 7-14 days. Maintenance dose may reach 20 mg daily. Patients switching from regular Prazosin tablets should adjust to the nearest equivalent extended-release dose.

Take this medication only as prescribed by a registered physician.

Drug Interactions

Alphapress XR has been used without adverse drug interactions with the following medications:

• Cardiac glycosides: Digitalis, digoxin
• Hypoglycemic agents: Insulin, chlorpropamide, phenformin, tolazamide, tolbutamide
• Tranquilizers & sedatives: Chlordiazepoxide, diazepam, phenobarbital
• Antiarrhythmic agents: Procainamide, propranolol, quinidine
• Analgesics & anti-inflammatory drugs: Propoxyphene, aspirin, indomethacin, phenylbutazone

Contraindications

Prazosin is contraindicated in patients with known hypersensitivity to quinazolines.

Side Effects

Common side effects include dizziness, headache, drowsiness, fatigue, palpitations, and nausea. Other possible reactions include vomiting, diarrhea, constipation, abdominal pain, liver function abnormalities, edema, orthostatic hypotension, dyspnea, tachycardia, hallucinations, rash, alopecia, urinary frequency, impotence, priapism, blurred vision, tinnitus, and nasal congestion. In rare cases, worsening of pre-existing narcolepsy has been reported. Side effects generally diminish with continued use or dose adjustments.

Pregnancy & Lactation

Animal studies have not shown teratogenic effects, but safety in human pregnancy has not been fully established. Limited studies in pregnant women with severe hypertension have not reported adverse fetal effects. Prazosin is excreted in small amounts in breast milk; caution is advised when administering to nursing mothers.

Precautions & Warnings

• Hypertension: A small percentage of patients may experience significant postural hypotension, especially at the start of treatment. This can be avoided by initiating therapy at a low dose and gradually increasing it.
• Left Ventricular Failure: In patients with severe left ventricular failure, careful dose titration is necessary to prevent excessive drops in blood pressure.
• Raynaud’s Disease: Blood pressure should be monitored closely, particularly in patients taking other hypotensive medications.
• Benign Prostatic Hyperplasia: As this condition primarily affects elderly patients, careful blood pressure monitoring is required when adjusting doses.

Use in Special Populations

• Children: Safety in children under 12 years has not been established.
• Left Ventricular Failure with Mechanical Obstruction: Prazosin is not recommended for patients with conditions such as aortic or mitral valve stenosis, pulmonary embolism, or restrictive pericardial disease.

Overdose Effects

Overdose may result in profound drowsiness and depressed reflexes. If hypotension occurs, cardiovascular support is crucial. Treatment includes placing the patient in a supine position, using volume expanders, and administering vasopressors if necessary. Renal function should be monitored. Prazosin is not dialyzable due to its protein-binding properties.

Therapeutic Class

Alpha-adrenoceptor blocking drugs.

Storage Conditions

Store below 30°C, protected from light and moisture. Keep out of reach of children.