Terazon5 mg

Terazon is a selective alpha-1 adrenergic receptor antagonist approved for two main indications:

• Benign prostatic hyperplasia (BPH): Established, FDA-approved use for the treatment of signs and symptoms of BPH, including urinary hesitancy, weak stream, incomplete emptying, and nocturia. Terazon relaxes smooth muscle in the bladder neck and prostate, improving urine flow. It provides symptomatic relief only and does not reduce prostate size or halt disease progression.
• Hypertension: Established, FDA-approved use for the treatment of essential hypertension, either as monotherapy or in combination with other antihypertensive agents (e.g., diuretics, beta-blockers).

Terazon is not indicated for use in women or children, and it does not treat prostate cancer.

Each dosage unit contains Terazosin Hydrochloride (as terazosin hydrochloride dihydrate) equivalent to terazosin base, available as capsules or tablets in strengths such as 1 mg, 2 mg, 5 mg, and 10 mg.

Terazon is a quinazoline-derivative, selective alpha-1 adrenoceptor blocking agent. It is chemically distinct from non-selective alpha blockers and works by selectively blocking postsynaptic alpha-1 adrenergic receptors located in vascular smooth muscle and the smooth muscle of the bladder neck and prostate. By blocking these receptors, Terazon causes relaxation of smooth muscle, leading to reduced peripheral vascular resistance (lowering blood pressure) and reduced resistance to urine outflow in men with BPH.

Terazosin Hydrochloride selectively and competitively blocks postsynaptic alpha-1 adrenergic receptors. This blockade inhibits catecholamine-induced vasoconstriction, resulting in vasodilation of both arterioles and veins and a consequent reduction in blood pressure. In the lower urinary tract, alpha-1 receptors are abundant in the smooth muscle of the prostate capsule, bladder neck, and prostatic urethra; blocking these receptors relaxes this smooth muscle, decreasing urethral resistance and improving urine flow in men with BPH, without affecting bladder contractility.

Pharmacokinetics: Terazosin Hydrochloride is well absorbed orally (bioavailability approximately 90%), with peak plasma concentrations reached in about 1 hour. It is highly protein bound (90-94%) and undergoes extensive hepatic metabolism, with a plasma elimination half-life of approximately 9-12 hours, supporting once-daily dosing. Metabolites are excreted primarily in feces via bile, with a smaller portion eliminated renally.

Take Terazon orally, preferably at bedtime with the first dose and after dose increases, to reduce the risk of dizziness or fainting from a sudden drop in blood pressure. May be taken with or without food. Swallow capsules/tablets whole. Rise slowly from a sitting or lying position, especially when starting treatment or after a dose increase.

Clinically significant interactions with Terazon include:

• PDE5 inhibitors (e.g., sildenafil, tadalafil, vardenafil): Concurrent use can cause additive vasodilation and symptomatic hypotension. If co-administered, patients should be hemodynamically stable on alpha-blocker therapy first, and PDE5 inhibitor therapy should be initiated at the lowest dose with adequate time spacing from the alpha-blocker dose.
• Other antihypertensive agents (e.g., diuretics, beta-blockers, ACE inhibitors, calcium channel blockers): Additive blood-pressure-lowering effect; dose adjustment of one or both agents may be required.
• Verapamil: Can increase terazosin plasma concentrations, potentially increasing hypotensive effect.
• Other alpha-adrenergic blocking agents: Concurrent use is generally avoided due to overlapping and additive effects.

Common side effects of Terazon include:

• Dizziness
• Orthostatic (postural) hypotension
• Asthenia (weakness/fatigue)
• Somnolence (drowsiness)
• Nasal congestion
• Peripheral edema
• Headache
• Palpitations

Less common but serious effects include syncope (fainting), particularly with the first dose or after dose increases (see Precautions and Warnings), and priapism (rare, requires emergency treatment).

Terazon is not indicated for use in women. Adequate and well-controlled studies in pregnant women are lacking. Terazon should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus; consult a physician before use. It is not known whether Terazon is excreted in human breast milk; because many drugs are excreted in breast milk, caution should be exercised and a physician consulted before use during breastfeeding.

First-dose effect: Terazon can cause marked orthostatic hypotension with syncope, especially with the first dose, within 90 minutes of dosing, or following dose increases or interruption of therapy. Start therapy at bedtime with the lowest dose, titrate cautiously, and advise patients to avoid situations where injury could result from dizziness or syncope, including driving, for the first 24 hours after the initial dose or a dose increase.

Intraoperative floppy iris syndrome (IFIS): IFIS has been observed during cataract surgery in some patients treated with alpha-1 blockers, including Terazon, currently or in the past. Inform the ophthalmologist of any current or prior use of Terazon before cataract surgery.

Concurrent PDE5 inhibitor use: See Interactions for guidance on managing additive hypotensive risk.

Priapism: Rare cases of prolonged, painful erection have been reported; this is a medical emergency requiring immediate treatment.

Hepatic impairment: Use with caution, as terazosin undergoes extensive hepatic metabolism.

Overdose with Terazon may result in profound hypotension. If overdose is suspected, seek immediate medical attention or contact emergency services or a poison control center. Management may involve restoring blood pressure and heart rate through supportive measures such as keeping the patient supine, and other measures as directed by a physician; general medical supervision is required. Terazosin is highly protein bound, so dialysis is not expected to be of significant benefit.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

Elderly: No overall differences in safety or effectiveness have been observed between elderly and younger patients, but elderly patients may be more sensitive to blood-pressure-lowering effects; use with caution.

Renal impairment: No dosage adjustment is generally required, as terazosin is eliminated primarily via hepatic/biliary metabolism, but caution is advised, and patients should be monitored.

Hepatic impairment: Use with caution given the extensive hepatic metabolism of Terazon.

Pediatric: Safety and efficacy of Terazon have not been established in children.

Women: Terazon is not indicated for use in women.

Duration is individualized and typically long-term/chronic for both hypertension and BPH, as symptoms and blood pressure elevation return upon discontinuation. For BPH, an adequate therapeutic trial of at least 4-6 weeks at the target dose is recommended before assessing effectiveness. Continued use should be re-evaluated periodically by the prescribing physician.

Alpha-1 adrenergic receptor blocker (quinazoline-derivative alpha-blocker).

Category C