Terazosin

Terazosin is an Antihypertensive agent belonging to Alpha Adrenergic blockers.

Terazosin is used in the treatment of Hypertension and Benign prostatic hyperplasia. It is also used to treat Ureteral stone(s) and expulsion.

It is rapidly and almost completely absorbed from the gastrointestinal tract. Delayed time to peak plasma concentration with food by approx 40 minutes, and bioavailability is approx 90%. The plasma protein binding was approx 90-94%. It is metabolized in the liver via demethylation and conjugation; undergoes minimal first-pass metabolism.It is excreted via urine (approx 40%, approx 10% as unchanged drug); faeces (approx 60%, approx 20% as unchanged drug). Elimination half-life: Approx 8-13 hours.

The onset of Action of Terazosin is within 15 minutes.

The Duration of action of Terazosin is within 24 hours.

The Tmax of Terazosin was within 1 hour and the Cmax of Terazosin was found within 26.61±7.16 ng/ml.

The common side effects are dizziness, drowsiness, headache, weakness, Nausea, strong irregular heartbeat, swelling, and dizziness upon standing.

Terazosin is available in dosage forms, such as tablets and capsules.

Terazosin is available in the USA, France, South Korea, Canada, and India.

Terazosin is an α1-adrenoceptor antagonist. It decreases blood pressure by reducing the total peripheral vascular resistance through competitive inhibition of the postsynaptic α1-adrenoceptors. Additionally, the blockade of these receptors in the bladder, neck, and prostate produces smooth muscle relaxation, thus reducing bladder outlet obstruction.

Terazosin is available in the form of a dosage forms, such as tablets and capsules.

Terazosin tablet is taken by mouth. It is usually taken once or twice a day with or without food.

Terazosin is used in the treatment of Hypertension and Benign prostatic hyperplasia. It is also used to treat Ureteral stone(s) and expulsion.

Terazosin works by relaxing the muscles in your bladder and prostate to improve urine flow. It also widens blood vessels in your body so blood can flow through more easily. This helps lower your blood pressure.

Terazosin is approved for its use in the following clinical indications:

Management of Hypertension.

Treatment of symptomatic benign prostatic hyperplasia (BPH).

Although not approved, there have been certain label use documented for Terazosin which include:

The dosage and the Duration of treatment should be as per the clinical judgment of the treating physician.

Terazosin is available in various dosage strengths: 1 mg, 2 mg, 5 mg, 10 mg.

Terazosin is available in the form of dosage forms such as tablets and capsules.

Hemodialysis: 10% dialyzable; supplemental dose not necessary.

Children and Adolescents: Limited data available: Oral: Initial: 1 mg once daily, typically administered at bedtime; slowly increase the dose to achieve desired blood pressure as tolerated; maximum daily dose: 20 mg/day.

Note: If the drug is discontinued for greater than several days, consider beginning with the initial dose and titrate as needed.

Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult the drug interactions database for more information.

Terazosin is approved for the treatment of Hypertension.

Hypertension: It has been observed that the low-salt Dietary Approach to Stop Hypertension (DASH) diet lowers blood pressure. Sometimes after a few weeks, its effects on blood pressure become noticeable.

Terazosin may be contraindicated in the following.

The only absolute contraindication to the usage of Terazosin is allergy or hypersensitivity to the medication. Relative contraindications include usage in geriatric populations due to the potential for patient harm associated with syncope and/or postural hypotension due to terazosin use, patients with heart failure, and general intolerance of the adverse effects associated with Terazosin. It is important to note that in geriatric patient populations, the occurrence of syncope or orthostatic hypotension can lead to falls, which are associated with increased mortality, morbidity, loss of functional capacity, and institutionalization for diagnostic workup/rehabilitation related to the syncope.

While Terazosin is not contraindicated for use in pediatric populations, caution is advised due to limited data available regarding the use of the drug in children. However, there are small studies of safe usage in children without adverse outcomes.

The treating physician must closely monitor the patient and keep pharmacovigilance as follows.

• CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks that require mental alertness (eg, operating machinery or driving).

• Floppy iris syndrome: Intraoperative floppy iris syndrome has been observed in cataract surgery patients who were on or were previously treated with alpha1-blockers; there appears to be no benefit in discontinuing alpha-blocker therapy prior to surgery. May require modifications to surgical technique.

• Orthostatic hypotension/syncope: May cause significant orthostatic hypotension and syncope, especially with the first dose or first few days of therapy; anticipate a similar effect if therapy is interrupted for a few days, if dosage is rapidly increased, or if another antihypertensive drug (particularly vasodilators) or a PDE-5 inhibitor is introduced.

• Priapism: Priapism has been associated with use (rarely); seek immediate medical assistance for erections lasting longer than 4 hours.

• Heart failure: In a scientific statement from the American Heart Association, Terazosin has been determined to be an agent that may exacerbate underlying myocardial dysfunction (magnitude: moderate).

• Appropriate use: BPH: Rule out prostatic carcinoma before beginning therapy (many symptoms of BPH and prostate cancer are similar).

Avoid taking alcohol with Terazosin as it may result in side effects like headache, dizziness and faintness.

Terazosin was not teratogenic in either rats or rabbits when administered at oral doses up to 280 and 60 times, respectively, the maximum recommended human dose. Fetal resorptions occurred in rats dosed with 480 mg/kg/day, approximately 280 times the maximum recommended human dose. Increased fetal resorptions, decreased fetal weight and an increased number of supernumerary ribs were observed in offspring of rabbits dosed with 60 times the maximum recommended human dose. These findings (in both species) were most likely secondary to maternal toxicity. There are no adequate and well-controlled studies in pregnant women and the safety of Terazosin in pregnancy has not been established. Terazosin HCl is not recommended during pregnancy unless the potential benefit justifies the potential risk to the mother and fetus.

Salt Substitutes: Those who are taking Terazosin should avoid sodium, calcium and magnesium-rich foods. The salts may reduce the blood-pressure lowering effect of Terazosin.

The adverse reactions related to molecule Terazosin can be categorized as

●  Common Adverse effect:

Cough ,headache, dizziness, drowsiness

●  Less Common adverse effects:

Swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower, hoarseness, difficulty breathing or swallowing, lightheadedness, fainting, rash, yellowing of the skin or eyes, fever, sore throat, chills, and other signs of infection.

The clinically relevant drug interactions of Terazosin is briefly summarized here.

Increased incidence of dizziness or other dizziness-related adverse events with ACE inhibitors (e.g., captopril) and diuretics. May increase the risk of hypotension with other antihypertensive agents (e.g. verapamil) and phosphodiesterase-5 inhibitors (e.g. sildenafil, tadalafil)

Symptom: Acute hypotension.

Management: Supportive treatment. Prioritize CV support. Keep the patient in a supine position to restore blood pressure and normalize heart rate; if inadequate, may give volume expanders to treat shock first and then administer vasopressors if necessary. Monitor renal function.

Terazosin is an α1-adrenoceptor antagonist. It decreases blood pressure by reducing the total peripheral vascular resistance through competitive inhibition of the postsynaptic α1-adrenoceptors. Additionally, the blockade of these receptors in the bladder neck and prostate produces smooth muscle relaxation, thus reducing bladder outlet obstruction. Alpha1-specific blocking agent with minimal alpha2 effects; this allows peripheral postsynaptic blockade, with the resultant decrease in arterial tone, while preserving the negative feedback loop which is mediated by the peripheral presynaptic alpha2-receptors; Terazosin relaxes the smooth muscle of the bladder neck, thus reducing bladder outlet obstruction

There are some clinical studies of the drug Terazosin mentioned below: