Generic

Tamsulosin Hydrochloride

Indications

Tamsulosin Hydrochloride is a medication used to treat the symptoms of benign prostatic hyperplasia (BPH).

Pharmacology

Tamsulosin is a selective α1 adrenergic receptor blocker, showing its selectivity for the α1A adrenergic receptor in the human prostate. Blocking these adrenergic receptors relaxes the smooth muscles of the bladder neck and prostate, thereby improving urine flow and reducing symptoms of BPH. After oral administration in a fasting state, the absorption of 0.4mg tamsulosin hydrochloride capsules is almost complete (90%). The time to maximum concentration (Tmax) is reached between 4 and 5 hours fasting and between 6 and 7 hours when taken with food. Tamsulosin hydrochloride is highly bound to human plasma proteins (94% to 99%). Tamsulosin hydrochloride is extensively metabolized by the cytochrome P 450 enzyme in the liver, and less than 10% of the dose is excreted in the urine in its original form. The elimination half-life of tamsulosin hydrochloride in plasma is 5 to 7 hours after intravenous or oral immediate release of the preparation. Because Prostam capsules can control the pharmacokinetics of the absorption rate, the apparent half-life of tamsulosin hydrochloride is about 9 to 13 hours in healthy volunteers and 14 to 15 hours in the target population.

Dosage & Administration

Tamsulosin Hydrochloride 0.4 mg (one capsule) daily, to be taken after meal at night. The dose may be increased after 2 to 4 weeks, if necessary, to Tamsulosin Hydrochloride 0.8 mg (two capsules) once daily. If Tamsulosin Hydrochloride administration is discontinued or interrupted for several days at either the 0.4 mg or 0.8 mg dose, therapy should be started again with the Tamsulosin Hydrochloride 0.4 mg (one capsule) once daily dose. The capsule should be swallowed whole with a glass of water (about 150 ml) in the standing or sitting position. The capsule should not be crunched or chewed, as this will interfere with the modified release of the active ingredient.

Interaction

The simultaneous use of other alpha1 adrenergic receptor antagonists may produce hypotensive effects. When tamsulosin was co-administered with atenolol, enalapril, or nifedipine, no interaction was observed. Concomitant cimetidine leads to an increase in the plasma level of tamsulosin and a decrease in furosemide, but since the level remains within the normal range, it is not necessary to change the dosimetry. In the in vitro study of hepatic microsomal components (representing the drug metabolizing enzyme system related to cytochrome P450), no interaction was observed at the level of hepatic metabolism, including amitriptyline, salbutamol, glibenclamide and finasteride. However, diclofenac and warfarin can increase the elimination rate of tamsulosin.

Contraindications

Patients with hypersensitivity to tamsulosin hydrochloride, a history of orthostatic hypotension, or severe hepatic insufficiency should not use it.

As with other alpha1 blockers, a decrease in blood pressure can occur in rare situations during therapy with Tamsulosin, leading to syncope. If the patient experiences the first indications of orthostatic hypotension (dizziness, weakness), he or she should sit or lay down until the symptoms resolve. They should also be warned to avoid circumstances that might end in harm (like driving, operating machinery or performing hazardous tasks).

Before starting Tamsulosin medication, the patient should be thoroughly evaluated to rule out the presence of other diseases that might produce similar symptoms to Benign Prostatic Hyperplasia. Before starting therapy and at regular intervals afterward, a digital rectal examination and the required test of Prostate Specific Antigen (PSA) should be done.

Side Effect

Rarely, transient postural symptoms have occurred during orthostatic provocation testing after the first dose. Use in patients with micturition syncope is not advised.

Effects on ability to drive and use machines: No data is available on whether Tamsulosin adversely affects the ability to drive or operate machines. However, in this respect, patients should be aware of the fact that dizziness can occur.

Pregnancy & Lactation

Tamsulosin should not be used during pregnancy or breastfeeding.

Precautions & Warnings

During orthostatic provocation testing following the initial dosage, temporary postural symptoms have occurred on rare occasions. It is not recommended for use in people who have micturition syncope.

Effects on ability to drive and operate equipment: There is no evidence that Tamsulosin impairs one’s ability to drive or operate machines. Patients should be warned, however, that dizziness can arise in this situation.

Therapeutic Class

BPH/ Urinary retention/ Urinary incontinence

Storage Conditions

Store in a cool and dry place, below 30°C, protected from light.

Pharmaceutical Name

Drug International Ltd.