Urilax

Each extended release tablet contains: Tamsulosin (as hydrochloride) 200 mcg.

Pharmacology: Pharmacokinetics: Tamsulosin is a selective alpha-1 antagonist that acts by decreasing the smooth muscle tone in the prostate and urinary bladder neck with resultant increase in the urine flow and relief of the symptoms associated with benign prostatic hyperplasia. Although the symptoms of benign prostatic hyperplasia is mostly due to an increase in the size of the prostate gland with proliferation of smooth muscle cells in the stroma of the prostate, these urinary symptoms are partly due to an increase in smooth muscle tone in the prostate and urinary bladder neck mediated by sympathetic nervous system stimulation of alpha-1 adrenergic receptors. Tamsulosin exhibits selectivity for alpha-1 adrenergic receptors of the A subtype as opposed to the B subtype which is important in maintaining the vascular smooth muscle tone. Since about 70% of the alpha-1 adrenergic receptors found in the human prostate gland are of the subtype alpha-1A, tamsulosin as expected was demonstrated to be efficacious in relieving the symptoms associated with benign prostatic hyperplasia with little or no alteration noted in the baseline systemic blood pressure.
Urilax is formulated as an extended release tablet of the non-ionic gel matrix type. Tamsulosin administered as an extended release tablet is absorbed from the intestine with a bioavailability of approximately 55-59%. The extended release formulation allows slow and consistent release of tamsulosin which is maintained over the whole pH range encountered in the gastrointestinal tract with little fluctuation over 24 hours allowing it to be administered on a once daily dosing. The rate and extent of absorption of orally administered tamsulosin extended release tablet is not affected by oral food intake. Tamsulosin extended release tablets demonstrate linear pharmacokinetics with median time to peak plasma levels (T_max) of 6 hours after a single oral dose given in the fasted state. On day 4 of multiple daily oral dosing when steady state conditions have expectedly been achieved, T_max is 4 to 6 hours irrespective of whether the tamsulosin extended release tablet was orally administered in the fasted or fed state. The peak plasma level (C_max) is approximately 6 ng/mL with the first dose of tamsulosin extended release tablet but increases to 11 ng/mL after achievement of the steady state condition. As a result of the extended release formulation of Urilax, the trough plasma concentration of tamsulosin falls only to 40% of the peak plasma concentration under both fasted and fed states. There is however considerable inter-patient variation in plasma levels of tamsulosin both after single and multiple oral dosing. Based on a bio-equivalent study done on 40 healthy adult Korean males which compared Urilax (Uronal SR in Korea) 200 mcg tablets to Harnal-D 200 mcg tablets, there were no significant difference noted in terms of the maximum serum concentrations (C_max 90% CI log 0.9276 - log 1.0793) and area under the curve (AUC 90% CI log 0.9943 - log 1.2231). Tamsulosin is about 99% bound to plasma proteins with a small volume of distribution of about 0.2 L/kg. Tamsulosin has a low first-pass effect on account of its slow hepatic metabolism.
Most of the orally administered tamsulosin is present in the plasma in the form of unchanged drug though it is extensively metabolized by the cytochrome P450 enzymes in the liver and only about 4-6% of the oral dose is excreted unchanged in the urine. In rats, hardly any induction of microsomal liver enzymes was noted to be caused by the administration of tamsulosin. Orally administered tamsulosin is mostly recovered in the urine both as unchanged drug and as inactive metabolites with only 20% of the oral dose recovered in the feces. All of the metabolites of tamsulosin are either inactive or only slightly active compared to the original compound. The elimination half-life (T_1/2) of Urilax is about 19 hours after a single dose and 15 hours in steady state conditions after multiple oral dosing.

Tamsulosin is indicated for use in the symptomatic treatment of benign prostatic hyperplasia.

The usual dose is 200 mcg tablet given one to two tablets once daily.
Orally administered tamsulosin may be taken with or without food and should be swallowed whole without chewing or crushing the tablet to avoid affecting the extended release of the active ingredient. Dose adjustments are not necessary in patients with mild to moderate renal or hepatic insufficiency and in the elderly.

In case of an overdose with tamsulosin, blood pressure and heart rate should be closely monitored and in situations where hypotension is encountered, patients should be placed in the supine position and administration of intravenous fluids with or without vasopressors instituted when necessary. Since tamsulosin is highly protein-bound, dialysis would not likely be of any benefit.

Tamsulosin is contraindicated in patients who have exhibited a history of hypersensitivity reaction to tamsulosin or to any of its components.

Although less likely to occur compared with other selective alpha-1 blockers, reduction in blood pressure, orthostatic hypotension or even syncope may rarely occur during treatment with tamsulosin. At the first sign of orthostatic hypotension which may include dizziness or weakness, the patient should be instructed to sit or lie down until the symptoms abate. At the initiation of therapy, patients should therefore be advised to avoid situations where injury could possibly be sustained in the event that syncope would occur. Occasional cases of priapism have been observed with tamsulosin like with other selective alpha-1 blockers where patients should be advised on its proper and urgent treatment to prevent the possible consequence of permanent impotence. Other conditions which may manifest similarly as benign prostatic hyperplasia especially prostatic cancer should be excluded prior to initiation of therapy with tamsulosin. Digital rectal examination and, when necessary, determination of prostate specific antigen (PSA) should be performed before treatment and at regular intervals thereafter. The Intraoperative Floppy Iris Syndrome (IFIS), a variant of the Small Pupil Syndrome has been observed during cataract surgery in some patients currently or previously treated with tamsulosin. IFIS may lead to increased procedural complications during the operation and therefore the initiation of therapy with tamsulosin in patients in whom cataract surgery is being contemplated is not recommended. Discontinuation of tamsulosin therapy 1-2 weeks prior to cataract surgery have been considered beneficial, however concrete evidence of such benefit and the time of discontinuation of therapy prior to cataract surgery has not yet been established. As part of the pre-operative assessment, current or previous therapy with tamsulosin should be ascertained prior to cataract surgery so appropriate measures can be put in place to manage IFIS during surgery. Caution should be exercised when administering tamsulosin to patients with severe renal insufficiency (endogenous creatinine clearance of less than 10 mL/min) as the clinical and pharmacokinetic profile of tamsulosin in these patients have not been fully studied. Although changes in the plasma concentration of the unbound active drug is minimal or none at all, caution should still be exercised when tamsulosin is administered in patients with severe hepatic insufficiency and the elderly since there is a definite though minimal decrease in the clearance of tamsulosin in these patients.
Tamsulosin is not intended to be used in women or children.

General: Asthenia.
Head and Neck: blurring of vision, dry mouth, rhinitis.
Skin: Rash, pruritus, urticaria, angioedema.
Central Nervous System: Dizziness, insomnia, headache, drowsiness, syncope.
Cardiovascular: Palpitations, orthostatic hypotension, pedal edema.
Gastrointestinal: Constipation, diarrhea, nausea and vomiting.
Reproductive System: Abnormal ejaculation, priapism.

Concomitant administration of cimetidine with tamsulosin resulted in a moderate increase in plasma levels of tamsulosin and should therefore be used with caution particularly at doses higher than 400 mcg per day. Concomitant administration of furosemide led to a slight and clinically insignificant decrease in the plasma level of tamsulosin and would not require any dose adjustment. Concomitant administration of diclofenac or warfarin may increase the elimination rate of tamsulosin though drug-drug interaction studies have yet to produce conclusive results. Though a study has shown that the concomitant administration of tamsulosin with nifedipine, atenolol or enalapril in stable hypertensive patients did not necessitate any dose adjustment of the anti-hypertensive medications, there is a theoretical risk of an enhanced hypotensive effect when it is given concurrently with drugs which may reduce blood pressure especially other alpha adrenergic blockers but which will also include anesthetic agents, calcium channel blockers and beta blockers.

Store at temperatures not exceeding 30°C.

Drugs for Bladder & Prostate Disorders

G04CA02 - tamsulosin ; Belongs to the class of alpha-adrenoreceptor antagonists. Used in the treatment of benign prostatic hypertrophy.

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