Description

Tamsulosin hydrochloride modified release capsules 400 mcg

Urimax® 0.4 mg

Composition

Each capsule contains:
Tamsulosin Hydrochloride BP 400 mcg
(as modified release pellets)
Approved colours used in empty capsule shell.

Dosage Form
Capsules

Pharmacology

Pharmacodynamics

Pharmacotherapeutic group: Alpha,-adrenoceptor antagonist.

Preparations for the exclusive treatment of prostatic disease.

Mechanism of action:

Tamsulosin binds selectively and competitively to postsynaptic alpha,-receptors, in particular to the subtype alpha,„ which bring about relaxation of the smooth muscle of the prostate, whereby tension is reduced.

Pharmacodynamic effects:

Tamsulosin hydrochloride increases maximum urinary flow rate by reducing smooth muscle tension in prostate and urethra and thereby relieving obstruction.

It also improves the complex of irritative and obstructive symptoms in which bladder instability and tension of the smooth muscles of the lower urinary tract play an important role. Alpha,-blockers can reduce blood pressure by lowering peripheral resistance. No reduction in blood pressure of any clinical significance was observed during studies with tamsulosin hydrochloride.

Pharmacokinetics

Absorption^.

Tamsulosin hydrochloride is absorbed from the intestine and is almost completely bioavailable.

Absorption of Tamsulosin hydrochloride is reduced by a recent meal.

Uniformity of absorption can be promoted by the patient always taking tamsulosin hydrochloride after the same meal each day.

Tamsulosin shows linear kinetics.

After a single dose of tamsulosin hydrochloride in the fed state, plasma levels of tamsulosin peak at around 6 hours and, in the steady state, which is reached by day 5 of multiple dosing, Cmax in patients is about two thirds higher than that reached after a single dose. Although this was seen in elderly patients, the same finding would also be expected in young ones.

There is a considerable inter-patient variation in plasma levels both after single and multiple dosing.

Distribution:
In man, tamsulosin is about 99% bound to plasma proteins and volume of distribution is small (about 0.2 1/kg).

Biotransformation:

Tamsulosin has a low first pass effect, being metabolised slowly. Most tamsulosin is present in plasma in the form of unchanged drug. It is metabolised in the liver.

In rats, hardly any induction of microsomal liver enzymes was seen to be caused by tamsulosin.

In vitro results suggest that CYP3A4 and also CYP2D6 are involved in metaboliSm, with possible minor contributions to tamsulosin hydrochloride metabolism by other CYP isozymes. Inhibition of CYP3A4 and CYP2D6 drug metabolising enzymes may lead to increased exposure to tamsulosin hydrochloride (see Warnings and Precautions, and Drug Interactions).

No dose adjustment is warranted in hepatic insufficiency.

None of the metabolites are more active than the original compound.

Elimination:

Tamsulosin and its metabolites are mainly excreted in the urine with about 9% of a dose being present in the form of unchanged drug.

After a single dose of tamsulosin hydrochloride in the fed state, and in the steady state in patients, elimination half-lives of about 10 and 13 hours respectively have been measured.

The presence of renal impairment does not warrant lowering the dose.

Indications

Treatment of functional symptoms of benign prostatic hyperplasia (BPH).