- tamsulosin hydrochloride
POM: Prescription only medicine
This information is intended for use by health professionals
PosologyOne tablet daily, to be taken with or without food.
Paediatric PopulationThe safety and efficacy of tamsulosin in children <18 years have not been established. Currently available data are described in Section 5.1.
Method of administrationFor oral use. The tablet should be swallowed whole and should not be crunched or chewed as this will interfere with the prolonged release of the active ingredient.
Tabulated list of adverse reactions
|System Organ Class||Common >1/100, <1/10||Uncommon >1/1000, <1/100||Rare >1/10,000, <1/1000||Very Rare <1/10,000||Not known (cannot be estimated from the available data)|
|Nervous system disorders||dizziness (1.3%)||headache||syncope|
|Eye disorders||Vision blurred* Visual impairment*|
|Vascular disorders||orthostatic hypotension|
|Respiratory, thoracic and mediastinal disorders||rhinitis||Epistaxis*|
|Gastrointestinal disorders||constipation, diarrhoea, nausea, vomiting||Dry mouth*|
|Skin and subcutaneous tissue disorders||rash, pruritis, urticaria||angioedema||Stevens-Johnson syndrome||Erythema multiforme* Dermatitis exfoliative*|
|Reproductive system and breast disorders||ejaculation disorders including retrograde ejaculation and ejaculation failure||priapism|
|General disorders and administration site conditions||asthenia|
Reporting of suspected adverse reactionsReporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard
SymptomsOverdosage with tamsulosin hydrochloride can potentially result in severe hypotensive effects, dizziness and malaise. Severe hypotensive effects have been observed at different levels of overdosing.
TreatmentIn case of acute hypotension occurring after overdose, cardiovascular support should be given. Blood pressure can be restored and heart rate brought back to normal by lying the patient down. If this does not help, then volume expanders, and when necessary, vasopressors could be employed. Renal function should be monitored and general supportive measures applied. Dialysis is unlikely to be of help, as tamsulosin is very highly bound to plasma proteins. Measures, such as emesis, can be taken to impede absorption. When large quantities are involved, gastric lavage can be applied and activated charcoal and an osmotic laxative, such as sodium sulfate, can be administered.
Mechanism of action:Tamsulosin binds selectively and competitively to postsynaptic alpha1-receptors, in particular to the subtype alpha1A, which bring about relaxation of the smooth muscle of the prostate, whereby tension is reduced.
Pharmacodynamic effects:Flomaxtra XL increases maximum urinary flow rate by reducing smooth muscle tension in the prostate and urethra, 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. Alpha1-blockers can reduce blood pressure by lowering peripheral resistance. No reduction in blood pressure of any clinical significance was observed during studies with Flomaxtra XL.
Paediatric PopulationA double-blind, randomized, placebo-controlled, dose ranging study was performed in children with neuropathic bladder. A total of 161 children (with an age of 2 to 16 years) were randomized and treated at 1 of 3 dose levels of tamsulosin (low [0.001 to 0.002 mg/kg], medium [0.002 to 0.004 mg/kg], and high [0.004 to 0.008 mg/kg]), or placebo. The primary endpoint was number of patients who decreased their detrusor leak point pressure (LPP) to <40 cm H2O based upon two evaluations on the same day. Secondary endpoints were: Actual and percent change from baseline in detrusor leak point pressure, improvement or stabilization of hydronephrosis and hydroureter and change in urine volumes obtained by catheterisation and number of times wet at time of catheterisation as recorded in catheterisation diaries. No statistically significant difference was found between the placebo group and any of the 3 tamsulosin dose groups for either the primary or any secondary endpoints. No dose response was observed for any dose level.
AbsorptionFlomaxtra XL is formulated as an Oral Controlled Absorption System (OCAS) and is a prolonged release tablet of the non-ionic gel matrix type.Tamsulosin hydrochloride administered as prolonged release tablets is absorbed from the intestine. Under fasting conditions approximately 57% of the administered dose is estimated to be absorbed. A consistent slow release of tamsulosin is maintained over the whole pH range encountered in the gastro-intestinal tract with little fluctuation over 24 hours. The extent of absorption is increased by 64% and 149% (AUC and Cmax respectively) by a high fat meal compared to fasted. After a single dose of Flomaxtra XL in the fasted state, plasma levels of tamsulosin peak at a median time of 6 hours. In steady state, which is reached by day 4 of multiple dosing, plasma levels of tamsulosin peak at 4 to 6 hours in the fasted and fed state. Peak plasma levels increase from approximately 6 ng/ml after the first dose to 11 ng/ml in steady state. As a result of the prolonged release characteristics of Flomaxtra XL, the trough concentration of tamsulosin in plasma amounts to 40% of the peak plasma concentration under fasted and fed conditions. There is a considerable inter-patient variation in plasma levels, both after single and multiple dosing.
DistributionIn man, tamsulosin is about 99% bound to plasma proteins and volume of distribution is small (about 0.2 l/kg).
MetabolismTamsulosin 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 metabolizing enzymes may lead to increased exposure to tamsulosin hydrochloride (see Section 4.4 and 4.5).No dose adjustment is warranted in hepatic insufficiency.None of the metabolites are more active than the original compound.
EliminationTamsulosin and its metabolites are mainly excreted in the urine. The amount excreted as unchanged drug is estimated to be about 4 - 6% of the dose, administered as Flomaxtra XL.After a single dose of Flomaxtra XL, and in steady state, elimination half-lives of about 19 and 15 hours, respectively, have been measured.No dose adjustment is necessary in patients with renal impairment.
Linearity/non-linearityTamsulosin shows linear kinetics.
CoreMacrogol (containing butylhydroxytoluene)Magnesium stearate
Film-coatHypromellose Macrogol Yellow iron oxide (E172)
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