FLOMAX 0.4™
tamsulosin hydrochloride
Presentation
Capsule 0.4mg: a capsule (elongated #2) with an orange body, olive green cap and imprinted with the Yamanouchi logo , followed by the product code number (701) on the body, and with the indication of the strength (0.4) on the cap.
Each capsule contains 0.4mg tamsulosin hydrochloride equivalent to 0.367mg tamsulosin, which can be identified as pale yellowish white, modified release granules.
Uses
Actions
Tamsulosin binds selectively and competitively to postsynaptic α
1-adrenoceptors, in particular to subtypes alpha1A and alpha1D. It brings about relaxation of prostatic and urethral smooth muscle.
FLOMAX 0.4 increases the maximum urinary flow rate. It relieves obstruction by relaxing smooth muscle in prostate and urethra.
It also improves the irritative symptoms in which bladder instability plays an important role.
These effects on storage and voiding symptoms are maintained during long-term therapy. The need for surgical treatment is significantly delayed.
Alpha1-blockers can reduce blood pressure by lowering peripheral resistance. No reduction in blood pressure of any clinical significance was observed during studies with FLOMAX 0.4.
Pharmacokinetics
Absorption
Tamsulosin is rapidly absorbed from the intestine and is almost completely bioavailable. Absorption of tamsulosin is reduced by a recent meal.
Uniformity of absorption can be promoted by the patient always taking FLOMAX 0.4 after the same meal.
Tamsulosin shows linear kinetics.
After a single dose of FLOMAX 0.4 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 humans tamsulosin is about 99% bound to plasma proteins and the volume of distribution is small (about 0.2L/kg).
Biotransformation
Tamsulosin has a low first pass effect, being metabolized slowly. Most tamsulosin is present in plasma in the form of unchanged medicine. It is metabolized in the liver.
In rats, hardly any induction of microsomal liver enzymes was seen to be caused by tamsulosin.
No dose adjustment is warranted in hepatic insufficiency.
None of the metabolites are more active than tamsulosin itself.
Excretion
Tamsulosin and its metabolites are mainly excreted in the urine with about 9% of a dose being present in the form of unchanged medicine.
After a single dose of FLOMAX 0.4 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).
Dosage and Administration
One capsule daily, to be taken after breakfast, or the first meal of the day.
The capsule should be swallowed whole and should not be crushed or chewed as this will interfere with the modified release of the active ingredient.
Contraindications
Hypersensitivity to tamsulosin hydrochloride or any other component of the product.
A history of orthostatic hypotension.
Severe hepatic insufficiency.
Warnings and Precautions
As with other alpha1-blockers, reduction in blood pressure can occur in individual cases during treatment with FLOMAX 0.4, as a result of which, very rarely, syncope can occur. At the first signs of orthostatic hypotension (dizziness, weakness), the patient should sit or lie down until the symptoms have disappeared.
Before therapy with FLOMAX 0.4 is initiated, the patient should be examined in order to exclude the presence of other conditions which can cause the same symptoms as benign prostatic hyperplasia. Digital rectal examination and, when necessary, determination of prostate specific antigen (PSA) should be performed before treatment and at regular intervals afterwards.
The treatment of severely renally impaired patients (creatinine clearance of < 10ml/min) should be approached with caution as these patients have not been studied.
Pregnancy And Lactation
Not applicable as FLOMAX 0.4 is intended for male patients only.
Effects On Ability To Drive And Use Machines
No data is available on whether FLOMAX 0.4 adversely affects the ability to drive or operate machines. However, in this respect patients should be aware of the fact that dizziness can occur.
Adverse Effects
The following adverse reactions have been reported during the use of FLOMAX 0.4: dizziness, abnormal ejaculation and, less frequently (1-2%), headache, asthenia, postural hypotension and palpitations.
Interactions
No interactions have been seen when FLOMAX 0.4 was given concomitantly with either atenolol, enalapril, or nifedipine. Concomitant cimetidine brings about a rise in plasma levels of tamsulosin, and furosemide a fall, but as levels remain within the normal range posology need not be changed.
In vitro
, neither diazepam nor propranolol, trichlormethiazide, chlormadinon, amitriptyline, diclofenac, glibenclamide, simvastatin nor warfarin change the free fraction of tamsulosin in human plasma. Neither does tamsulosin change the free fractions of diazepam, propranolol, trichlormethiazide and chlormadinon.
No interactions at the level of hepatic metabolism have been seen during in vitro studies with liver microsomal fractions (representative of the cytochrome P450-linked drug metabolizing enzyme system), involving amitriptyline, salbutamol, glibenclamide and finasteride. Diclofenac and warfarin, however, may increase the elimination rate of tamsulosin.
No cases of acute overdosage have been reported. However, acute hypotension could theoretically occur after overdosage in which case 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 sulphate, can be administered.
None.
None known.
Store below 30°C.
FLOMAX 0.4mg modified release capsules can be used up to four years after manufacture. The expiry date is printed on the package.
Prescription Medicine.
Strips containing 10 capsules per strip; three strips in a cardboard box.
Microcrystalline Cellulose, Methacrylic-acid - ethyl acrylate copolymer, Polysorbate 80, Sodium lauril sulfate, Triacetin, Calcium Stearate, Talc, Hard gelatin, Indigotine E132, Titanium dioxide E171, Yellow iron oxide E172 and Red iron oxide E172
