Tamsulosin & Dutasteride is a combination of two drugs with complementary mechanisms of action to improve symptoms in patients with Benign Prostatic Hyperplasia (BPH). Tamsulosin Hydrochloride, an antagonist of alpha_1A-adrenoreceptors and Dutasteride, a dual 5 alpha reductase inhibitor (5ARI). Treatment of BPH with alpha₁-adrenoreceptor blocking agents and 5ARIs results in an improvement in urine flow rate and a reduction in symptoms of BPH.

Tamsulosin: An alpha1-adrenoreceptor blocking agent that affects the dynamic component of BPH by inhibiting alpha₁-adrenoreceptors in the stromal prostatic smooth muscle and bladder neck. Blockade of these adrenoreceptors can cause smooth muscles in the bladder neck and prostate to relax. Specifically, Tamsulosin exhibits selectivity for both alpha _1A and alpha _1D receptors over the alpha_1B-adrenoreceptor subtype. These three adrenoreceptor subtypes have a distinct distribution pattern in human tissue. Whereas approximately 70% of the alpha₁-receptors in human prostate are of the alpha _1A subtype, the human bladder contains predominantly the alpha _1D subtype while blood vessels express predominantly alpha _1B subtype. It is further believed that blockade of the alpha _1D subtypes in the human obstructed bladder may be responsible for reducing detrusor overactivity and subsequent relief of storage symptoms.

Dutasteride: A synthetic 4-azasteriod compound is a competitive and specific inhibitor of both Type I and Type II 5 alpha-reductase isoenzymes that affects the static component of BPH by inhibiting the conversion of Testosterone to Dihydrotestosterone (DHT) by the enzyme 5 alpha-reductase. 5 alpha-reductase exists as 2 isoforms, Type I and Type II, both of which are present in the prostate. It has been observed that compared to normal tissue, the expression of both isoenzymes are increased in BPH tissue. Dissociation from this complex has been evaluated under in vitro and in vivo conditions and is extremely slow. Dutasteride lowers DHT levels and leads to a reduction in prostatic volume, thereby treating an underlying cause of BPH. Dutasteride does not bind to the human androgen receptor.

Tamsulosin Hydrochloride & Dutasteride capsule is indicated in-

• Treatment of moderate to severe symptoms of benign prostatic hyperplasia (BPH).
• Reduction in the risk of acute urinary retention and surgery in patients with moderate to severe symptoms of BPH.

Adults (including elderly): The recommended dose is one capsule (Tamsulosin Hydrochloride 0.4 mg & Dutasteride 0.5 mg) taken orally approximately 30 minutes after the same meal each day. The capsules should be swallowed whole and not chewed or opened. Where appropriate, this capsule may be used to substitute concomitant Tamsulosin Hydrochloride and Dutasteride in existing dual therapy to simplify treatment. Where clinically appropriate, direct change from Tamsulosin Hydrochloride or Dutasteride monotherapy to this capsule may be considered.

Renal impairment: The effect of renal impairment on Tamsulosin-Dutasteride pharmacokinetics has not been studied. No adjustment in dosage is anticipated for patients with renal impairment.

Hepatic impairment: The effect of hepatic impairment on Tamsulosin-Dutasteride pharmacokinetics has not been studied so caution should be used in patients with mild to moderate hepatic impairment. In patients with severe hepatic impairment, the use of this capsule is contra-indicated.

Tamsulosin-Dutasteride combination is contra-indicated in women and children and adolescents, patients with hypersensitivity to Dutasteride, other 5-alpha reductase inhibitors, Tamsulosin (including Tamsulosin- induced angio-edema), soya, peanut or any of other the excipients, patients with a history of orthostatic hypotension and patients with severe hepatic impairment.

The most common adverse reactions reported in subjects receiving combination therapy were impotence, decreased libido, breast disorders (including breast enlargement and tenderness), ejaculation disorders and dizziness. The percentages of subjects with ejaculation disorders, decreased libido and impotence were higher in the combination therapy group compared with either monotherapy groups.

Overdose Effects

No data are available with regard to over dosage of Tamsulosin-Dutasteride combination. The following statements reflect the information available on the individual components.

Dutasteride: In volunteer studies, single daily doses of Dutasteride up to 40 mg/day (80 times the therapeutic dose) have been administered for 7 days without significant safety concerns. In clinical studies, doses of 5 mg daily have been administered to subjects for 6 months with no additional adverse effects to those seen at therapeutic doses of 0.5 mg. There is no specific antidote for Dutasteride, therefore, in suspected over dosage symptomatic and supportive treatment should be given as appropriate.

Tamsulosin: Acute overdose with 5 mg Tamsulosin Hydrochloride has been reported. Acute hypotension (systolic blood pressure 70 mm Hg), vomiting and diarrhoea were observed which were treated with fluid replacement and the patient could be discharged the same day. In case of acute hypotension occurring after over dosage 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.

Combination therapy should be prescribed after careful benefit risk assessment due to the potential increased risk of adverse events (including cardiac failure) and after consideration of alternative treatment options including monotherapies.

Cardiac failure: In two 4-year clinical studies, the incidence of cardiac failure was higher among subjects taking the combination of Dutasteride and an alpha blocker, primarily Tamsulosin, than it was among subjects not taking the combination. In these two trials, the incidence of cardiac failure was low (1%) and variable between the studies.

Effects on prostate specific antigen (PSA) and prostate cancer detection: Digital rectal examination, as well as other evaluations for prostate cancer or other conditions which can cause the same symptoms as BPH, must be performed on patients prior to initiating therapy with Tamsulosin-Dutasteride combination and periodically thereafter. Serum prostate-specific antigen (PSA) concentration is an important component in the detection of prostate cancer. Tamsulosin-Dutasteride combination causes a decrease in mean serum PSA levels by approximately 50%, after 6 months of treatment. Patients receiving Tamsulosin-Dutasteride combination should have a new PSA baseline established after 6 months of treatment. It is recommended to monitor PSA values regularly thereafter. Any confirmed increase from lowest PSA level while on Tamsulosin-Dutasteride combination may signal the presence of prostate cancer or noncompliance to therapy with Tamsulosin-Dutasteride combination and should be carefully evaluated, even if those values are still within the normal range for men not taking a 5 alpha-reductase inhibitor. In the interpretation of a PSA value for a patient taking Tamsulosin-Dutasteride combination, previous PSA values while on Dutasteride treatment should be sought for comparison. Treatment with Tamsulosin-Dutasteride combination does not interfere with the use of PSA as a tool to assist in the diagnosis of prostate cancer after a new baseline has been established. Total serum PSA levels return to baseline within 6 months of discontinuing treatment. The ratio of free to total PSA remains constant even under the influence of Tamsulosin-Dutasteride combination. If clinicians elect to use percent free PSA as an aid in the detection of prostate cancer in men undergoing Tamsulosin-Dutasteride combination therapy, no adjustment to its value appears necessary.

Prostate cancer and high grade tumours: Results of one clinical study in men at increase risk of prostate cancer revealed a higher incidence of Gleason 8-10 prostate cancers in Dutasteride treated men compared to placebo. The relationship between Dutasteride and high grade prostate cancer is not clear. Men taking Tamsulosin-Dutasteride combination should be regularly evaluated for prostate cancer risk including PSA testing.

Renal impairment: The treatment of severely renally impaired patients (creatinine clearance of less than 10 ml/min) should be approached with caution as these patients have not been studied.

Hypotension: Orthostatic- As with other alpha-blockers, a reduction in blood pressure can occur during treatment with Tamsulosin, as a result of which, rarely, syncope can occur. Patients beginning treatment with Tamsulosin-Dutasteride combination should be cautioned to sit or lie down at the first signs of orthostatic hypotension (dizziness, weakness) until the symptoms have resolved. In order to minimize the potential for developing postural hypotension the patient should be haemodynamically stable on alpha-blocker therapy prior to initiating use of PDE5 inhibitors. Symptomatic: Caution is advised when alpha adrenergic blocking agents including Tamsulosin are coadministered with PDE5 inhibitors (e.g. sildenafil, tadalafil, vardenafil). Alpha adrenergic blockers and PDE5 inhibitors are both vasodilators that can lower blood pressure. Concomitant use of these two drug classes can potentially cause symptomatic hypotension.

Intraoperative Floppy Iris Syndrome: Intraoperative Floppy Iris Syndrome (IFIS) has been observed during cataract surgery in some patients on or previously treated with Tamsulosin. IFIS may lead to increased procedural complications during the operation. The initiation of therapy with Tamsulosin-Dutasteride combination in patients for whom cataract surgery is scheduled is therefore not recommended. Discontinuing Tamsulosin 1-2 weeks prior to cataract surgery is anecdotally considered helpful, but the benefit and duration of stopping therapy prior to cataract surgery has not yet been established. Leaking Capsule: Dutasteride is absorbed through the skin, therefore, women, children and adolescents must avoid contact with leaking capsules. If contact is made with leaking capsules, the contact area should be washed immediately with soap and water.

Hepatic impairment: Tamsulosin-Dutasteride combination has not been studied in patients with liver disease. Caution should be used in the administration of Tamsulosin-Dutasteride combination to patients with mild to moderate hepatic impairment.

Breast neoplasia: Breast cancer has been reported in men taking Dutasteride in clinical trials and during the post-marketing period. Physicians should instruct their patients to promptly report any changes in their breast tissue such as lumps or nipple discharge. Currently it is not clear if there is a causal relationship between the occurrence of male breast cancer and long term use of Dutasteride.

Pregnancy & Lactation

Tamsulosin-Dutasteride combination is contra-indicated for use by women. There have been no studies to investigate the effect of Tamsulosin-Dutasteride combination on pregnancy, lactation and fertility. The following statements reflect the information available from studies with the individual components. Fertility: Dutasteride has been reported to affect semen characteristics (reduction in sperm count, semen volume, and sperm motility) in healthy men. The possibility of reduced male fertility cannot be excluded. Effects of Tamsulosin Hydrochloride on sperm counts or sperm function have not been evaluated.

Pregnancy: As with other 5 alpha reductase inhibitors, Dutasteride inhibits the conversion of testosterone to dihydrotestosterone and may, if administered to a woman carrying a male foetus, inhibit the development of the external genitalia of the foetus. Small amounts of Dutasteride have been recovered from the semen in subjects receiving Dutasteride. It is not known whether a male foetus will be adversely affected if his mother is exposed to the semen of a patient being treated with Dutasteride. As with all 5 alpha reductase inhibitors, when the patient’s partner is or may potentially be pregnant it is recommended that the patient avoids exposure of his partner to semen by use of a condom. Administration of Tamsulosin Hydrochloride to pregnant female rats and rabbits showed no evidence of foetal harm.

Lactation: It is not known whether Tamsulosin or Dutasteride are excreted in human milk.