Drug information of Tamsulosin
Mechanism of effect
Tamsulosin is a selective antagonist at alpha-1A and alpha-1B-adrenoceptors in the prostate, prostatic capsule, prostatic urethra, and bladder neck.
Tamsulosin is a selective antagonist at alpha-1A and alpha-1B-adrenoceptors in the prostate, prostatic capsule, prostatic urethra, and bladder neck. At least three discrete alpha1-adrenoceptor subtypes have been identified: alpha-1A, alpha-1B and alpha-1D; their distribution differs between human organs and tissue. Approximately 70% of the alpha1-receptors in human prostate are of the alpha-1A subtype. Blockage of these receptors causes relaxation of smooth muscles in the bladder neck and prostate, and thus decreases urinary outflow resistance in men.
Absorption of tamsulosin HCI from capsules 0.4 mg is essentially complete (>90%) following oral administration under fasting conditions. Vd is 16 L [intravenous administration to ten healthy male adults]. Protein binding: 94%-99%. Tamsulosin HCI is extensively metabolized by cytochrome P450 enzymes in the liver, however, the pharmacokinetic profile of the metabolites in humans has not been established. Tamsulosin hydrochloride is extensively metabolized by cytochrome P450 enzymes in the liver and less than 10% of the dose is excreted in urine unchanged. The metabolites of tamsulosin hydrochloride undergo extensive conjugation to glucuronide or sulfate prior to renal excretion. On administration of the radiolabeled dose of tamsulosin hydrochloride to four healthy volunteers, 97% of the administered radioactivity was recovered, with urine (76%) representing the primary route of excretion compared to feces (21%) over 168 hours. Half life: 5-7 hours. Clearance: 2.88 L/h.
Drug indicationsBenign Prostatic Hyperplasia
Usual Adult Dose for Benign Prostatic Hyperplasia Initial Dose: 0.4 mg orally once a day Maximum Dose: 0.8 mg orally once a day.
Drug contraindicationshypersensitivity to drug or its components.
Side effectsnausea , Headache , insomnia , chest pain , dizziness , Blurred vision , Diarrhea , asthenia , Rhinitis , Cough , sinusitis , impotence , Infections , somnolence , back pain , pharyngitis , toothache , decreased libido , Abnormal ejaculation
InteractionsImatinib , Amiodarone , Aprepitant , Acetaminophen+caffeine , Acetaminophen+caffein+acetylsalic , Acetaminophan+caffeine+ibuprofen , Itraconazole , Clarithromycin , Chloroquine phosphate , Clozapine , Clomipramine , Quinidine , Miconazole , Nilotinib , Vardenafil , Verapamil , Voriconazole , Ketoconazole , Sertraline , Cinacalcet , Fluoxetine , Fluconazole , Phenoxybenzamine , Lidocaine , Tetracycline , Trazodone , Tranylcypromine , Desipramine , Duloxetine , Cimetidine , Isoniazid , Imipramine , Paroxetine , Posaconazole , Glutazone , Tadalafil , Dactinomycin , Sirolimus , Cyclosporine , Pyrimethamine , Doxazosin , ritonavir , nelfinavir , Tipranavir , Mibefradil , Nicardipine , cobicistat , Delavirdine , Alfuzosin , Lorlatinib , Troleandomycin , Naltrexone and Bupropion , tucatinib
The signs and symptoms of orthostasis (postural hypotension, dizziness, and vertigo) were detected more frequently in Tamsulosin hydrochloride capsule-treated patients than in placebo recipients. As with other alpha adrenergic blocking agents there is a potential risk of syncope . Patients beginning treatment with Tamsulosin hydrochloride capsules should be cautioned to avoid situations in which injury could result should syncope occur.
Points of recommendation
1-Patients should be told about the possible occurrence of symptoms related to postural hypotension, such as dizziness, when taking Tamsulosin hydrochloride capsules, and they should be cautioned about driving, operating machinery or performing hazardous tasks 2-Patients should be advised about the possibility of priapism as a result of treatment with Tamsulosin hydrochloride capsules and other similar medications. Patients should be informed that this reaction is extremely rare, but if not brought to immediate medical attention, can lead to permanent erectile dysfunction (impotence). 3-Prostate cancer and BPH frequently co-exist; therefore, patients should be screened for the presence of prostate cancer prior to treatment with Tamsulosin hydrochloride capsules and at regular intervals afterwards. 4-Patients considering cataract surgery should be advised to tell their ophthalmologist that they have taken Tamsulosin hydrochloride capsules 5-Patients should be advised not to crush or chew the Tamsulosin hydrochloride capsules.
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