Tamsulosin Hydrochloride
Brand Name: Flomax
Generic Available
Common Dosage Forms:
Capsules: 0.4 mg
FDA Indications/Dosages:
Treatment of the signs and symptoms of benign prostatic hyperplasia (BPH): Starting dose is usually one 0.4 mg capsule daily given one-half hour following the same meal every day. For patients who do not respond to 0.4 mg daily after 2-4 weeks, increase dose to 0.8 mg or 2 capsules daily given one-half hour following the same meal every day.
Pharmacology/Pharmacokinetics: Benign prostatic hyperplasia (BPH) is a condition that is commonly found in men over the age of 50 years. BPH is caused by a slow increase in the size of the prostate gland, a small gland that sits below the bladder and surrounds the bladder output, and by an increase in the smooth muscle tone in the prostate and bladder neck. Symptoms include a weak urinary stream, a delay upon urination, frequent urination, a feeling that the bladder cannot be emptied, and a feeling of immediate urination. Tamsulosin is a selective alpha-adrenergic blocking agent for receptors found in the prostate. Blockage of prostate alpha-adrenergic receptors relax the prostate gland and bladder neck and result in increased urinary flow and a reduction in the symptoms of BPH. Peak plasma levels are reached in 4-5 hours under fasting conditions. The presence of food decreases bioavailability. Between 94-99% is bound to plasma proteins but no pharmacokinetic changes were seen when given with other drugs bound to plasma proteins. Following metabolism in the liver by cytochrome P450 enzymes, 76% is excreted in the urine.
Drug Interactions: Additive effects may be seen when used with other alpha-adrenergic blocking agents. Strong inhibitors of CYP3A4 (cimetidine, ketoconazole) decreases clearance and raises plasma levels of tamsulosin.
Contraindications/Precautions: Contraindicated in patients with known hypersensitivity to tamsulosin. Patients should be tested initially to rule out prostate carcinoma and confirm the diagnosis of BPH. Orthostatic hypotension may occur during therapy therefore patients should be warned about possible syncope and dizziness. Tamsulosin should not be used with other alpha-adrenergic blocking agents or in combination with strong inhibitors of CYP3A4. Rare cases of priapism can occur during treatment. Intraoperative Floppy Iris Syndrome has been observed during cataract and glaucoma surgery. Patients should tell their ophthalmologist that they have taken tamsulosin. Pregnancy Category B.
Adverse Effects: Headache (19%), dizziness (15%), rhinitis (13%), infection (10%), asthenia (9%), abnormal ejaculation (8%), back pain (7%), pharyngitis (6%), diarrhea (6%), chest pains (4%), cough (3%), somnolence (3%), insomnia (2%), nausea (2%), sinusitis (2%), and PRIAPISM (<1%). Adverse effects are slightly higher when 0.8 mg/day is given.
Patient Consultation:
Take dose one-half hour following the same meal every day. If a dose is missed, skip it and return to normal dosing schedule.
May cause dizziness, especially when rising from the sitting position. Use caution when performing any hazardous task.
Store in a cool, dry place away from sunlight.
Do not discontinue or skip therapy without first consulting physician.
Contact a physician if adverse effects become severe or bothersome.