Tamsulosin is in a group of drugs called alpha-adrenergic blockers. Tamsulosin relaxes the smooth muscles around your veins and arteries so that blood can more easily pass through them. It also relaxes the muscles in the prostate and bladder neck, to allow urine to flow out easily. It is used to improve urination in men with benign prostatic hyperplasia (prostate enlargement).
Before taking tamsulosin, tell your doctor if you are allergic to sulfa drugs. You may
also be allergic to tamsulosin. If you will be having cataract surgery, tell the surgeon
that you are taking tamsulosin. If you develop severe light-headedness or fainting, or if you have an erection of your penis that is painful or lasts longer than 4 hours, discontinue taking tamsulosin. Although tamsulosin should not be used by women, this drug is not expected to be harmful to an unborn baby.
Tamsulosin is usually taken once a day, approximately 30 minutes after a meal. Try to take this medication at the same time each day. If this medicine makes you dizzy, take it after your evening meal. Seek emergency medical attention if you think you have used too much of this medicine and experience symptoms of possible overdose. These may include severe light-headedness or fainting; a fast pulse; or cold, clammy skin.
Tamsulosin can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert. This is also the reason why alcohol use should be avoided, which may increase dizziness. You may feel dizzy when getting up from a sitting or lying position. Avoid standing up too quickly to keep from falling.
Stop using tamsulosin and get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Serious side effects may also appear which necessitate you to discontinue taking tamsulosin. These may include: penis erection that is painful or lasts 4 hours or longer;
severe dizziness; or fainting.
Other, less serious side effects may be more likely to occur. Continue using tamsulosin and talk with your doctor if you have any of these side effects: mild dizziness or drowsiness; sleep problems (insomnia); abnormal ejaculation, decreased sex drive; or
runny or stuffy nose. Talk to your doctor about any side effect that seems unusual.
Before taking tamsulosin, tell your doctor if you are taking cimetidine (Tagamet, Tagamet HB); or warfarin (Coumadin). If you are using any of these drugs, you may not be able to take tamsulosin, or you may need dosage adjustments or special tests during treatment. Inform your doctor about all the prescription and over-the-counter medications you use including vitamins, minerals, herbal products, and drugs prescribed by other doctors.
Tamsulosin HCl is (-)-(R)-5-[2-[[2-(o-Ethoxyphenoxy) ethyl]amino]propyl]-2-methoxybenzenesulfonamide, monohydrochloride. Tamsulosin HCl occurs as white crystals that melt with decomposition at approximately 230°C. It is sparingly soluble in water and in methanol, slightly soluble in glacial acetic acid and in ethanol, and practically insoluble in ether. Each Tamsulosin (tamsulosin HCl) capsule for oral administration contains tamsulosin HCl 0.4 mg, and the following inactive ingredients: methacrylic acid copolymer, microcrystalline cellulose, triacetin, polysorbate 80, sodium lauryl sulfate, calcium stearate, talc, FD&C blue No. 2, titanium dioxide, ferric oxide, gelatin, and trace amounts of shellac, industrial methylated spirit 74 OP, n-butyl alcohol, isopropyl alcohol, propylene glycol, dimethylpolysiloxane, and black iron oxide E172.
Tamsulosin has the following structural formula: