Tamsulosin hydrochloride is a prescription medication belonging to a class of drugs known as alpha-blockers. Its primary purpose is to improve urinary flow by relaxing specific muscles in the lower urinary tract. It is not intended to treat high blood pressure, a function of some other alpha-blocker medications.
Medical Uses for Tamsulosin
Tamsulosin is most commonly prescribed to treat the symptoms of benign prostatic hyperplasia (BPH), a non-cancerous enlargement of the prostate gland that occurs in men as they age. BPH can cause the prostate to squeeze the urethra, causing difficulty starting urination, a weak stream, dribbling after urination, and a frequent or urgent need to urinate.
Tamsulosin is also used off-label to aid in the passage of kidney stones. By relaxing the muscles of the ureter, the tube that connects the kidney to the bladder, the medication can help a stone move through the urinary tract more easily and with less pain. Tamsulosin manages symptoms but does not provide a cure for the underlying conditions. It does not shrink the prostate, which may continue to enlarge.
How Tamsulosin Works
Tamsulosin works by selectively blocking alpha-1 adrenoceptors, prevalent in the smooth muscles of the prostate and bladder neck. Approximately 70% of the alpha-1 receptors in the prostate are of the alpha-1A subtype, the primary target for tamsulosin. This high selectivity allows the drug to improve urine flow while having less effect on blood vessels elsewhere in the body.
This blockade of alpha-1 receptors causes the smooth muscles in the prostate and at the opening of the bladder to relax. This relaxation reduces the restriction on the urethra, which can be visualized as easing the tension on a clamp that is pinching a hose. The result is an improved ability to empty the bladder and a reduction in urinary symptoms.
Proper Dosage and Administration
Tamsulosin is prescribed as a 0.4 mg capsule taken once per day, approximately 30 minutes after the same meal each day. Taking the medication with food helps increase its absorption and can reduce the likelihood of side effects like dizziness.
Swallow the capsule whole. Crushing, chewing, or opening the capsule can interfere with its modified-release design, causing the medication to be released into the body too quickly. If a dose is missed, it should be taken as soon as remembered. If it is nearly time for the next scheduled dose, the missed dose should be skipped.
Potential Side Effects and Warnings
Common side effects include dizziness, headache, and a runny nose. Some men may also experience issues with ejaculation, such as retrograde ejaculation where semen enters the bladder instead of exiting the body. These side effects are mild, but any persistent or bothersome symptoms should be discussed with a healthcare provider.
A primary concern is orthostatic hypotension, a sudden drop in blood pressure upon standing that can lead to severe dizziness or fainting. Patients should be cautious when rising and avoid situations where an injury could occur if they were to faint. Another serious consideration is Intraoperative Floppy Iris Syndrome (IFIS), a complication that can occur during cataract or glaucoma surgery. Patients must inform their eye surgeon they are taking or have taken tamsulosin before any eye procedure.
A rare but serious side effect is priapism, a painful erection that lasts for four hours or longer and requires immediate medical attention. Allergic reactions are also possible, and those with a known severe allergy to sulfa drugs may have an increased risk. Tamsulosin can interact with other medications, including certain antifungal drugs, antibiotics, and drugs for erectile dysfunction, which can alter its effects or increase the risk of side effects.