This article is professionally written by Pharmacist Huỳnh Xuân Lộc, Department of Pharmacy, Vinmec Central Park International General Hospital
Tamsulosin is a selective alpha-1 adrenergic receptor antagonist medication that helps relax the smooth muscles of the prostate and urethra. To ensure effective treatment, patients need to follow the instructions given by their doctor or pharmacist.
1. How does Tamsulosin work?
Tamsulosin, commonly known by the brand name Harnal Ocas, is a medication that belongs to the selective alpha-1 adrenergic receptor antagonists group. Tamsulosin helps to relax the smooth muscles of the prostate and urethra, facilitating easier urination and alleviating the symptoms of urinary difficulty in patients with benign prostatic hyperplasia (BPH).
In BPH, the prostate gland enlarges and compresses the urethra, obstructing the flow of urine. This condition often makes it challenging for patients to start urinating or results in a weak urine stream and frequent urination. Tamsulosin does not reduce the size of the prostate but helps to relieve the symptoms of the condition, thereby improving the quality of life for patients.
2. Proper use of Tamsulosin
Tamsulosin is a prescription medication that should only be used under the guidance of a urology specialist. Self-medicating with Tamsulosin can increase the risk of experiencing side effects or harmful drug interactions and may also result in inadequate control of the condition or failure to detect other diseases with similar symptoms.
Tamsulosin should not be used by individuals who have a history of hypersensitivity to this active ingredient or any other components of the medication, those with severe liver failure, or those with a history of orthostatic hypotension. Patients should inform their doctors about any ongoing medical conditions, especially liver, kidney, cardiovascular, or circulatory disorders.
If the patient is planning to undergo eye surgery for conditions such as cataracts or glaucoma, it is crucial to inform the ophthalmologist of the current or recent use of Tamsulosin. This is because Tamsulosin can cause Intraoperative Floppy Iris Syndrome (IFIS), a serious eye complication during surgery. Ophthalmologists will consider the choice of medication and surgical techniques to prevent this complication. Patients should also consult with their urologist to decide whether to continue or temporarily discontinue Tamsulosin during the planned surgery period.
Tamsulosin can interact with other medications, altering their effectiveness or causing unwanted side effects. Therefore, patients should list all medications they are currently taking or have recently taken to their doctor for appropriate choices. Medications to be aware of include:
• Diclofenac (anti-inflammatory pain reliever) or Warfarin (anticoagulant) can increase the rate at which Tamsulosin is eliminated from the body;
• Verapamil and Diltiazem (antihypertensives, antiarrhythmics) can interact to increase their concentration levels;
• Ketoconazole, Itraconazole (antifungal drugs) can increase the blood levels of Tamsulosin;
• Other alpha-1 adrenergic receptor antagonists like Doxazosin, Indoramin, Prazosin, Alfuzosin can increase the risk of hypotensive side effects;
• Anesthetics during surgery or dental procedures can increase the risk of hypotension.
Changes in the elimination rate or concentration of these drugs in the blood can affect treatment and increase the risk of side effects for patients taking them concurrently.
3. Side effects when using Tamsulosin
As with any medication, Tamsulosin can cause side effects in a small group of users. Serious side effects are rare or very rare, but if they occur, you should stop taking the medication and seek medical attention immediately. Notable reactions to watch out for include:
• Allergic reactions, severe sudden inflammation on the skin or mucous membranes (rash, redness, peeling skin, etc.);
• Swelling of the skin, around the mouth, or in the mucous membranes of the mouth and throat;
• Prolonged, uncontrolled, and painful erection;
• Severe skin redness.
Additionally, two common and less serious side effects (occurring in ≤ 10% of cases) include dizziness, especially when changing positions suddenly, or ejaculation disorders (a condition where semen does not exit the body but instead reverses back into the bladder). This retrograde ejaculation is harmless.
Other potential side effects of Tamsulosin include rapid heartbeat, headache, constipation, nausea, vomiting, and nasal congestion or runny nose, occurring in less than 1% of users.
While there are no reports indicating that Tamsulosin affects the ability to drive or operate machinery, some users may experience symptoms like blurred vision, dizziness, or fainting.
Patients should be mindful of these side effects or any other reactions suspected to be caused by the medication and inform their doctor during periodic check-ups or sooner if the symptoms persist and affect their quality of life.
4. Some precautions when using Tamsulosin
Use Tamsulosin as directed by your doctor, typically once a day. Do not change the dosage without consulting your healthcare provider. Swallow Tamsulosin whole with water or another liquid; do not chew or crush it as this can affect the absorption of the active ingredient.
If you miss a dose, take it as soon as possible on the same day. If more than 24 hours have passed since the missed dose, skip it and take the next dose as scheduled. Do not take a double dose to make up for the missed one. In case of an overdose, seek medical assistance immediately.
Tamsulosin is not intended for use in women, except in specific cases as determined by a doctor. Tamsulosin is a prescription medication and should only be used under the guidance of a urology specialist. Self-medication is not recommended.
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