Tamsulosin may take effect in about 7 hours after use and does not take several days. Tamsulosin is a commonly used drug for the treatment of prostate enlargement, belongs to a receptor blocker, mainly through the relaxation of bladder smooth muscle, to alleviate the symptoms of urinary frequency and urgency due to prostate enlargement. According to relevant studies, tamsulosin can reach the peak blood concentration within seven hours after taking the drug, and play a role in the relaxation of urethral smooth muscle, that is, the drug will take effect in a few hours, and its effect is generally four days after the drug to reach a stable level. In addition, due to the individual response to the drug is different, drug metabolism is also affected by the liver and kidney function, so the specific time of onset of action varies from person to person. Tamsulosin may cause dizziness, headache, postural hypotension and other adverse reactions after taking it, and it is contraindicated for those who are allergic to this product. This drug is a prescription drug, please use it as prescribed after evaluation by a specialist.