Flomax (tamsulosin) usually starts working within a few days, with some symptom relief often noticed within the first week. However, it can take up to about a month for the full effects to be felt. The medication reaches peak levels in the bloodstream about 4-5 hours after taking it, but symptom improvement often gradually increases over the first weeks of treatment. Patients typically notice less frequent and urgent urination starting within the first week, and significant symptom relief after about one month of consistent use. Factors like age, body weight, overall health, and how the body metabolizes the drug can affect how quickly it works. Flomax is normally taken once daily, often at night to reduce side effects like dizziness during the day and to improve nighttime symptoms.