Tamsulosin is an alpha-blocker.

Take tamsulosin by mouth 30 minutes after eating the same meal each day.

Ask your health care provider any questions you may have about how to use tamsulosin and use exactly as directed.

Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Back pain; blurred vision; cough; decreased sexual ability; diarrhea; dizziness; drowsiness; lightheadedness; runny or stuffy nose; sinus inflammation; trouble sleeping; weakness.

Seek medical attention right away if any of these SEVERE side effects occur:
Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); chest pain; fainting; fever, chills, or persistent sore throat; irregular heartbeat; prolonged, painful erection; severe of persistent dizziness.

This is not a complete list of all side effects that may occur. If you have questions or need medical advice about side effects, contact your doctor or health care provider.

Tell your health care provider if you are taking any other medicines, especially any of the following:

Alpha-blockers (eg, prazosin) or phosphodiesterase inhibitors (eg, sildenafil) because symptoms of low blood pressure (eg, severe dizziness, lightheadedness, and fainting) may occur
Azole antifungals (eg, ketoconazole), cimetidine, or serotonin specific reuptake inhibitors (eg, fluoxetine) because they may increase the risk of tamsulosin side effects

Warfarin because the risk of side effects may be increased

This may not be a complete list of all interactions that may occur. Ask your health care provider if tamsulosin may interact with other medicines that you take.

If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include severe headache, dizziness, and fainting.

Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

if you are pregnant, planning to become pregnant, or are breast-feeding

if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement

if you have allergies to medicines or other substances

if you have had a severe allergic reaction (eg, severe rash, hives, difficulty breathing, dizziness) to any sulfonamide (sulfa) medicine, such as acetazolamide, celecoxib, certain diuretics (eg, hydrochlorothiazide), sulfonylureas (eg, glyburide), probenecid, sulfamethoxazole, valdecoxib, or zonisamide.

if you have a history of high blood pressure or prostate cancer

if you will be having eye surgery

Do not take a double dose to make up for a missed one.

Tamsulosin works by relaxing muscles in the prostate and bladder, which helps to improve urine flow and reduce symptoms of BPH.

Ask your doctor or pharmacist for more information.

Store it at room temperature and away from excess heat and moisture.

Tell your doctor or dentist that you take tamsulosin before you receive any medical or dental care, emergency care, or surgery.

Tamsulosin may rarely cause a prolonged, painful erection. This could happen even when you are not having sex. If this is not treated right away, it could lead to permanent sexual problems such as impotence. Contact your doctor right away if this happens.

Ask your health care provider any questions you may have about tamsulosin.