HALO is the trade name, the generic name is tamsulosin hydrochloride, and it is taken at night mainly to enhance the efficacy and reduce the adverse reactions. 1. Enhance the therapeutic effect: Tamsulosin hydrochloride is used to treat symptoms such as frequent urination and increased nocturia caused by prostate hyperplasia. Taking it at night has the strongest therapeutic effect when the concentration of the drug peaks during the night time, which can better alleviate the phenomenon of increased nocturia, improve the patient’s adherence, and enhance the therapeutic effect. 2. Reduce adverse reactions: tamsulosin hydrochloride is an alpha receptor blocker, relaxes the urethral sphincter, relaxes the smooth muscle of small blood vessels, prone to cause postural hypotension, resulting in dizziness, blurred vision, and even falls, can be avoided during the rest period of the patient taking at night. Tamsulosin hydrochloride main adverse reactions are drowsiness, insomnia, rapid heart rate, nausea, vomiting, abdominal pain, diarrhea and so on. It is contraindicated for those who are allergic to tamsulosin hydrochloride, those with renal insufficiency, and those who work at heights. If you need to use Tamsulosin Hydrochloride, you need to use it reasonably under the guidance of a physician or pharmacist to avoid adverse effects.