Cialis contains tadalafil. It increases blood flow to penis so that an effective erection of penis occurs facilitating sexual performance. The common side effects of Cialis are headache, dyspepsia, dizziness, flushing, swelling of eyelids, eye pain, back pain, myalgia, visual disturbances, nasal congestion, sudden decrease or loss of hearing, tinnitus. Losartan and hydrochlorothiazide lowers blood pressure if your blood pressure is high. Cialis does not interact significantly with losartan and hydrochlorothiazide. You can continue these medicines together. Advice 1. Take Cialis at least 30 minutes before sexual activity. It can be taken with or without food 2. Take losartan and hydrochlorothiazide in day time 3. Regularly check your blood pressure. If your blood pressure goes below 90/50 mm Hg then do not take Cialis and contact your doctor for review of treatment 4. Seek immediate medical advice if erection last more than 4 hours 5. Discontinue and seek medical advice if there is sudden vision loss or decreased vision in one or both eyes or tinnitus, dizziness or sudden loss or decrease in hearing, while taking Cialis I hope this information will help you. I will be happy if you ask another question Thanks