Welcome dear! Thanks for consulting me at virtual clinic. I have carefully worked through your case, and I can realize your health worries. Being your physician, I assure you not to worry as I will take care all of your medical concerns. Losartan causes bloating, gastric issues but not any weight gain. What it causes is edema and swelling which can wrongly be taken as getting weight. It causes hypoglycemia, and patient eats more because of low glucose levels. It may lead to weight gain.   Olmesartan is same category drug better than losartan in many perspectives. But which medicine you need is never decided the way you are trying to. Why I am saying that is you have not given your Blood pressure readings recorded, most of the times. If you need further, detailed and quick assistance related to any health issues, feel free to ask me a question directly from my profile. You can also attach Lab reports and pictures with direct question. May you get very well soon and have a wonderful time ahead. Please don t forget to give your valuable feedback and five star rating, to help me assist you in a better way. Click at I Find This Answer Helpful. Please, write a review about your experience with me.   Regards! DR. HANIF PHILADELPHIA, USA