 [ Symptoms ] i feel hot on the inside but no fever i have a stomach ache and my throat hurt and glands feel swollen [ Disease ] you are smart to ask this question grapefruit juice can cause drug concentration levels to rise in a person is system and the list of drugs that interact with grapefruit is on the rise the issue of grapefruit is impact on the body is uptake of levothyroxine honestly is a bit controversial some studies have concluded the affect of grapefruit on thyroid medications is minimal but some thyroid experts maintain you should avoid grapefruit entirely if you take thyroid medication your best bet is to check with your pharmacist or your health care provider for the latest research recommendations on this subject they can guide you regarding the best strategy for enjoying your grapefruit without affecting your medication wishing you well