Being completely unable to pass urine is a symptom that requires immediate medical evaluation rather than self-medication. While UTIs are typically treated with prescription antibiotics like nitrofurantoin, taking them will not immediately relieve a bladder blockage. Please visit an urgent care clinic or emergency department right away. A healthcare provider can safely drain your bladder to give you instant relief, perform a urine test, and prescribe the correct medication. This is a very common and highly treatable issue, so please do not panic, but do seek medical attention promptly to ensure your safety and comfort.