You need to push fluids, preferably water, and also watch your sodium intake. Soda, for instance, is a no no. Canned products are another culprit when you are having these issues. Opioid effects. The side effects of opioids have effect on your urinary sphincter which an make it hard for you to pee. Some also may release histamine which may cause the redness. Drugs.com provides accurate and independent information on more than 24,000 prescription drugs, over-the-counter medicines and natural products. OxyContin is a brand-name version of the extended-release form of. They are different versions of the same drug. OxyContin and immediate-release oxycodone belong to a drug class called opioids. Hi. I'm on Percocet 7.5/325, 2 pills every 4 hours, for tonsillectomy pain. It is difficult for me to urinate while on this pill, and I don't know why? I read up that in men it can enlarge the prostate, making it difficult, but I'm a woman. Any ideas why this is happening to me? Thanks! Best Answer: Oxycodone is in the opiate family. These drugs work on pain receptors in the brain. In some people the receptors that allow the bladder to relax to allow you to urinate, get a bit too relaxed. Making it very hard for the detruser nerves to relax and allow the flow. The easiest thing to do for. Side Effects. Drug information provided by: IBM Micromedex. Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. The problem is the muscles are getting too relaxed, that's why you're finding it hard to urinate. These are best tips/adivce Princess can give. Opiates will keep all bodily fluids and matter inside the body, challenge to urinate, ejaculate, pass a bowel movement. I guess emesis is the exeception to the rule, but that never occured from opiates to me. Oxycodone can make it even harder for you to urinate, or make you unable to urinate. Your doctor may prescribe a lower dosage of this drug. Your doctor may prescribe a lower dosage of this drug.