Can drinking cranberry juice really help with cystitis irritation?

No: Can make cystitis irritation worse. Cranberry juice is only of use in preventing cystitis as it interferes with bacteria adhering to bladder lining. Acidity of cranberry juice can be quite irritating to the bladder.

Try antibiotics.: Cranberry juice might help produce more urine, which can get infection out somewhat, but antibiotics are more likely to eliminate infection, if used wisely. Depending on the infection, different antibiotics are used. Trimethoprim-sulfamethoxazole (tmp-smx), is often used for acute cystitis but examination by your physician is best to determine if you have cystitis, and if so, the best treatment.