Nitrofurantoin

First line for UTI

The modified release preparation is a cost effective option.

If used long term for prophylaxis:

monitor full blood count, renal function and liver function tests every 6 months
advise patients of the risk of pulmonary and hepatic fibrosis, peripheral and optic neuropathy, and to report symptoms if they develop during treatment.

See MHRA April 2023 - Nitrofurantoin: reminder of the risks of pulmonary and hepatic adverse drug reactions