The vet gave him an antibiotic injection that should last 2 weeks, an anti-inflammatory injection that should last 24 hours, and anti-inflammatory drops do give him once daily for the next several days.

Also I've ordered him Hill's Prescription Diet C/D Multi Care Stress Adult Cat Food "specially formulated to support your cat's urinary health" and a water fountain to encourage him to drink more.

I just rang the vet again to see if he needs another home visit today, because he doesn't seem to be peeing...