Psychotic symptoms emerging after use of antibiotics have been reported occasionally. This include psychosis as well as mania with psychotic symptoms ( = antibiomania). Penicillin associated psychosis is also known as Hoigne syndrome. How antibiotics cause psychosis is not well understood. It is possible that GABA antagonism ( mainly by fluroquinolone ) , inhibition of prostaglandin synthesis ( = increase in dopamine) , and N-methyl-D-aspartate (NMDA) receptor hypo functioning ( due to depletion of D alanine producing intestinal flora) may be involved.
Infection itself can be associated with psychotic symptoms. UTI in the context of delirium and dementia is a well-known/ common example. Studies suggest that UTI can be the commonest cause for unrecognised medical condition on admission in geriatric patients with psychotic symptoms.
Safinaz Mostafa, and Brian J. Miller conducted a systematic review of cases of antibiotic-associated acute psychosis during treatment of a UTI and evaluated the strength of the association for each case using the guidelines for evaluation of drug-associated events.
They identified 15 cases of antibiotic- associated psychosis during treatment of UTI. These were associated with: fluoroquinolones (n = 8), trimethoprim-sulfamethoxazole (n = 5), and penicillins (n = 2). Patients were on antibiotics for a mean 4.8 days before psychosis emerged. Two had a previous history of antibiotic related psychosis. All patients had some form of psychiatric history.
Psychotic symptoms included hallucinations (n = 12), delusions (n = 9), disorganization (n = 5), and catatonia (n = 3) .
80% of cases with trimethoprim- sulphamethoxazole was considered as highly suggestive of causation. 60% of all cases were considered as strongly suggesting antibiotic to cause psychosis. 33% were moderately suggestive of this.
In most cases onset and resolution of psychosis occurred within 1 week of initiation or discontinuation of the antibiotics. Half did not require antipsychotic treatment. In 3 cases, a recurrence of psychosis after re challenge with the same antibiotic provides strong support to the notion that antibiotics could cause psychotic states.
Limitations: Small case series. Cases associated with UTI treatment alone included.