Cases That Test Your Skills

The paranoid business executive

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During Mr. R’s psychiatric hospitalization, olanzapine is titrated to 10 mg at bedtime. Clomiphene citrate is discontinued to limit any potential precipitants of mania, and amoxicillin/clavulanate is not restarted.

Mr. R gradually shows improvement in sleep quality and duration and becomes less irritable. His speech returns to a regular rate and rhythm. He eventually begins to question whether his fears were reality-based. After 4 days, Mr. R is ready to be discharged home and return to work.

The authors’ observations

The term “antibiomania” is used to describe manic episodes that coincide with antibiotic usage.8 Clarithromycin and ciprofloxacin are the agents most frequently implicated in antibiomania.9 While numerous reports exist in the literature, antibiomania is still considered a rare or unusual adverse event.

The link between infections and neuropsychiatric symptoms is well documented, which makes it challenging to tease apart the role of the acute infection from the use of antibiotics in precipitating psychiatric symptoms. However, in most reported cases of antibiomania, the onset of manic symptoms typically occurs within the first week of antibiotic initiation and resolves 1 to 3 days after medication discontinuation. The temporal relationship between antibiotic initiation and onset of neuropsychiatric symptoms has been best highlighted in cases where clarithromycin is used to treat a chronic Helicobacter pylori infection.10

Antibiotics implicated in inducing mania

While reports of antibiomania date back more than 6 decades, the exact mechanism by which antibiotics cause psychiatric symptoms is mostly unknown, although there are several hypotheses.5 Many hypotheses suggest some antibiotics play a role in reducing gamma-aminobutyric acid (GABA) neurotransmission. Quinolones, for example, have been found to cross the blood–brain barrier and can inhibit GABA from binding to the receptor sites. This can result in hyper-excitability in the CNS. Several quinolones have been implicated in antibiomania (Table 15). Penicillins are also thought to interfere with GABA neurotransmission in a similar fashion; however, amoxicillin-clavulanate has poor CNS penetration in the absence of blood–brain barrier disruption,11 which makes this theory a less plausible explanation for Mr. R’s case.

Continue to: Another possible mechanism...


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