Why is olanzapine contraindicated in individuals with angle-closure glaucoma, although glaucoma is

Fråga: Why is olanzapine contraindicated in individuals with angle-closure glaucoma, although glaucoma is not listed in FASS (Swedish physician´s desk reference) as a known side-effect of olanzapine? A psychotic woman is successfully treated with olanzapine (Zyprexa). When the treatment started, the prescriber was unaware that the patient has a glaucoma.

Sammanfattning: Theoretically, olanzapine could aggravate an angle-closure glaucoma because of its anticholinergic profile. Since most glaucomas are open-angle, a specific diagnosis is of great importance. If the angle-closure glaucoma diagnosis is confirmed, a less anticholinergic neuroleptic, such as haloperidol, may be a safer choice.

Svar: No reports connecting olanzapine use with glaucoma were found in Drugline, Medline or standard pharmacological literature. Neither are any such cases known to the manufacturer, who confirms that the contraindication is based on the hypothetic line of reasoning (1). Since olanzapine is more prone to cause anticholinergic side effects compared to classical neuroleptics (2), it could theoretically trigger or aggravate an angle-closure glaucoma in predisposed patients.

Notably, most glaucomas are open-angle, and only about 5 % of all glaucomas are of the angle-closure type (3).