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There are two main types of glaucoma: chronic open-angle glaucoma (90% of U.S. cases), and acute closed-angle glaucoma (10% of cases). The major concerns regarding antidepressants and glaucoma are regarding individuals who have an anatomic susceptibility to closed-angle glaucoma. This susceptibility is typically a shallow anterior chamber—a structural defect that causes a narrow angle between the iris and cornea where the aqueous humor circulates. Medications that dilate the pupils can cause this narrow angle to close, blocking drainage and precipitating acute and dangerous increases in intraocular pressure.
Tricyclic antidepressants and monoamine oxidase inhibitors cause pupil dilation and, therefore, can precipitate acute closed-angle glaucoma. They should be avoided in patients with a known structural susceptibility to this condition.
The newer antidepressants, such as SSRIs, venlafaxine, duloxetine, bupropion and mirtazapine, appear to be safer than TCAs and MAOIs, but there have been rare reported cases of acute closed-angle glaucoma precipitated by these agents. There is not enough data to conclude that any one of the newer antidepressants is safer than another in patients with this condition. These medications are not absolutely contraindicated in patients with known susceptibility to closed-angle glaucoma, but should be used with caution.
None of the antidepressants is contraindicated in patients with open-angle glaucoma, and there is not enough data to suggest that any one antidepressant is preferable in patients with this condition. However, there are case reports of slight increases in intraocular pressure caused by several of the antidepressants, including SSRIs and venlafaxine. It is, therefore, reasonable to assess intraocular pressure soon after starting any antidepressant in patients with closed-angle glaucoma.
References:
Tripathi RC, Tripathi BJ, Haggerty C: Drug – induced glaucoma's: mechanisms and management. Drugs safety 2003, 26(11):749-767.
Eke T, Carr S: Acute glaucoma, chronic glaucoma and serotonergic drugs. Br J Ophthalmol 1998, 82:976-979.
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