Trip Answers

Question answered:16/05/06 Warning! this question is over two years old.

Most of the information we found seems to relate to antidepressant medication and acute angle closure glaucoma. For example, The BNF entry on antidepressants states that, “SSRIs should be used with caution in patients with … angle-closure glaucoma.” [1]

Costagliola et al, writing in the British Journal of Opthalmology in 1998, postulate that SSRIs may have an effect on IOP [intraocular pressure]humans on the basis of a number of case reports describing an association between SSRIs and acute angle closure glaucoma [AACG].

“… It is therefore possible that SSRIs could have an effect on IOP in humans. Consequently, we should look for raised IOP and open angle glaucoma as a side effect of SSRIs. A recent study has shown a significant short term rise in IOP after a single oral dose of the SSRI fluoxetine (Prozac). Twenty depressed patients were given either fluoxetine 20 mg or placebo in a randomised crossover blinded study, and fluoxetine was associated with a mean IOP elevation of over 4 mm Hg, lasting 6-8 hours.We have been unable to find any publication regarding the effect on IOP in the longer term, but we have recently become aware of previously unpublished data which partly address this issue.

In premarketing and subsequent clinical trials of fluoxetine, 585 adult patients of a wide age range have been assessed. Ophthalmological examinations were made at baseline, and again after a treatment period which ranged between less than 1 month and 24 months. "Five out of the 585 patients had a change in intraocular pressure... . One had a decrease in IOP which was determined to be clinically insignificant [29 year old female, dosage 20 mg/day, examined at 1 month]. Four patients experienced an elevation: in one patient the elevation was considered a normal diurnal variation [74 year old male, dosage 80 mg/day, examined at 2 months], in a second patient the elevation was felt to be related to angle closure [59 year old male, dosage 80 mg/day, examined at 1 month], the third patient acknowledged cocaine use prior to the examination and this was considered the probable explanation [37 year old male, dosage 80 mg/day, examined at 12 months], and the fourth patient had a l mm Hg rise with no probable extenuating circumstances [26 year old female, dosage 80mg/day, examined at 2 months]" (Dista Products Limited, personal communication).

Voluntary reporting of suspected adverse events with fluoxetine has identified a total of 63 cases of "glaucoma" in an estimated patient population of 21 million (Dista Products Limited, personal communication). The manufacturers of paroxetine are aware of four cases of AACG, six of "glaucoma (unspecified)", and one of raised IOP, in a UK patient population of over one million (SmithKline Beecham Pharmaceuticals, personal communication).

These data indicate that our understanding of the effect of SSRIs on IOP is still unclear. The demonstration of a short term IOP rise after a single fluoxetine dose implies that chronic dosage could lead to a sustained elevation of IOP.”

The authors do note:

“However, the manufacturer's own data suggest that this is not the case, in that less than 1% of patients showed any IOP change after treatment. The low incidence of reported glaucoma with SSRIs does not exclude a real effect: many clinicians may not suspect a particular drug to be a contributory factor when diagnosing a particular condition, especially if a causal relation has not been suggested in the literature. This is particularly true of open angle glaucoma, which is common and usually idiopathic, and of AACG, which is rarer but occurs in anatomically predisposed eyes.” [2]

A second article also provides an overview of the literature on antidepressants and AACG which may be accessed in full text by following the link in the references section. [3]

Given the lack of studies and information on the effects of antidepressants on open angle glaucoma, the NLH Q & A would suggest this be discussed with an ophthalmologist, cardiologist or referred to the Medicines Information service.

 

References
1. BNF. Section 4.4.3 Selective serotonin reuptake inhibitors. March 2006. (http://www.bnf.org/bnf/bnf/51/3351.htm?q=%22antidepressants%22).
2. Costaglione C, Mastropasqua L and Steardo l et al. Acute glaucoma, chronic glaucoma, and serotoninergic drugs. Br J Ophthalmol 1998;82:976 (http://bjo.bmjjournals.com/cgi/content/full/82/8/976a).
3. Croos R, Thirumalai S and Hasan S. Citalopram associated with acute angle-closure glaucoma: case report. BMC Opthalmology 2005;5(23). (http://www.biomedcentral.com/content/pdf/1471-2415-5-23.pdf).

---

DISCLAIMER: TRIPanswers is a collection of clinical questions and answers.  Each provider will have their own methodology in answering questions and these are likely not to be as rigorous as systematic review.  If you have any doubt as to the implications of this contact the Q&A Service Provider for further information. This document is presented for information purposes only. This document cannot and should not be used as a basis of diagnosis or choice of treatment, and is in no way intended to replace professional medical care or attention by a qualified practitioner. TRIPanswers and TRIP Database Ltd are not responsible or liable for, directly or indirectly, ANY form of damage whatsoever resulting from the use/misuse of information contained in or implied by this document.  Also, ensure you have read the terms and conditions for using the site.