Does Amitriptyline cause Glaucoma? (+3 Side effects)

This article will answer the question, “Does amitriptyline cause glaucoma?” We will also discuss the mechanism by which amitriptyline induces glaucoma, how to avoid glaucoma associated with amitriptyline, and the other possible side effects you might experience while using amitriptyline.

Does Amitriptyline cause glaucoma?

Yes, amitriptyline does cause glaucoma. Amitriptyline is a tricyclic antidepressant (TCA) that inhibits serotonin and norepinephrine reuptake. It is an FDA-approved drug that is used for the treatment of depression (1).

However, one of the side effects of amitriptyline is its anticholinergic effect, which makes it contraindicated in patients with glaucoma (2). Most side effects of amitriptyline result from its central and peripheral anticholinergic activity.

Mydriasis and cycloplegia are the two most frequent anticholinergic effects produced by amitriptyline on the eye, ultimately leading to the development of narrow-angle glaucoma. Therefore, it is suggested to use amitriptyline cautiously if you have a previous history of glaucoma (3).

Why does Amitriptyline cause glaucoma?

Amitriptyline causes glaucoma by increasing the intraocular pressure (IOP). In addition to the two main side effects of amitriptyline, which are mydriasis and cycloplegia, amitriptyline also blocks noradrenaline uptake and alpha-adrenergic receptors. All of these increase the intraocular pressure, ultimately leading to the development of glaucoma (5).

Intraocular pressure usually depends on the amount of aqueous humour in the interior chamber of the eye. Amitriptyline, a tricyclic antidepressant, produces its mood-elevating effect by increasing serotonin levels.

It has been speculated that this elevation in the serotonin levels may lead to mydriasis and narrow-angle conformation, which affect the aqueous humour circulation, causing an increase in intraocular pressure and ultimately leading to the development of glaucoma (5,6).

What does research suggest?

Although glaucoma is one of the potential adverse effects of amitriptyline, a  limited number of cases are reported in the literature that describe the link between amitryptiline and glaucoma. One of the research studies includes the cases of four patients who developed angle-closure glaucoma (ACG) upon using a small dose of amitriptyline (7).

In another survey, four patients out of 106 admitted to the Royal Victorian Eye and Ear Hospital for the treatment of acute narrow-angle glaucoma were found to be taking amitriptyline. All four patients were not previously diagnosed with glaucoma; therefore, no miotic eye drops were prescribed to them during their treatment with amitriptyline (3).

How is Amitriptyline-induced glaucoma managed in clinical settings?

The primary objective of managing amitriptyline-induced glaucoma in clinical settings is to decrease intraocular pressure, which is achieved through the following approaches:

• Miotic drugs such as pilocarpine and carbachol are frequently used in patients with open-angle and chronic narrow-angle glaucoma (3).
• Anticholinesterase drugs are also utilized, as these drugs cause miosis (pupil constriction) (3).
• Another approach to reducing intraocular pressure is decreasing aqueous humour production, often achieved using timolol maleate (a beta-blocker). Carbonic anhydrase inhibitors also decrease aqueous humour production by 40-60%; therefore, they manage open-angle glaucoma when other treatment options fail (3).
• For managing acute angle-closure glaucoma, a 4% pilocarpine solution is administered as two drops every 15 minutes for several hours (3).
• If Amitriptyline continues to cause ocular side effects, your doctor may taper it off and safely switch you to another medication. Just make sure you do not stop using Amitriptyline without consulting your doctor first.

How do you avoid amitriptyline-induced glaucoma?

To avoid amitriptyline-associated glaucoma, patients who are under consideration for amitriptyline therapy must be screened for a shallow anterior chamber.

This is done using a penlight test, a screening procedure for the narrow anterior chamber. Patients with a narrow anterior chamber or a previous history of chronic open or narrow-angle glaucoma can be treated safely with amitriptyline if their intraocular pressure is constantly monitored (3).

Your doctor might also add a miotic drug to your amitriptyline therapy, such as pilocarpine, to balance the anticholinergic effect (3).

Before initiating amitriptyline therapy, your doctor should assess you for the risk factors of narrow-angle glaucoma, which include farsightedness, cataracts, and a family history of glaucoma. If these risk factors are present, your clinician will refer you to an ophthalmologist before starting amitriptyline (3).

Your healthcare provider must inform you about the symptoms of acute angle-closure glaucoma while prescribing amitriptyline. If symptoms like nausea or vomiting occur with a sudden onset of blurred vision, pain around the eye, or rainbow-like halos, then you should immediately stop taking amitriptyline and consult with your healthcare provider (3).

Other ocular Side Effects of Amitriptyline

The most frequent ocular side effects of amitriptyline are mydriasis and cycloplegia, which lead to the development of glaucoma. However, you might experience other ocular side effects while using amitriptyline. Some of them are as follows (6):

• Dry eyes.
• Decreased Lacrimation.
• Blurred vision.
• Cataract.

Apart from the ocular side effects, amitriptyline has other adverse effects, which include dizziness, sedation, suicidal behaviour, weight gain, Qt prolongation, orthostatic hypotension, tachycardia, urinary retention, confusion, and delirium (1).

It is recommended to contact your healthcare provider if you are experiencing any of the side effects mentioned above.

Conclusion:

In this article, we have answered the query, “Does amitriptyline cause glaucoma?” We have also discussed the mechanism by which amitriptyline induces glaucoma, how to avoid glaucoma associated with amitriptyline, and other possible side effects you might experience while using amitriptyline.

References