Can tiotropium (Spiriva) affect eye pressure adversely? The question concerns a patient with both a

Fråga: Can tiotropium (Spiriva) affect eye pressure adversely? The question concerns a patient with both asthma and severe open-angle glaucoma.

Sammanfattning: On a pharmacological basis, the risk of ocular side-effects mediated by anticholinergic action, should be at least similar for tiotropium, as compared with ipratropium. However, this risk only applies to patients with closure-angle glaucoma.

Svar: Tiotropium is a long-acting anticholinergic bronchodilator, administered as a dry-powder for oral inhalation (1).

No report of tiotropium induced ocular side-effects has been found in the literature or in the side-effect registers of Sweden and WHO. However, this is hardly to be expected, as the substance only recently was introduced into the market.

For the structural analogue, and very well documented drug, ipratropium (Atrovent), there are a few reports concerning mydriasis, increased ocular pressure or angle-closure glaucoma in predisposed patients who inadvertedly administered the drug to the eye. This effect is considered to be mediated by binding to muscarinic M3 receptors in the iris sphincter muscle. Only patients with closure-angle glaucoma is predisposed to this adverse effect (1,2).

The duration of action of tiotropium in vivo is substantially longer than that of ipratropium, most likely attributed to a much slower dissociation from the muscarinic M3 receptor (1). Therefore, from a pharmacological point of view, the risk of ocular side-effects in patients with angle-closure glaucoma should be similar, or greater, for tiotropium.

In the present case, with a patient with open-angle glaucoma, tiotropium can probably be used safely. 1 Micromedex(R) Healthcare Series: Micromedex Inc., Englewood, Colorado (Edition expires 12/2002) 2 Hardman JG, Limibrd LE, Goodman Gilman A, editors. Goodman & Gilman´s The pharmacological basis of therapeutics. 10th ed. New York: McGraw-Hill; 2001