Dorzolamide

Dorzolamide, a methylthienothiopyran-2-sulfonamide, is a highly specific carboanhydrase inhibitor used for local glaucoma therapy. Dorzolamide is stable in solutions, has a high water solubility and is also lipophilic enough to penetrate the cornea. Dorzolamide binds highly specifically to the carboanhydrase (isoenzyme II) in the ciliary body. This leads to a decrease in aqueous humor secretion and thus to a reduction in intraocular pressure. A structurally related and similarly acting drug is brinzolamide.

Common side effects are: nausea, a bitter taste, headache, weakness and fatigue, on the eye: burning and stinging, superficial punctiform corneal inflammation, increased watering of the eyes.

From the allergological point of view, contact allergic conjunctivitis, severe therapy-resistant eyelid eczema and periorbital eczema have been described. Furthermore, systemic urticarial and anaphylactic reactions after dorzolamide (possibly in combination with timolol) have been reported (Kluger N et al. 2008). In a larger study (n=14) it became known that the eczematous changes first appeared on average 20.4 weeks after initiation of dorzolamide therapy (Delaney YM et aal. 2002). Dorzolamide has a long half-life of about 4 months (delayed subsidence of contact allergy after discontinuation of local treatment!)

Originally, carboanhydrase inhibitors were used as diuretics. The best known substance is acetazolamide (Diamox). A carboanhydrase-catalyzed reaction produces the aqueous humor of the eye, which is responsible for the intraocular pressure. Carboanhydrase inhibitors are successfully used as local therapeutic agents (in eye drops) to reduce intraocular pressure. In combination with the beta-blocker Timolol, dorzolamide is approved in Germany as the finished drug Cosopt® for the treatment of increased intraocular pressure (IOP) in patients with glaucoma.

1. Delaney YM et al (2002) Periorbital dermatitis as a side effect of topical dorzolamide. Br J Ophthalmol 86:378-380.
2. Kalavala M et al (2006) Allergic contact dermatitis from timolol and dorzolamide eye drops. Contact dermatitis 54:345.
3. Kluger N et al. (2008) Systemic contact dermatitis to dorzolamide eye drops. Contact Dermatitis 58:167-168
4. Lee SJ et al (2015) Allergic contact dermatitis caused by dorzolamide eyedrops. Clin Ophthalmol 9:575-577.
5. Linares Mata T et al (2005) Contact dermatitis caused by allergy to dorzolamide. Contact dermatitis 52:111-112.
6. Shimada M et al. (2001) Allergic contact dermatitis caused by allergy to dorzolamide eyedrops. Contact dermatitis 45:52.