Atropt - Azopt substitution
- Catherine Dunlop
- Aust Prescr 2009;32:138
- 1 October 2009
- DOI: 10.18773/austprescr.2009.066
A 50-year-old female fitness instructor was referred for management of raised intraocular pressures. Gonioscopy revealed bilateral narrow angles so she was treated with bilateral peripheral iridotomies.
Topical medication was also required to achieve the desired intraocular pressures. Latanoprost caused irritable red eyes, and beta blockers were avoided because of a history of asthma. The patient was able to tolerate brinzolamide, a carbonic anhydrase inhibitor, with the brand name of Azopt.
The patient filled the second month's prescription in the late afternoon at her busy local pharmacy. This computer-generated script was for Azopt 1% twice a day to both eyes.
Noticing a different red top on the bottle, the patient checked the name was correct on the pharmacy label, which obscured the manufacturer's label on the bottle. She thought the red-topped bottle must be a 'generic brand'. She used the drops in both eyes that night.
In the morning, the patient telephoned complaining of bilateral large pupils, glare intolerance while driving to work and blurred vision in both eyes. She also mentioned her new red topped bottle. On examination, her pupils were fixed and dilated. The optic discs showed no pulsation or haemorrhages, and her vision corrected to normal in both eyes. The intraocular pressures were within the normal range and the peripheral iridotomies were patent.
After the drops were stopped, the patient's main problem was glare while driving. She was able to work as there was little reading involved. After five days, the glare and blur had significantly improved.
The patient had instilled Atropt, a brand of atropine. Using this anticholinergic drug in a patient with narrow angles in the anterior chamber can precipitate angle-closure glaucoma. Atropine causes irreversible dilatation of the pupil. The dilated peripheral iris then blocks the angle, causing high intraocular pressure, ischaemia of the optic nerve head and possible blindness.
Narrow angles are more common in Asian eyes1and older Caucasian eyes, secondary to cataract development. There is an increasing risk of asymptomatic narrow angles being present in our population. Reversible dilating drops, such as tropicamide for fundoscopy, still need to be used cautiously in patients who have had laser treatment. Laser iridotomies may not remain patent.
Azopt and Atropt eye drops are unfortunately similar in name. I have several thoughts which may help avoid this potentially blinding mix-up:
Health professionals can confuse drugs with similar brand names. This exposes patients to unnecessary harm. In the case of Atropt and Azopt the confusion can blind the patient. There is less chance of confusing the generic names, but if brand names are used the prescription should be clearly written and carefully read when dispensed.
Comment by Ian D Coombes, Senior Pharmacist, Safe Medication Practice Unit, Queensland Health, Brisbane
Serious adverse events secondary to the error of selecting and dispensing a similar sounding drug are not uncommon. The author raises a number of logical and sensible suggestions on how to reduce the risk of this error recurring.
Strategies to reduce similar errors have been identified by medication safety bodies nationally and internationally:
Ophthalmologist, Newcastle, NSW