Sir,

Intraoperative floppy iris syndrome (IFIS) consists of a triad of flaccid and billowing iris, iris prolapse through the surgical incisions, and progressive intraoperative pupil constriction. It is associated with the use of systemic α1-adrenoceptor (AR)-blocking agents, including tamsulosin, terazosin, doxazosin, and labetalol.1

We present a new case of typical IFIS occurring in a patient taking quetiapine, one of the most commonly used antipsychotic agent approved for the treatment of schizophrenia and bipolar disorder.

Case report

A 59-year-old woman with Alzheimer’s disease presented with cataract in both eyes. The patient’s history did not reveal any other systemic diseases, eye trauma, or previous ocular surgery. Preoperatively, the pupil dilated to 5.0 mm.

During the phacoemulsification procedure, characteristics of IFIS developed. Miosis and floppy iris responded moderately to intracameral adrenaline. Phacoemulsification was completed carefully and intraocular lens was successfully implanted into the capsular bag.

While reviewing the patient’s medication, we noticed that she had been on memantine 10 mg/day for 3 years for dementia and quetiapine 100 mg/day for 1 year for dementia-associated psychosis.

Comment

The patient was using two different drugs: an N-methyl-D-aspartate (NMDA) postsynaptic receptor antagonist, memantine, and an antipsychotic, quetiapine. Memantine has been shown to block the effects of glutamate at NMDA receptors and has no action on αARs. Thus, the most likely agent for developing IFIS was quetiapine in this patient.

Antipshotic zuclopenthixol was reported to be associated with IFIS.2 We were also previously faced with a similar problem with chlorpromazine, which is a typical antipsychotic agent.3 Typical antipsychotics have been largely supplanted by the atypicals because of the latter’s greater safety and tolerability.4 These agents produce extensive blockade of serotonin (5-HT)2A receptors, stimulation of 5-HT1A receptors, and blockade in dopamine D2 receptors. They also have an antagonistic effect on α1-ARs, which is especially prominent with quetiapine.5 Its use was previously reported to be associated with incomplete IFIS.5

In conclusion, surgeons should keep in mind the possibility of IFIS in patients using antipsychotics with prominent α1 receptor-blocking activity. Careful history must be elicited to detect the current or past use of these commonly prescribed group of drugs.