Finasteride and Floppy Iris Syndrome: What Role Can the Dermatologist Play?

Sir,

Finasteride is a 5α-reductase type 2 inhibitor commonly used by dermatologists, especially those specialized in trichology. Although it is safe and generally well tolerated, there are various side effects reported in the literature.

Intraoperative floppy iris syndrome (IFIS) is a not so well-known possible consequence of finasteride use, especially among dermatologists. It is mainly a problem encountered during cataract surgery although it can also lead to postoperative complications.[1] IFIS was first described in 2005 by Chang and Campbell[2] and is characterized by the triad of flaccid and billowing iris (“floppy”), a propensity for iris prolapse toward the incisions [Figure 1], and progressive intraoperative pupil miosis.

Figure 1

Iris prolapse through side port and main port

Although most commonly associated with tamsulosin, an association with finasteride has also been described, with the first reports dating back to 2007 in two men taking finasteride 5 mg/day for benign prostatic hyperplasia.[3] Then, IFIS was reported in a 47-year-old man taking finasteride 1 mg/day for androgenetic alopecia during the past 4 years.[4] Later on, large prospective studies also confirmed this association.[56] In these studies, patients had not received tamsulosin or other α-blocker, suggesting an independent effect for finasteride. In the most recent study with 319 patients, the multivariate analysis revealed that tamsulosin use (P = 0.004), finasteride use (P = 0.014), and increasing age (P = 0.006) were significantly associated with IFIS, with the adjusted odds-ratio for finasteride use being 3.94.[6]

There is not much data regarding the management of IFIS related to finasteride. Discontinuation of drugs with a causative relationship to IFIS does not seem to fully eliminate its risk although it could be helpful sometimes. It has been found that IFIS may still occur despite discontinuing α1-adrenergic receptor antagonists years before the surgery.[1] Some authors defend that drug dose modification may reduce the risk of IFIS, since a lower incidence of IFIS was reported in patients on tamsulosin in Japan, where the recommended dosage was lower than that used in Europe and in the United States.[7] Another possibility is to defer treatment with finasteride in patients with a known cataract or planned cataract procedure; if the patient is already taking the drugs, physicians should discuss with the ophthalmologist.[1] Some authors still defend that finasteride should be stopped before cataract surgery.[7]

Despite this varying data, what is important is to raise awareness of IFIS among physicians prescribing possible causative drugs, particularly dermatologists which commonly use finasteride. We should recognize that finasteride can cause IFIS and the dermatologist should advise the surgeon that the patient was or is taking this drug, as there are pre and intraoperative regimens – e.g., preoperative cycloplegia with atropine, low-flow fluids, iris retractors, and pupillary ring expanders – that can reduce IFIS' risk.[18] Most surgeons do not insist that these agents should be discontinued, as this has not been shown to prevent or decrease the severity of IFIS.[9]

With this letter, we aim to alert dermatologists for an existing relationship between finasteride and IFIS, providing knowledge based in recent literature data, to inform the ocular surgeon and promote a better practice.

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Conflicts of interest

There are no conflicts of interest.