If you see a lot of older male patients, it’s likely that you’ve often had a conversation about the ocular effects of Flomax (tamsulosin, Boehringer Ingelheim/Astellas Pharma), an oral medication for men who suffer from benign prostatic hypertrophy (BPH). Flomax, an alpha-1a blocker, decreases symptoms of BPH such as frequency, urgency, weak urine stream, difficulty in starting urine flow, dysuria and nocturia.
The decrease in BPH symptomatology observed with tamsulosin is directly related to the drug’s ability to preferentially antagonize alpha-1a receptors and, therefore, relax smooth muscle in the prostate and bladder neck. Although other non-subtype alpha-1 blockers exist, tamsulosin’s affinity and selectivity for the alpha-1a receptor subtype results in superior efficacy in treating BPH without the hypotensive side effects common with less selective agents.1 Unfortunately, it also relaxes the iris dilator muscle, leading to miosis.
In recent years, the use of tamsulosin has expanded to off-label indications in both men and women. Here is an overview.
The most common off-label use of tamsulosin is to assist in the passage of kidney stones by increasing urinary fluid volume and pressure as well as relaxing smooth muscle in the ureters.2 Studies have verified that tamsulosin increases the expulsion rate of kidney stones while decreasing the time to expulsion and the need for adjunctive pain management, hospitalization and surgical intervention.3
Tamulosin is also prescribed off-label to men and women to treat overactive bladder, to facilitate voiding in patients with and without multiple sclerosis (MS) and to treat patients with urinary retention.4,5 Like its mechanism of action in BPH, tamsulosin is effective by antagonizing alpha-1a receptors with subsequent relaxation of urinary track smooth muscle.6
The expanded use of tamsulosin is important to optometrists because of its well-established association with intraoperative floppy iris syndrome (IFIS). The condition, with its associated perioperative cataract surgery concerns, was first reported in 2005 by David F. Chang, M.D., and John R. Campbell, M.D.
IFIS is precipitated by the drug’s effect on the iris dilator smooth muscle and is characterized by poor pupillary dilation before surgery, progressive miosis during the procedure, iris movement and undulation hindering phacoemulsification, iris prolapse through the cataract incision site and posterior capsule rupture.
Most recently, an increased risk of postoperative complications has also surfaced regarding the use of Flomax. Patients who currently use the drug, and even patients who have used an alpha-1a blocker in the past, are more at risk for postoperative complications including retinal detachment, lost lens fragments and severe inflammation or infection.8
With the FDA’s approval of a generic tamsulosin formulation in 2010, more patients have greater access to the medication. Practitioners should also be aware of the FDA-approved branded combination product called Jalyn (dutasteride and tamsulosin hydrochloride, GlaxoSmithKline), which combines tamsulosin with the 5-reductase inhibitor dutasteride to reduce symptoms associated with BPH.
Another alpha-1a selective blocker, Rapaflo (silodosin, Watson), received FDA approval in 2008 and, as suspected, has had reports of IFIS. Non-subtype specific alpha blockers such as Hytrin (terazosin hydrochloride, Abbott Labs), Cardura (doxazosin mesylate, Pfizer), and Uroxatral (alfuzosin hydrochloride, Sanofi-Aventis) have had reports of IFIS but are rare compared with the alpha-1a selective products.
In order to decrease the surgical ophthalmic risks associated with alpha-1a blockers, eye care practitioners must take heed of the Boy Scout motto “be prepared.” Unfortunately, stopping the medication before surgery has not proven to lessen or halt IFIS and is generally not recommended. Knowledge of the patient’s previous or current use of an alpha-1a blocker, however, will allow the surgeon to take preoperative and intraoperative precautions, which will allow for fewer IFIS complications. Here are some recommendations for the management of IFIS.
Most ophthalmologists agree the biggest threat with a Flomax patient involves the inability to maintain good pupillary dilation during the surgery. In a survey of high-volume ophthalmologists skilled in managing IFIS, there are various recommendations for achieving and maintaining an adequate pupil size. The use of atropine 1% has been described three to seven days pre-op as well as the use of an intracameral epinephrine/lidocaine mixture. Both of these techniques increase pupillary dilation and decrease progressive miosis. Surgeons also recommend having iris hooks and/or capsular tension rings available in case their pharmacological approach fails.
Healon 5 (Abbott Medical Optics), as both a cohesive and dispersive viscoelastic agent, is the preferential viscoelastic for patients who exhibit IFIS. Its unique properties help to promote pupillary dilation and keep the iris from billowing and prolapsing into the incision sites.
Finally, some surgeons alter their phacoemulsification settings at various stages of the procedure in patients who exhibit IFIS. This often will result in a longer surgical case but a less complicated one.
With the increased and expanded use of tamsulosin and other alpha-1a antagonists for males and females alike, eye care practitioners should be diligent in reviewing each patient’s medication history and informing the surgeon when referring for cataract surgery. Asking your patient about current or previous urinary tract or prostate issues is an easy way to determine potential problems. This information is especially important for cataract surgeons, optometrists in surgical centers who provide pre- and postoperative care and primary care optometrists who are referring patients for surgery.
1. Lepor H. The evolution of alpha-blockers for the treatment of benign prostatic hyperplasia. Rev Urol. 2006;8(Suppl 4):S3-9.
2. Lipkin M, Shah O. The use of alpha-blockers for the treatment of nephrolithiasis. Rev Urol. 2006;8(Suppl 4):S35-42.
3. Al-Ansari A, Al-Naimi A. Efficacy of tamsulosin in the management of lower ureteral stones: a randomized double-blind placebo-controlled study of 100 patients. Urology. 2010 Jan;75(1):4-7.
4. Rietz A, Haferkamp A, Kyburz T, et al. The effect of tamsulosin on the resting tone and the contractile behavior of the female urethra: a functional urodynamic study in healthy women. 2004 Aug;46(2):235-40; discussion 240.
5. Chang SJ, Chiang IN, Yu HJ. The effectiveness of tamsulosin in treating women with voiding difficulty. Int J Urol. 2008 Oct;15(11):981-5.
6. Yasuda T, Yasuda K, Kamai T, et al. Combination of a cholinergic drug and an α-blocker is more effective than monotherapy for the treatment of voiding difficulty in patients with underactive detrusor. Int J Urol. 2004 Feb;11(2):88-96.
Additional references available at www.reviewofcontactlenses.com.
7. Chang DF, Campbell JR. Intraoperative floppy iris syndrome associated with tamsulosin (Flomax). J Cataract Refract Surg. 2005 Apr;31(4):664-73.
7. Bell CM, Hatch WV, Fischer HD, et al. Association between tamsulosin and serious ophthalmic adverse events in older men following cataract surgery. JAMA. 2009 May 20;301(19):1991-6.