Patient experience of the transition from Xalatan to generic latanoprost

Sir, We write in response to Mr Dubois and Ms Titcomb regarding the controversy over the switch from Xalatan to generic latanoprost.1, 2 We prospectively studied our patients' experience and the impact of generic use on our population. We also investigated the potency of generics versus Xalatan. Patients with ocular hypertension and primary open angle glaucoma treated with Xalatan monotherapy were recruited between March and September 2012. At baseline visit, intraocular pressure (IOP) was recorded, and a questionnaire designed to acquire information on practical issues regarding drop application, side effect profile, and patient preference, was issued. At review in clinic (between 3 and 6 months later), IOP was recorded and questionnaires were collected. Sixty-five patients were recruited, of whom 48 were women, with an average age of 75±9.02 years. Fifty-one completed questionnaires, of whom 76% were using generics. Patients found Xalatan easier to instil (X2=14.96; P 0.1). Generic bottles failed to last a month for 20% patients (nonspecific to different manufacturers). Patients commented that: multiple drops fall at a time or drops run down their face; bottles fail to last a month, causing distress at the perceived wasting of resources; bottle is difficult to open or cannot be used with a dispensing aid. Overall, 75% of patients preferred Xalatan and 22% wished to recommence Xalatan. IOP data were complete for 45 eyes, with no statistical difference between Xalatan and generics (t=1.37; P>0.01); however, individual patients had reduced control of IOP on generic latanoprost (Figure 1). Figure 1 Comparison of IOP on Xalatan and generic latanoprost with solid line indicating identical pressures. Our study provides confirmation of the points raised in Mr Dubois and Ms Titcomb's articles and clarifies our population's experience. Our patients prefer Xalatan and tolerate it better. The debate of IOP control cannot be concluded with this small study as, although the population has statistically insignificant changes of IOP, individual patients lose control. This will ultimately have impact on the clinician's time, patient management, and the economy of glaucoma care.