Prophylaxis with brimonidine prevents sharp increases in intraocular pressure (IOP) in patients who undergo intravitreal injections with anti-vascular endothelial growth factor (anti-VEGF), according to a new study.

"Most importantly, our findings demonstrate that brimonidine also plays a protective role by significantly reducing the risk of eyes reaching very elevated IOPs in the range of 70-80 mmHg, and that reduces the need for post-injection anterior chamber (AC) paracentesis, said Dr. Efrem Mandelcorn of the University of Toronto. "Given that administration of topical prophylaxis only 20 minutes prior to injection was shown to have a hypotensive effect, it can be easily incorporated into the routine of ophthalmologists in a busy practice," he told Reuters Health by email.

Dr. Mandelcorn and his colleagues conducted a randomized crossover trial of non-glaucomatous eyes undergoing intravitreal anti-VEGF injections, which were randomized to receive topical brimonidine tartrate 0.15% or no prophylaxis on one of two consecutive visits. The study included 58 eyes in 55 patients, for a total of 116 visits. 

Intraocular Pressure

Mean IOP was significantly lower with brimonidine prophylaxis immediately after anti-VEGF injection (T0) and at 10 (T10) and 20 (T20) minutes post-injection compared to no prophylaxis. IOP at T0 was 41.6 mm Hg without prophylaxis and 34.2 mmHg with prophylaxis. Significantly fewer eyes receiving prophylaxis had an elevation of 20 mmHg from baseline or an IOP higher than 55 mmHg at T0.

Two eyes that did not receive prophylaxis had IOPs above 70 mmHg, requiring AC paracentesis. A recent national survey found that as many as 65% of ophthalmologists likely had suspected or confirmed cases of elevated IOP in patients undergoing repeated anti-VEGF injections, Dr. Mandelcorn noted.

"Nonetheless, only 9% of our respondents measure IOP and 14% considered prophylaxis necessary for all patients." In his own practice, he said, he now routinely offers topical prophylaxis to all patients on extended anti-VEGF injection regimens. While guidelines recommend monitoring IOPs after anti-VEGF injections, they do not specifically recommend prophylaxis, or treatment options are limited to AC paracentesis after an IOP spike, Dr. Mandelcorn said.

"Moving forward, research investigating the long-term of intravitreal complications of anti-VEGF therapy and specific benefits of prophylaxis for post-injection IOP spikes, including objective reports of long-term retinal nerve fiber layer thickness and visual field changes, are needed, "I said.

I have noticed that IOP and their patients were considered to be at high risk of IOP spikes, such as those with glaucoma, from the study, but I still showed an increase in IOP after injection. "This suggests that you are not considered to be at risk 'are exposed to repeated fluctuations in very high IOP with anti-VEGF injections," Dr. Mandelcorn said.