Metamizole as analgesic during panretinal photocoagulation in proliferative diabetic retinopathy

Abstract

 

Purpose

 

To evaluate the effectiveness of oral metamizole in reducing pain during panretinal photocoagulation (PRP) in patients with proliferative diabetic retinopathy (PDR).

 

Methods

 

Twenty patients from a single center (Department of Ophthalmology of Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo) with PDR and indication of bilateral PRP were recruited for a double-masked, controlled, prospective study. The exclusion criteria were: previous photocoagulation treatment, media opacity such as cataracts, corneal diseases or vitreous haemorrhage, unilateral PDR, chronic use of analgesics or history of any side-effects reported after metamizole use. The treated eyes were randomly assigned eyes in two groups, and each patient had one eye assigned per group. Group A received 1000 mg of metamizole and group B received a placebo pill forty minutes before initiating the treatment. Each patient scored the pain sensation immediately after PRP using Scott’s visual analogue scale (VAS). Statistics were calculated with SPSS version 20.0. The paired Student t test was used to measure the significance between the two groups VAS scores, with significance level adopted of p<0,05.

 

Results

 

The patients referred a significant lower level of pain during PRP when they were submitted to PRP after oral metamizole treatment when compared tothan placebo (p=0.002)and this difference was significant, with a p value of 0,002. The data was expressed in mean, maximum, minimum scores and standard deviation. The mean pain scores for groups A and B were 4,72 ± 1,708 and 5,89 ± 1,967 , respectively. The minimum/maximum scores within groups A and B were 2/8 and 3/8, respectively (Table 1). The patients referred a lower level of pain during PRP when they were submitted oral metamizole treatment than placebo and this difference was significant, with a p value of 0,002. There was no significant difference between gender, age or chronic disease profile.

 

Conclusions

 

The use of 1000 mg of metamizole 40 minutes before PRP significantly reduced the pain associated with the procedure in patients with proliferative diabetic retinopathy. Thus, metamizole is effective in reducing pain during PRP and can be applied before the procedure, specially in patients with no history of drug allergy.

 

 

Table 1: Mean, maximum and minimum VAS scores for groups A and B

 

Keywords: 499 diabetic retinopathy • 578 laser • 700 retinal neovascularization