In this patient, continuation of gliclazide despite blurred vision shortly after initiation can be cautiously considered if the symptom is suspected to result from osmotic changes due to rapid glucose lowering, a known transient phenomenon when blood glucose improves. However, close monitoring is essential to distinguish osmotic effects from more serious adverse effects such as hypoglycaemia or sulfonylurea-induced retinal changes, especially due to her multiple comorbidities and use of warfarin.
Immediate steps should include assessing blood glucose frequently and reviewing for hypoglycaemic episodes or other ocular pathology. If blurred vision persists beyond a few days, worsens, or is accompanied by hypoglycaemic symptoms or other complications, discontinuation of gliclazide should be strongly considered until the cause is clarified.
Furthermore, given her poor surgical candidacy and unstable INR, it is prudent to avoid insulin if refused, but also to carefully balance glucose-lowering regimens to minimize hypoglycaemia risk from sulfonylureas like gliclazide, adhering to stepwise therapy and shared decision-making as per guidelines.