Your doctor should have discussed possible side effects. however, I got this from the interwebs: https://www.medicines.org.uk/emc/medicine/22794
4.8 Undesirable effects
Based on the experience with gliclazide, the following undesirable effects have been reported.
Hypoglycaemia
As for other sulphonylureas, treatment with gliclazide 40mg tablets can cause hypoglycaemia, if mealtimes are irregular and, in particular, if meals are skipped. Possible symptoms of hypoglycaemia are: headache, intense hunger, nausea, vomiting, lassitude, sleep disorders, agitation, aggression, poor concentration, reduced awareness and slowed reactions, depression, confusion, visual and speech disorders, aphasia, tremor, paresis, sensory disorders, dizziness, feeling of powerlessness, loss of self-control, delirium, convulsions, shallow respiration, bradycardia, drowsiness and loss of consciousness, possibly resulting in coma and lethal outcome.
In addition, signs of adrenergic counter-regulation may be observed: sweating, clammy skin, anxiety, tachycardia, hypertension, palpitations, angina pectoris and cardiac arrhythmia.
Usually, symptoms disappear after intake of carbohydrates (sugar). However, artificial sweeteners have no effect. Experience with other sulphonylureas shows that hypoglycaemia can recur even when measures prove effective initially.
If a hypoglycaemic episode is severe or prolonged, and even if it is temporarily controlled by intake of sugar, immediate medical treatment or even hospitalisation is required.
Gastrointestinal disturbances, including abdominal pain, nausea, vomiting dyspepsia, diarrhoea, and constipation have been reported: if these should occur they can be avoided or minimised if gliclazide is taken with breakfast/meal.
Hypersensitivity reactions can occur, usually in the first 6-8 weeks of therapy, and they consist mainly of allergic skin reactions including pruritis, erythema and bullous eruption.
The following undesirable effects have been more rarely reported:
Skin and subcutaneous tissue disorders: rash, pruritus, urticaria, angioedema, erythema, maculopapular rashes, bullous reactions (such as Stevens-Johnson syndrome and toxic epidermal necrolysis), photosensitivity skin reactions.
Blood and lymphatic system disorders: Changes in haematology are rare. They may include anaemia, leucopenia, thrombocytopenia, agranulocytosis, pancytopenia, haemolytic anaemia, aplastic anaemia and granulocytopenia have been observed during treatment with gliclazide but are not known to be directly attributable to the drug. These are in general reversible upon discontinuation of medication.
Hepato-biliary disorders: raised hepatic enzyme levels (AST, ALT, alkaline phosphatase), hepatitis (isolated reports). Discontinue treatment if cholestatic jaundice appears.
These symptoms usually disappear after discontinuation of treatment.
Eye disorders:
Transient visual disturbances may occur especially on initiation of treatment, due to changes in blood glucose levels.
Class attribution effects:
Cases of erythrocytopenia, agranulocytosis, haemolytic anaemia, pancytopenia and allergic vasculitis, hyponatraemia have been described for other sulphonylureas.
With other sulphonylureas cases were also observed of elevated liver enzyme levels and even impairment of liver function (e.g. with cholestasis and jaundice) and hepatitis which regressed after withdrawal of the sulphonylurea or led to life-threatening liver failure in isolated cases.
