<p>Low blood sugar (hypoglycaemia) is a very common side effect. It may affect more than 1 in 10 people.<br />
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Signs of low blood sugar: Cold sweat; cool pale skin; headache; rapid heartbeat; feeling sick; feeling very hungry; temporary changes in vision; drowsiness; unusual tiredness and weakness; nervousness or tremor; feeling anxious; feeling confused; difficulty in concentrating.</p>