Large doses or a run of quickly repeated doses over a period of some hours can cause anxiety and panic, which may develop into paranoia and hallucination. Most people will suffer nothing more than a moderate increase in blood pressure and mild heart pounding. But with a very large dose, or a lot of smaller doses, blood pressure and pulse may suddenly rocket and the heart starts skipping beats, which can lead to a collapse or heart attack. The consequences of long-term use, says DrugScope, become unpleasant. That euphoria turns into an uncomfortable restlessness, over-excitability, nausea, insomnia and weight loss.
Some people become anorexic.
Others develop a sort of persecution mania. Confusion and exhaustion due to lack of sleep are not uncommon. All this sorts itself out over a few months if cocaine use is stopped.