<p>The side effects reported include nervousness, agitation, irritability, anxiety and sleep disturbances. The incidence of these during clinical trials was (&le; 5%) and they were more often noted in the older patients taking &gt; 2.4 gm daily. In the majority of cases, a dose reduction sufficed to make these symptoms disappear. Some patients may complain of fatigue or drowsiness, gastrointestinal problems, e.g. nausea, vomiting, diarrhoea and stomachache have also been reported but their incidence during clinical trials was &le; 2%. Other symptoms e.g. vertigo, headache, trembling and sexual stimulation have occasionally been reported.</p>