CYP2C19 and Vertigo: Patients with CYP2C19*1/*2 genotype experienced nervous system (headache, vertigo) and gastrointestinal disorders (constipation, nausea), CYP2C19*2/*17 patients suffered from gastrointestinal (nausea, vomiting), nervous system (headache, vertigo), skin disorders (erythema, rash), haematuria and elevated GGT values.