Chloroquine and hydroxychloroquine
Both chloroquines have reported infrequent Gl adverse effects (ie, nausea, vomiting, abdominal pain, and diarrhea).84 , 85 The National Institute of Health LiverTox resource rates both drugs with a likelihood score of D (possible rare cause of clinically apparent liver injury).86 Chloroquine is rarely linked to aminotransferase elevations or clinically apparent liver injury. In patients with acute intermittent porphyria or porphyria cutanea tarda, it can trigger a hypersensitivity attack with fever and serum aminotransferase elevations, sometimes resulting in jaundice. This is seen less commonly with hydroxychloroquine. Such reactions are thought to be hypersensitivity reactions and there is no known cross-reactivity in liver injury between hydroxychloroquine and choloroquine. Hydroxychloroquine is known to concentrate in the liver, thus patients with hepatitis or other hepatic diseases, or patients taking other known hepatotoxic drugs, should exercise caution. In addition, cardiac conduction defects leading to clinically relevant arrhythmias are an important adverse effect of these medications.