Qsymia and Liver disease

In general, CNS stimulants are extensively metabolized by the liver. Their plasma clearance may be decreased and their half-life prolonged in patients with impaired hepatic function. Therapy with CNS stimulants should be administered cautiously in patients with moderate to severe liver disease, and the dosage should be adjusted accordingly. Additionally, postmarketing reports have shown that atomoxetine can cause severe liver injury. Laboratory testing should be done at the first sign or symptom of liver dysfunction (jaundice, dark urine, upper quadrant tenderness) and treatment should be discontinued in patients with evidence of liver injury.

Phentermine may be partially metabolized in the liver. Following administration of a single 15 mg-92 mg dose of phentermine-topiramate, mean phentermine systemic exposure (AUC) was 37% and 60% higher in patients with mild (Child-Pugh score 5 to 6) and moderate (Child-Pugh score 7 to 9) hepatic impairment, respectively, compared to healthy volunteers. No dosage adjustment is necessary in patients with mild hepatic impairment. In patients with moderate hepatic impairment, a reduction in the starting and/or maintenance dosage may be necessary in accordance with the individual product package labeling. Phentermine pharmacokinetics have not been studied in patients with severe hepatic impairment (Child-Pugh score 10 to 15); therefore, use should be avoided.