Pregnancy Category C
Tramadol has been shown to be embryotoxic and fetotoxic in mice, (120 mg/kg or 360 mg/m2), rats (≥25
mg/kg or 150
mg/m2) and rabbits (≥75
mg/kg or 900
mg/m2) at maternally toxic dosages, but was not teratogenic at these dose levels. These dosages on a mg/m2 basis are 1.4, ≥0.6, and ≥3.6 times the maximum daily human dosage (246 mg/m2) for mouse, rat and rabbit, respectively.