Severe hypertriglyceridaemia and hypercholesterolaemia associated with tamoxifen use.

A patient who was given tamoxifen as adjuvant treatment for breast cancer developed very severe hypertriglyceridaemia, hypercholesterolaemia and acute pancreatitis after being treated for 4 months. The hyperlipidaemia was corrected after cessation of the tamoxifen and the institution of gemfibrozil treatment. This patient appears to have type IV hyperlipidaemia. It is suggested that, in such patients, tamoxifen should be used with extreme caution because the weakly oestrogenic effect of this agent can cause severe and life threatening hyperlipidaemia.