Subarachnoid hemorrhage in a patient taking phentermine for weight loss

To report the case of an angiography-negative subarachnoid hemorrhage (SAH) in association with increased use of the sympathomimetic phentermine.

A 45-year-old woman taking phentermine for weight loss presented with the "worst headache of her life," as well as nausea and some confusion. Her prior medical history was largely negative for pathology except for a 20-pack-year history of smoking.

Upon admission to an inpatient facility, the patient was normotensive with a Glasgow Coma Score of 15. She was found on computed tomography to have a diffuse SAH (Hunt and Hess grade 2, Fisher grade 3). Digital subtraction angiography, performed on hospital day 2, was negative for aneurysm. The patient convalesced in the intensive care unit for 8 days and was treated as a typical patient with SAH (i.e., vasospasm prophylaxis with nimodipine and atorvastatin, ad lib diet with strict attention to fluid balance to maintain euvolemia). A repeat angiographic study on hospital day 8 also did not reveal an aneurysm or other cause for her SAH. She was discharged thereafter with intensive smoking cessation education and counseled to discontinue phentermine. Upon follow-up 6 weeks later, the patient was without complaints or neurologic deficits and had resumed her previous activities and work.

Phentermine is a sympathomimetic agent found commonly in weight-loss products. Sympathomimetics have been linked to the development of hypertension, which can lead to cardiovascular and neurologic hemorrhages. We believe that the SAH in this patient was likely secondary to drug-induced hypertension or vasculopathy from the phentermine.