[Drug-induced pneumonitis in a patient treated with venlafaxine and propanolol]

Venlafaxine and propranolol have rarely been identified as causes of pulmonary pathology. We describe a case of drug-induced pneumonitis occurring in a patient treated with these two medications.

A 55 years old woman with liver cirrhosis treated with venlafaxine for 1 year and propranolol for 1 month was admitted to the intensive care unit because of acute respiratory failure. A Mycoplasma pneumoniae pneumonitis was diagnosed. After initial improvement under antibiotics, a new deterioration of respiratory status was observed 4 days after the reintroduction of venlafaxine and propranolol. Spontaneous recovery occurred after these treatments were withheld. Co administration of venlafaxine and propranolol, 2 drugs with affinity for the same cytochrome P450 isoenzyme (CYP2D6), may have contributed to drug accumulation and pulmonary toxicity. The liver cirrhosis of our patient may also have contributed to decreased cytochrome P450 enzymatic activity.

Venlafaxine and propranolol share the same metabolic pathway and their co-administration may be complicated by drug induced pneumonitis.