Letters to the Editor
Suspected Propranolol-Induced Delirium
Dear Editor:
Propranolol has been used for many years in internal medicine, neurology, and psychiatry. Surprisingly, only a few case reports of propranolol-induced delirium have been published to date, according to Medline and Toxline databases. In 1979, Kuhr reported a case of prolonged delirium with propanolol use (1). Two cases of delirium, the first associated with combined propranolol and maprotiline and the second associated with combined propranolol, benztropine, and fluphenazine decanoate, have also been described (2,3). In 1994, Chen reported 3 cases of elderly patients with recent cerebral infarction and preexisting brain dysfunction who were receiving 30 to 60 mg of propranolol daily (4). Watanabe found adjunctive propranolol, scopolamine, and (or) flurazepam before or after surgery to be the strongest predictor of delirium in postoperative orthopedic patients (5). It remains uncertain whether propranolol-induced delirium is very rare or just not reported.
Case Report
A man aged 74 years, a retired joiner, was first admitted to the psychogeriatric unit owing to increasing aggressiveness that was first noticed 3 years earlier. Family members reported paranoid delusions. On admission, he was oriented in time and place. His Mini-Mental State Examination (MMSE) score was 21. Blood counts, bilirubin, aspartate transaminase, alanine aminotransferase, alkaline phosphatase, albumin, potassium, sodium, calcium, glucose, creatinine, urea, and thyroid hormones were within normal limits. ECG revealed sinus arrhythmia. Because he suffered from prostatic carcinoma, the patient had been treated with ciproterone 200 mg daily for 4 years. Olanzapine 5 mg daily was started for treatment of his paranoid delusions. Propranolol had been suggested earlier by a neurologist to alleviate essential tremor, but the patient never started this treatment. On the fifth day after admission, propranolol was started at 40 mg daily and gradually increased to 120 mg daily, when delirium was noticed at night. The patient became sleepless, restless, and disoriented and showed impaired consciousness. During the day, he was tired but without impaired consciousness. On the third day, propranolol was discontinued. Symptoms of delirium disappeared the next day. A decrease in diastolic blood pressure of only 10 mm Hg was measured during the treatment with propranolol.
It is well known that delirium is more often a consequence of multiple etiologic factors than a consequence of a single one. Delirium may be attributed to central beta blockade; in our case, however, preexisting cognitive decline, old age, and other physical illnesses may have predisposed the patient to propranolol toxicity. That said, the time of beginning and resolving the delirium strongly suggest propranolol as the main etiologic factor. The patients tremor was later successfully alleviated with gabapentin.
References
1. Kuhr BM. Prolonged delirium with propanolol. J Clin Psychiatry 1979;40:1989.
2. Saiz-Ruiz J, Moral L. Delirium induced by association of propranolol and maprotiline. J Clin Psychopharmacol 1988;8(1):778.
3. Lima BR, Vanneman D. Propranolol, benztropine, fluphenazine decanoate, and delirium. Am J Psychiatry 1983;140:65960.
4. Chen WH, Liu JS, Chang YY. Low dose propranolol-induced delirium: 3 cases report and a review of literature. Gaoxiong Yi Xue Ke Xue Za Zhi 1994;10(1):407.
5. Watanabe JC. Drug-induced delirium in elderly postoperative hip surgery patients [abstract]. Presented at ASHP Midyear Clinical Meeting; 1991 Dec 12; New Orleans (LA).
Ales Kogoj, MD
Ljubljana Polje, Slovenia
|
