DELIRIUM FREQUENTLY AFFECTS old patients, and often causes poor prognosis of their physical disorders. First- and second-generation antipsychotic drugs are often prescribed to treat delirium but they have serious adverse effects such as oversedation and QT prolongation. Ramelteon, which is a melatonin receptor agonist with a high affinity for MT1 and MT2 receptors, and is a sleep-promoting drug that stabilizes circadian rhythms, has few adverse effects. Only two case series of delirium patients treated by ramelteon have been published.[3, 4] There are few reports, however, of the usefulness of ramelteon in patients with delirium who are intolerant of antipsychotics. We report successfully treated delirium in such an extremely elderly patient by switching from risperidone to ramelteon. Consent for publishing this letter was obtained from the patient and his son.
A 100-year-old Japanese man was admitted to the intensive care unit (ICU) with severe pneumonia. He had a surgical history of prostate cancer, an implantable pacemaker for complete atrioventricular block, and no history of neuropsychiatric problems or dementia. On the fifth day the patient's condition had improved after intensive treatment with antibiotics. Percutaneous oxygen saturation had improved from 50% to 94% in room air. C-reactive protein level had decreased from 12.8 mg/dL to 6.5 mg/dL. After moving to a general ward from the ICU, he had disorientation, agitation, delusion, and sleep disturbance excitement and aggressiveness. He often said ‘I am in a jail’ and ‘Open the door’, and also threatened and beat medical staff. It was difficult to obtain cooperation for treatment. He was diagnosed as having delirium. After single use of risperidone 0.5 mg at 18.00 hours on the sixth day, he showed oversedation all day for 2 days. On the ninth day, although the patient's health had improved and C-reactive protein level had decreased to 3.1 mg/dL, he had severe psychomotor excitement again. Ramelteon 8 mg at 21.00 hours daily was started. The delirium improved without any adverse effects, including oversedation. On the 13th day, Delirium Rating Scale–Revised 98 (DRS-R-98) score was reduced from 41 just before ramelteon to 10. On the 39th day, when he was discharged, this score had improved to 6.
The exact mechanism of action of ramelteon for delirium is still unclear. Although this patient's delirium might have improved spontaneously, the findings suggest that ramelteon is a useful and safe alternative for the treatment of delirium in extremely elderly patients.