Comparison of the Melatonin Receptor Agonist Ramelteon and the Non-Benzodiazepine Hypnotic Zolpidem for Nocturia

To examine the efficacy of the melatonin receptor agonist ramelteon for nocturia, it was compared with zolpidem, a conventional non-benzodiazepine hypnotic. A total of 50 patients with nocturia (32 urinations/night) were enrolled. Subjects assigned odd numbers or even numbers were respectively prescribed 8 mg of ramelteon (n = 27; mean age: 75 years) or 5 mg of zolpidem (n = 23; mean age: 73 years) once a day before sleeping for 4 weeks. The daytime and nighttime frequencies of urination, as well as the results of global self-assessment by the patients, were compared between the two groups before and after 4 weeks of treatment. Both ramelteon and zolpidem caused a significant decrease of nocturia to about once per night after 4 weeks. The global self-assessment rating at 4 weeks was “good” or “fair” for more patients in the zolpidem group than in the ramelteon group, while the rating was “excellent” or “no change” for more patients in the ramelteon group. There were no serious adverse events in either group. Ramelteon was safe and effective for nocturia, achieving similar results to zolpidem. However, responders and non-responders to ramelteon were more clearly distinguished. Ramelteon might be effective for patients with sleep disturbance and nocturia because of low melatonin levels. Therefore, as diagnostic therapy for identification of nocturia caused by sleep disturbance and melatonin deficiency, ramelteon should be administered to patients who do not respond to alpha-1 antagonists and/or anticholinergic agents.