From the Guidelines
For a 74-year-old patient taking mirtazapine (Remeron) 15mg for sleep, the next dosing instruction would be to continue at the current 15mg dose taken once daily at bedtime. This is typically the optimal dose for sleep in elderly patients, as the sedative effects of mirtazapine are actually more pronounced at lower doses (7.5-15mg) than at higher doses 1. Increasing the dose beyond 15mg may not improve sleep and could potentially increase side effects like daytime drowsiness, dizziness, and increased appetite. For elderly patients, medication changes should be made cautiously due to age-related changes in metabolism and increased sensitivity to side effects. The patient should take the medication approximately 30-60 minutes before bedtime to maximize its sleep-promoting effects. If sleep difficulties persist after 2-4 weeks at this dose, the patient should consult their healthcare provider for reevaluation rather than adjusting the dose independently. Regular monitoring for side effects such as morning drowsiness, weight gain, or dizziness is important, especially in this age group.
Some key considerations for this patient include:
- Monitoring for side effects: The patient should be regularly monitored for side effects such as morning drowsiness, weight gain, or dizziness, especially given their age and potential increased sensitivity to these effects 1.
- Combining with non-pharmacological therapies: The patient may also benefit from non-pharmacological therapies such as stimulus control, relaxation training, or cognitive behavioral therapy for insomnia (CBT-I) as outlined in the clinical guideline for the evaluation and management of chronic insomnia in adults 1.
- Adjusting based on response: The choice of a specific medication, including mirtazapine, should be based on the patient’s response to the first dose, with considerations for factors such as treatment history, coexisting conditions, specific side effect profile, cost, and pharmacokinetic profile 1.
Given the available evidence, continuing mirtazapine at 15mg once daily at bedtime is the most appropriate next step for this patient, considering both the potential benefits for sleep and the need to minimize side effects in an elderly patient 1.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION Initial Treatment The recommended starting dose for mirtazapine tablets is 15 mg/day, administered in a single dose, preferably in the evening prior to sleep. Mirtazapine has an elimination half-life of approximately 20 to 40 hours; therefore, dose changes should not be made at intervals of less than 1 to 2 weeks in order to allow sufficient time for evaluation of the therapeutic response to a given dose The next dosing instruction for a 74-year-old patient taking mirtazapine (Remeron) 15mg for sleep is to continue taking 15mg in the evening prior to sleep.
- The patient should not change the dose without consulting the prescriber.
- The prescriber should be aware that plasma mirtazapine levels may be increased in elderly patients, compared to levels observed in younger adults. 2
From the Research
Mirtazapine Dosing Instructions
- The recommended initial dosage of mirtazapine is 15 mg once/day at bedtime, with an effective daily dosage range of 15-45 mg 3.
- For a 74-year-old patient taking mirtazapine 15mg for sleep, the next dosing instruction would be to continue taking 15mg once/day at bedtime, as the initial dosage is within the recommended range 3.
- However, if the patient's sleep disturbances persist, the dosage may be increased to 30 mg/day, and if necessary, further increased to 45 mg/day 4.
Considerations for Elderly Patients
- Mirtazapine has been shown to be effective in reducing chronic insomnia symptoms in older adults, with a significant reduction in Insomnia Severity Index scores compared to placebo 5.
- However, elderly patients may be more susceptible to adverse events, such as increased sedation, dry mouth, and weight gain 4, 6.
- Additionally, there have been reports of terrifying nightmares in elderly patients taking mirtazapine, which may be more frequent than previously believed 7.