From the Guidelines
Mirtazapine should not be given in the morning as it is typically prescribed at bedtime to promote sleep, appetite, and weight gain. According to the guidelines for managing Alzheimer's disease, mirtazapine is recommended to be taken at bedtime, with an initial dosage of 7.5 mg and a maximum dosage of 30 mg 1. This is because mirtazapine has potent sedating effects, particularly at lower doses, due to its antihistamine activity. However, in some cases, morning administration may be considered for patients who experience excessive daytime sedation or "hangover" effects when taking it at night.
- Key points to consider when deciding on morning dosing include:
- Excessive daytime sedation or "hangover" effects at higher doses
- Paradoxical activation or insomnia with nighttime administration
- Individualized decision-making in consultation with a healthcare provider
- Potential daytime sedation with morning dosing, and caution against driving or operating machinery It's essential to weigh the potential benefits and risks of morning dosing and to prioritize the patient's safety and well-being, considering the potential impact on their morbidity, mortality, and quality of life. The decision to switch to morning dosing should be made with caution and careful consideration of the patient's specific needs and circumstances, as supported by the guidelines 1.
From the FDA Drug Label
The recommended starting dose of mirtazapine tablets is 15 mg once daily, administered orally, preferably in the evening prior to sleep. Take mirtazapine tablets 1 time each day, preferably in the evening at bedtime
The FDA drug label does not provide an indication for mirtazapine to be given in the morning. The recommended administration time is in the evening, prior to sleep or at bedtime 2, 3.
From the Research
Mirtazapine Administration Timing
- The studies provided do not explicitly discuss the indication for mirtazapine to be given in the morning 4, 5, 6, 7, 8.
- However, it is noted that mirtazapine is typically administered at bedtime due to its sedative effects 6, 8.
- One study compared the effects of mirtazapine on alertness and sleep when administered at bedtime in a fixed regimen of 30 mg versus an ascending dose regimen, and found that both regimens facilitated sleep without reducing daytime alertness 6.
- The mean elimination half-life of mirtazapine is approximately 22 hours, making it suitable for once-daily administration, but the timing of administration is not specified 4.
Sleep-Promoting Effects
- Mirtazapine has been shown to have sleep-promoting effects, with improvements in sleep efficiency, total sleep time, and sleep quality 6, 8.
- The sleep-promoting effects of mirtazapine are thought to be due to its ability to increase the release of serotonin and norepinephrine, which can help regulate sleep-wake cycles 5, 8.
- However, mirtazapine can also cause sedation-related side effects, which must be balanced with its sleep-promoting effects 8.
Clinical Use
- Mirtazapine is a noradrenergic and specific serotonergic antidepressant that has been shown to be effective in the treatment of major depressive disorder 4, 5, 7.
- It has a unique pharmacologic profile and favorable pharmacokinetics, with a low propensity for inducing seizures and a low potential for causing anticholinergic, adrenolytic, and serotonin-related side effects 4, 5, 7.