From the Guidelines
Mirtazapine 7.5 mg can cause several adverse effects, including sedation, drowsiness, weight gain, and increased appetite, which are particularly pronounced at this lower dose due to mirtazapine's strong antihistamine effects at lower doses. Common side effects also include dry mouth, constipation, and dizziness, which may occur due to the drug's anticholinergic properties 1. Some patients experience morning grogginess or a "hangover" effect because of the medication's long half-life. Less commonly, mirtazapine can cause abnormal dreams, confusion, or peripheral edema. Rare but serious side effects include agranulocytosis (severe reduction in white blood cells), serotonin syndrome (especially when combined with other serotonergic medications), and suicidal thoughts, particularly when starting treatment or changing doses 1.
Adverse Effects
- Sedation and drowsiness
- Weight gain and increased appetite
- Dry mouth, constipation, and dizziness
- Morning grogginess or "hangover" effect
- Abnormal dreams, confusion, or peripheral edema
- Agranulocytosis, serotonin syndrome, and suicidal thoughts (rare but serious)
Management
Taking mirtazapine at bedtime rather than during the day can help manage the sedation. Patients should avoid alcohol while taking this medication as it can dangerously increase sedation effects. The sedative effects typically diminish somewhat with continued use as tolerance develops, but may persist throughout treatment 1.
Key Considerations
- Monitor for hepatotoxicity when using mirtazapine, especially in combination with other medications 1.
- Be aware of the potential for increased risk of nonfatal suicide attempts with selective serotonin reuptake inhibitors (SSRIs) 1.
- Mirtazapine had a faster onset of action than fluoxetine, paroxetine, or sertraline, but the evidence base was limited 1.
From the FDA Drug Label
Mirtazapine tablets may cause serious side effects, including: • Low white blood cell count. • Serotonin syndrome • Eye problems (angle-closure glaucoma). • Heart rhythm problems. • Severe skin reaction • Increased appetite and weight gain. • Sleepiness. • Mania or hypomania (manic episodes) in people who have a history of bipolar disorder. • Seizures (convulsions). • Increased fat levels (cholesterol and triglycerides) in your blood • Low sodium levels in your blood (hyponatremia). The most common side effects of mirtazapine tablets include: • sleepiness • increased appetite • weight gain • dizziness
Common adverse effects of Mirtazapine 7.5 include:
- Sleepiness
- Increased appetite
- Weight gain
- Dizziness Serious adverse effects may include:
- Low white blood cell count
- Serotonin syndrome
- Eye problems (angle-closure glaucoma)
- Heart rhythm problems
- Severe skin reaction
- Mania or hypomania (manic episodes) in people with a history of bipolar disorder
- Seizures (convulsions)
- Increased fat levels (cholesterol and triglycerides) in the blood
- Low sodium levels in the blood (hyponatremia) 2
From the Research
Adverse Effects of Mirtazapine 7.5mg
- The most commonly reported adverse events associated with mirtazapine are transient somnolence, hyperphagia, and weight gain, which may be attributed to the antihistaminic (H1) activity of mirtazapine at low doses 3.
- At a dose of 7.5mg, mirtazapine was well tolerated, and no clinically significant adverse effects, primarily drowsiness or increased appetite, were reported 4.
- Common adverse effects of mirtazapine include dry mouth, sedation, and increases in appetite and body weight 5.
- Mirtazapine has a unique tolerability profile, with a low incidence of anticholinergic, adrenergic, and serotonergic-related adverse events compared to tricyclic antidepressants 6.
- Mirtazapine is not associated with sexual dysfunction, which is a common side effect of selective serotonin reuptake inhibitors (SSRIs) 5.
Comparison of Adverse Effects with Other Antidepressants
- Mirtazapine appears to be better tolerated than amitriptyline, with significantly fewer patients experiencing anticholinergic, cardiac, and neurological adverse events 6.
- Mirtazapine is at least as well tolerated as clomipramine, doxepin, and trazodone in comparative trials, with slightly lower incidences of anticholinergic and neurological adverse events 6.
- Mirtazapine has a lower propensity for inducing seizures compared to other antidepressants 6.