Moclobemide (Zorix) Dosage and Usage for Depression and Social Anxiety
For depression, moclobemide should be started at 300 mg/day divided into 2-3 doses, with a typical therapeutic range of 300-600 mg/day. For social anxiety disorder, higher doses of 600-900 mg/day are often required for optimal efficacy. 1, 2
Dosage Guidelines
For Depression:
- Initial dose: 300 mg/day divided into 2-3 doses
- Typical therapeutic range: 300-600 mg/day
- Maximum dose: 600 mg/day
- Administration: Take with food to improve tolerability
For Social Anxiety Disorder:
- Initial dose: 300 mg/day divided into 2-3 doses
- Therapeutic range: 600-900 mg/day (higher doses tend to be more effective)
- Maximum dose: 900 mg/day
- Duration: Long-term treatment may be necessary as studies show high relapse rates (88%) after discontinuation 3, 4
Pharmacokinetics
- Reaches steady-state plasma levels after approximately one week
- After multiple dosing, oral bioavailability approaches 100%
- Short plasma elimination half-life allows switching to alternative agents within 24 hours if needed 2
Monitoring and Titration
- Plasma concentration monitoring is useful in determining optimal dosing
- Target plasma concentration: 216±55 ng/mL at 100 mg three times daily 1
- Titrate dose gradually to minimize side effects
- Assess response after 2-4 weeks at a stable dose
Special Populations
Elderly:
- Particularly suitable for elderly patients due to minimal cognitive, psychomotor, and cardiovascular effects 2
- Start at lower doses and titrate more slowly
Renal Impairment:
- No dose adjustment required in renal dysfunction 2
Hepatic Impairment:
- Dose reduction necessary in severe hepatic impairment 2
Side Effects and Management
Common Side Effects:
- Insomnia (11.2%)
- Dizziness (4.5%)
- Dry mouth (3.7%)
- Nausea
- Headache 5
Management of Side Effects:
- Take with food to reduce gastrointestinal effects
- Divide daily dose to minimize insomnia
- Most side effects are mild and occur mainly in the first 2 months of treatment 3
Drug Interactions and Precautions
Major Precautions:
- Avoid combining with other serotonergic medications due to risk of serotonin syndrome 1
- Do not combine with MAOIs including other MAOIs, phenelzine, isocarboxazid, isoniazid, and linezolid 1
- Exercise caution when combining with:
Dietary Considerations:
- Unlike irreversible MAOIs, strict dietary restrictions are not required at standard doses
- However, at doses above 900 mg/day, tyramine-rich food interactions may become clinically relevant 2
Efficacy Considerations
- Moclobemide is as effective as tricyclic antidepressants and SSRIs for depression 2
- For social anxiety, higher doses (600-900 mg/day) tend to show better efficacy 6, 4
- Long-term treatment may be necessary, particularly for social anxiety disorder, as studies show high relapse rates after discontinuation 3, 4
Treatment Duration
- For depression: Minimum 6 months after symptom resolution
- For social anxiety: Long-term treatment often required, with studies showing benefit from continuous treatment for up to 2 years 3, 4
Discontinuation
- Taper gradually to minimize discontinuation symptoms
- Monitor closely for relapse, especially in social anxiety disorder where relapse rates of 88% have been observed after discontinuation 4