What is the recommended dosage of quetiapine (Seroquel) for treating depression and anxiety?

Quetiapine Dosage for Depression and Anxiety

For depression and anxiety, quetiapine should be initiated at 50 mg once daily at bedtime, gradually titrated to 150-300 mg/day, with 300 mg/day being the maximum recommended dose for depression. 1

Dosing Guidelines

For Depression:

• Starting dose: 50 mg once daily at bedtime
• Day 2: 100 mg at bedtime
• Day 3: 200 mg at bedtime
• Day 4: 300 mg at bedtime (target dose)
• Maximum dose: 300 mg/day 1

For Anxiety (off-label use):

• Starting dose: 25-50 mg at bedtime
• Titration: Increase by 50 mg increments every 3-7 days based on response and tolerability
• Effective dose range: 50-300 mg/day
• Maximum dose: 300 mg/day 2

Evidence-Based Efficacy

Quetiapine has demonstrated efficacy for both depression and anxiety in clinical trials:

• For bipolar depression, quetiapine 300 mg/day and 600 mg/day were equally effective in improving depressive symptoms 3, 4
• In treatment-resistant depression, quetiapine augmentation (mean dose 315 mg/day) significantly reduced depression scores after 4-5 weeks of treatment 5
• For comorbid depression and anxiety, quetiapine XR 150-300 mg/day showed significant improvement compared to placebo 2, 6

Special Populations

Elderly Patients:

• Start at 50 mg/day
• Increase in increments of 50 mg/day based on clinical response and tolerability
• Use slower titration and lower target doses 1

Hepatically Impaired Patients:

• Start at 25 mg/day
• Increase in increments of 25-50 mg/day based on clinical response and tolerability 1

Important Considerations

1. Administration: Can be taken with or without food 1

2. Monitoring: Regular assessment for:

   • Sedation and somnolence (most common side effects)
   • Metabolic changes (weight gain, blood glucose, lipids)
   • Extrapyramidal symptoms
   • Orthostatic hypotension

3. Drug Interactions:

   • Reduce dose to one-sixth when co-administered with potent CYP3A4 inhibitors
   • Increase dose up to 5-fold when used with potent CYP3A4 inducers 1

4. Discontinuation: When stopping treatment after more than one week, gradual tapering is recommended to minimize withdrawal symptoms 1

Common Side Effects

• Dry mouth
• Sedation/somnolence
• Dizziness
• Constipation
• Increased appetite
• Weight gain

Clinical Pearl

While quetiapine is FDA-approved for bipolar depression, its use for unipolar depression and anxiety disorders is off-label. However, clinical evidence supports its efficacy in these conditions, particularly when used as augmentation to first-line antidepressants or as monotherapy in treatment-resistant cases 2, 5, 6.