What is the recommended initial dose for a second-generation antipsychotic (SGA)?

Initial Dosing for Second Generation Antipsychotics

The recommended initial dose for a second-generation antipsychotic should be low, with risperidone starting at 0.25-2 mg/day, olanzapine at 2.5-5 mg/day, or quetiapine at 12.5-25 mg twice daily, and then gradually titrated based on response and tolerability. 1

Initial Dosing Guidelines by Medication

Atypical Antipsychotics for Adults

• Risperidone: Start with 0.25-2 mg/day (at bedtime), maximum 2-3 mg/day in divided doses 1
• Olanzapine: Start with 2.5 mg/day (at bedtime), maximum 10 mg/day in divided doses 1, 2
• Quetiapine: Start with 12.5 mg twice daily, maximum 200 mg twice daily 1
• Aripiprazole: Start with 10 mg/day 3
• Asenapine: Start with 10 mg/day 3
• Lurasidone: Start with 40 mg/day 3
• Paliperidone: Start with 3 mg/day 3

For First-Episode Psychosis

• Risperidone: 2 mg/day 1
• Olanzapine: 7.5-10 mg/day 1
• Lower doses are particularly important in first-episode patients to minimize side effects and improve adherence 1

Dosing Considerations

Age-Related Considerations

• Geriatric patients should receive even lower starting doses 4:
  • Risperidone: 0.25 mg/day
  • Olanzapine: 2.5 mg/day
  • Quetiapine: 12.5 mg twice daily 1

Titration Approach

• After initial dosing, increase doses gradually (typically every 5-7 days) until therapeutic benefit or side effects appear 1
• For first-episode psychosis, assess response frequently but increase doses only at widely spaced intervals (14-21 days after initial titration) 1
• Allow at least 4 weeks at therapeutic dose to determine efficacy before switching medications 1

Monitoring for Side Effects

• Prioritize avoiding extrapyramidal symptoms (EPS), especially in first-episode patients 1
• Monitor for metabolic effects, particularly with olanzapine 2
• For olanzapine, consider concurrent metformin to attenuate weight gain 1
• For quetiapine, be aware of potential sedation and orthostatic hypotension 1

Common Pitfalls to Avoid

• Starting with too high a dose: This increases risk of side effects and reduces adherence 1
• Increasing doses too quickly: Allow sufficient time (2-4 weeks) to assess response before increasing 1
• Ignoring physical comorbidities: For patients with diabetes, obesity, or dyslipidemia, avoid olanzapine and clozapine 4
• Overlooking drug interactions: Be cautious when combining antipsychotics with other medications that affect the same metabolic pathways 4
• Inadequate duration of trial: If switching medications due to inadequate response, ensure a full 4-week trial at therapeutic dose was completed 1

Treatment Algorithm

1. Start with low dose of selected antipsychotic based on side effect profile and patient characteristics 1
2. Titrate slowly over 2-4 weeks to reach target therapeutic dose 1
3. Evaluate response after 4 weeks at therapeutic dose 1
4. If inadequate response with good adherence, consider switching to a different antipsychotic with a different pharmacodynamic profile 1
5. If two adequate trials fail, consider clozapine or specialist referral 1

Remember that second-generation antipsychotics have a lower risk of extrapyramidal symptoms compared to first-generation agents, but they still require careful dosing and monitoring for optimal outcomes 1.