Risperidone Starting Dose for Patients with Prior Exposure
For adult patients who have previously taken risperidone, start at 2 mg/day (either once daily or divided into two doses), which is the standard initial dose recommended by the FDA for schizophrenia in adults. 1
Rationale for Standard Dosing Despite Prior Use
Prior exposure does not justify skipping the initial titration phase. The FDA label explicitly recommends that "after an interval off risperidone, the initial titration schedule should be followed" when reinitiating treatment. 1
The 2 mg/day starting dose balances efficacy and tolerability. This dose can be administered once daily or divided into twice-daily dosing, with subsequent increases of 1-2 mg/day at intervals of 24 hours or greater as tolerated, targeting 4-8 mg/day for most patients. 1
Titration Strategy
Increase slowly to avoid extrapyramidal symptoms (EPS). Dose increases should be spaced at least 14-21 days apart to minimize EPS risk, particularly if the patient previously experienced side effects. 2
Target the 4-6 mg/day range for optimal response. Current evidence suggests 4 mg/day is the optimal target dose for most patients, with doses above 6 mg/day offering no additional efficacy but significantly increasing EPS risk. 2, 3, 4
Consider split dosing if side effects occurred previously. Dividing the daily dose (e.g., 2 mg at bedtime + 1 mg in morning) reduces peak plasma concentrations and may decrease orthostatic hypotension, drowsiness, and insomnia while maintaining 24-hour coverage. 2
Special Populations Requiring Lower Starting Doses
Elderly Patients
- Start at 0.25-0.5 mg/day at bedtime for elderly patients, particularly those with dementia, with a maximum of 2-3 mg/day divided into two doses. 2, 5
- EPS can occur at doses as low as 2 mg/day in this population. 6, 2
First-Episode Psychosis
- Do not exceed 4 mg/day in first-episode patients, as higher doses provide no additional benefit and increase adverse effects. 2
Renal or Hepatic Impairment
- Start at 0.5 mg twice daily and increase to doses above 1.5 mg twice daily only at intervals of one week or longer. 1
Critical Monitoring Points
Watch for EPS even at therapeutic doses. Risperidone has the highest risk of extrapyramidal symptoms among atypical antipsychotics, with risk markedly increasing above 4 mg/day and further escalating above 6 mg/day. 2
Avoid prophylactic benztropine. Do not routinely prescribe anticholinergic agents when restarting risperidone; use them only if EPS develop or in clearly high-risk situations (young males, rapid titration, doses ≥4 mg/day, prior EPS history). 2
Monitor for orthostatic hypotension, insomnia, agitation, and drowsiness, which are common even at low doses. 6, 2
Common Pitfalls to Avoid
Do not start at the patient's previous maintenance dose. Even if the patient tolerated 6 mg/day previously, restart at 2 mg/day and retitrate to avoid acute side effects. 1
Do not exceed 6 mg/day in routine practice. Doses above this threshold demonstrate no greater efficacy but significantly increase adverse effects, particularly movement disorders. 2, 1, 4
Do not titrate faster than every 24 hours initially, and preferably space increases 14-21 days apart for optimal tolerability. 2, 1