Starting Dose of Buspirone for Mild Anxiety
Start buspirone at 5 mg twice daily (total 10 mg/day), then increase by 5 mg/day every 2–3 days to reach a target of 15–30 mg/day in divided doses. 1, 2
Initial Dosing Protocol
Begin with 5 mg twice daily (morning and evening) for the first 2–3 days to assess tolerability and minimize side effects such as dizziness, headache, and nausea. 1, 2
Titrate upward by 5 mg/day every 2–3 days based on response and tolerability, aiming for a therapeutic range of 15–30 mg/day divided into two or three daily doses. 1, 2, 3
Two equally effective dosing schedules exist: 15 mg twice daily (BID) or 10 mg three times daily (TID)—both achieve similar efficacy and safety, though BID may improve compliance. 1, 4, 5
The maximum dose is 60 mg/day, though this is rarely needed for mild anxiety. 1, 2, 3
Critical Timing Expectations
Buspirone requires 2–4 weeks to become fully effective, making it unsuitable for acute anxiety requiring immediate relief. 1, 2
Counsel the patient at initiation that symptom improvement will be gradual, not immediate, to maintain adherence during the lag period. 1, 2
Assess response at 2–4 weeks, not earlier, to allow adequate time for therapeutic effect before considering dose adjustment or alternative therapy. 2
Quetiapine Interaction Considerations
No specific drug interaction exists between buspirone and quetiapine that would require dose adjustment of buspirone. 3
The patient's prior use of quetiapine 25 mg (now discontinued) does not alter the buspirone starting dose, as quetiapine is no longer active in the system and buspirone does not require washout from other psychotropics (except MAOIs). 3
If the patient were still taking quetiapine, buspirone could be safely initiated at standard doses, as both agents work through different receptor mechanisms (buspirone via 5-HT1A partial agonism; quetiapine via dopamine/serotonin antagonism). 6, 7
Administration Guidelines
Take buspirone consistently with regard to food—either always with meals or always on an empty stomach—because food increases bioavailability approximately 2-fold. 3, 8
Administer the second daily dose earlier in the day (not late evening) to minimize potential insomnia risk. 2
Common Prescribing Pitfalls to Avoid
Do not start at too high a dose (e.g., 15 mg BID immediately), as this increases side effects without faster benefit. 2
Do not discontinue prematurely before 2–4 weeks, as the therapeutic window has not been reached and early discontinuation will appear as treatment failure. 1, 2
Do not use buspirone for severe agitation or acute panic—it is only effective for mild-to-moderate generalized anxiety. 1, 2
Most Common Side Effects
Dizziness, headache, nausea, nervousness, and lightheadedness are the most frequent adverse effects, typically mild and transient. 1, 4, 5
The overall incidence of adverse events is low, and buspirone lacks the sedation, cognitive impairment, and abuse potential associated with benzodiazepines. 6, 7