Are palpitations a side effect of buspirone?

Are Palpitations a Side Effect of Buspirone?

Yes, palpitations are a recognized side effect of buspirone, occurring in approximately 1% of patients in controlled clinical trials, though they remain relatively uncommon compared to other adverse effects.

Incidence and Clinical Significance

• Palpitations occur in approximately 1% of buspirone-treated patients according to FDA-approved labeling data from controlled clinical trials 1
• In a meta-analysis comparing dosing regimens, palpitations occurred significantly more frequently with buspirone 15 mg twice daily (5%) compared to 10 mg three times daily (1%), suggesting a potential dose-related effect 2
• This side effect is classified among cardiovascular adverse events but is generally considered a pharmacologic effect rather than a serious adverse reaction 1

Mechanism and Context

• Buspirone stimulates central sympathetic activity, which is reflected in increased peripheral neural sympathetic activity in healthy individuals 3
• The drug significantly increases circulating levels of noradrenaline and dopamine, which can manifest as palpitations through sympathetic nervous system activation 3
• These cardiovascular effects are similar to the transient pharmacologic effects seen with other medications that increase sympathetic tone, such as epinephrine (which commonly causes palpitations as an expected pharmacologic effect) 4

Relative Frequency Compared to Other Side Effects

• Palpitations are much less common than the most frequent buspirone side effects: dizziness (12%), drowsiness (10%), nausea (8%), nervousness (5%), and headache (6%) 1
• The overall adverse event profile of buspirone remains favorable, with only approximately 10% of patients discontinuing treatment due to any adverse event during premarketing trials 1
• Cardiovascular disturbances are not among the primary reasons for drug discontinuation (which are mainly CNS disturbances at 3.4% and GI disturbances at 1.2%) 1

Clinical Management Considerations

• The twice-daily dosing regimen appears to carry higher risk for palpitations than three-times-daily dosing, despite equivalent total daily doses 2
• If palpitations occur, consider redistributing the total daily dose to more frequent, smaller doses (e.g., switching from 15 mg BID to 10 mg TID) 2
• Small but significant drops in systolic blood pressure and heart rate have been observed after buspirone ingestion, which may accompany or counterbalance the palpitation sensation 3
• Unlike psychostimulants (methylphenidate, dextroamphetamine), buspirone does not require avoidance in patients with underlying coronary artery disease or tachyarrhythmias, as it is not contraindicated in these populations 4

Important Caveats

• Palpitations should not be confused with serious cardiac arrhythmias, which are not characteristic of buspirone therapy 1
• The 2-4 week delay in therapeutic anxiolytic effect means that palpitations occurring early in treatment are not offset by anxiety reduction initially 5, 6
• Patients may misattribute anxiety-related palpitations to the medication, so careful assessment of temporal relationship to dosing is important 1