Can atenolol, Buspar (buspirone), mirtazapine, and gabapentin be taken as needed (prn) for anxiety?

Using Atenolol, Buspirone, Mirtazapine, and Gabapentin PRN for Anxiety

None of these medications should be used "as needed" (PRN) for anxiety—they require scheduled dosing to be effective, and PRN use is not supported by evidence or FDA labeling. 1

Why PRN Dosing Fails for These Agents

Buspirone (BuSpar)

• Requires 2-4 weeks of continuous daily dosing to become effective for anxiety symptoms 2
• FDA-approved for generalized anxiety disorder but only with scheduled administration, not PRN use 1
• Acts on 5-HT1A serotonin receptors through a mechanism that requires steady-state levels to produce anxiolytic effects 3
• Indicated for short-term relief of anxiety symptoms or management of anxiety disorders, but effectiveness requires continuous use 1
• Dosing schedule: Start 5 mg twice daily, maximum 20 mg three times daily 2

Mirtazapine (Remeron)

• Antidepressant requiring 4-8 weeks for full therapeutic effect on anxiety symptoms 2
• Must be dosed daily (typically at bedtime) to maintain therapeutic blood levels 2
• PRN use provides no anxiolytic benefit and only causes sedation without addressing underlying anxiety 2
• Dosing schedule: Start 7.5 mg at bedtime, maximum 30 mg at bedtime 2

Gabapentin

• Not FDA-approved for anxiety disorders and carries significant risks when used long-term 4
• Gabapentin dependence and withdrawal syndromes occur with chronic use, similar to benzodiazepines 5
• When combined with other CNS depressants (like mirtazapine), dangerous respiratory depression can occur 4
• Listed only as second-line for social anxiety disorder in Canadian guidelines, requiring scheduled dosing 4
• Case reports document delirium, intense cravings, and prolonged withdrawal confusion when gabapentin is abused or discontinued 5

Atenolol

• Limited evidence exists for atenolol in anxiety disorders 2
• One preliminary military study showed 86% of patients reported positive effects, but this was not placebo-controlled or blinded 6
• The study involved scheduled daily dosing, not PRN use 6
• Beta-blockers like atenolol may help with physical symptoms of anxiety (tremor, palpitations) but do not address core anxiety pathology 7

Evidence-Based Alternatives for Anxiety

First-Line Pharmacotherapy

• SSRIs (paroxetine, sertraline) or SNRIs (venlafaxine XR) are first-line treatments with substantial efficacy evidence 4, 8
• These require 4-8 weeks of daily dosing to achieve therapeutic effect 2, 8
• Remission rates approach 40% with appropriate first-line therapy 8

Short-Term PRN Options (When Truly Needed)

• Benzodiazepines (lorazepam, oxazepam) are the only medications appropriate for PRN anxiety management 2
• Use infrequent, low doses of short half-life agents to minimize tolerance and dependence 2
• Limit to short-term management of severe anxiety only—not recommended for long-term use due to dependence risks 4, 8
• Approximately 10% of patients experience paradoxical agitation with benzodiazepines 2

Non-Pharmacologic First-Line Treatment

• Cognitive behavioral therapy (CBT) is recommended as first-line treatment alongside or instead of medication 4

Critical Safety Concerns with This Combination

Combining gabapentin with mirtazapine creates excessive sedation risk and potential respiratory depression 4. The proposed regimen mixes:

• Two sedating agents (mirtazapine, gabapentin)
• One agent with dependence potential similar to benzodiazepines (gabapentin) 5
• One agent requiring weeks to work (buspirone) 2
• One agent with minimal anxiety evidence (atenolol) 6

This polypharmacy approach lacks evidence and increases adverse effect burden without providing effective PRN anxiety relief.

Recommended Approach

Start a single SSRI or SNRI as scheduled daily therapy for generalized anxiety disorder 4, 8. If breakthrough anxiety occurs during the 4-8 week onset period, consider short-term scheduled benzodiazepine use (not PRN) that is tapered as the antidepressant takes effect 8. Buspirone can be added as scheduled therapy if first-line agents fail or are contraindicated 8. Avoid gabapentin for anxiety given dependence risks and lack of FDA approval for this indication 4, 5.