What medications can be used PRN (as needed) for anxiety or insomnia in a general adult population without specified comorbidities or previous substance abuse?

PRN Medications for Anxiety and Insomnia

For acute anxiety, benzodiazepines such as lorazepam 0.5-1 mg PRN remain the most effective option for immediate symptom relief, though they should be limited to short-term use (typically 3-4 weeks) while initiating longer-term treatments. 1, 2, 3

PRN Options for Acute Anxiety

First-Line PRN Agents

• Lorazepam 0.5-1 mg PRN is effective for acute anxiety episodes, with the ability to be administered orally or sublingually for rapid onset 1
• Lower doses (0.25-0.5 mg) should be used in older or frail patients, or those with COPD 1
• Benzodiazepines provide rapid anxiolytic effects within 30-60 minutes, making them suitable for PRN use during acute anxiety episodes 2, 3

Critical Limitations and Warnings

• Benzodiazepines carry significant risks including dependence, withdrawal reactions, cognitive impairment, falls, and daytime sedation, particularly in older adults 4
• Use should be limited to 3-4 weeks maximum while initiating first-line SSRI/SNRI therapy, then tapered over one week 2
• Avoid in patients with severe pulmonary insufficiency, severe liver disease, or myasthenia gravis 1
• May cause paradoxical agitation, delirium, and increased fall risk, especially when combined with antipsychotics 1

Transition Strategy

• Benzodiazepines should be used only during the acute phase (first 3-4 weeks) in combination with an SSRI or SNRI 2
• Once antidepressants become effective (typically 3-4 weeks), benzodiazepine dose should be tapered over one week 2
• SSRIs and SNRIs are considered first-line therapy for ongoing anxiety management due to favorable side effect profiles compared to tricyclic antidepressants 2, 3

PRN Options for Insomnia

Evidence-Based PRN Hypnotics

Short-acting benzodiazepine receptor agonists (BzRAs) are recommended as first-line PRN medications for insomnia, with specific agents selected based on sleep pattern 1, 4

For Sleep-Onset Insomnia (Difficulty Falling Asleep)

• Zaleplon 10 mg (5 mg in elderly) - ultra-short half-life allows middle-of-night dosing if ≥4 hours remain before waking 1, 4
• Zolpidem 10 mg (5 mg in elderly/women) - effective for sleep onset with moderate duration 1, 4
• Ramelteon 8 mg - melatonin receptor agonist with zero addiction potential, particularly suitable for patients with substance use history 4

For Sleep-Maintenance Insomnia (Difficulty Staying Asleep)

• Eszopiclone 2-3 mg - addresses both sleep onset and maintenance 1, 4
• Zolpidem 10 mg (5 mg in elderly/women) - effective for both onset and maintenance 1, 4
• Low-dose doxepin 3-6 mg - specifically effective for sleep maintenance with minimal next-day effects 4

Critical Safety Considerations

• All hypnotics should be supplemented with Cognitive Behavioral Therapy for Insomnia (CBT-I) when possible, as CBT-I demonstrates superior long-term efficacy 1, 4
• Use the lowest effective dose for the shortest duration possible 1, 4
• Patients must have at least 7-8 hours available for sleep before taking medication 4
• Screen for complex sleep behaviors (sleep-driving, sleep-walking) and discontinue immediately if observed 4

Medications to AVOID for PRN Use

• Over-the-counter antihistamines (diphenhydramine, doxylamine) - not recommended due to lack of efficacy data, anticholinergic effects, and tolerance after 3-4 days 1, 4
• Herbal supplements (valerian, melatonin) - insufficient evidence of efficacy 1, 4
• Trazodone - explicitly not recommended for insomnia by the American Academy of Sleep Medicine 4
• Antipsychotics (quetiapine, olanzapine) - only suitable for patients with comorbid conditions requiring these medications, not for primary insomnia 1, 4
• Barbiturates and chloral hydrate - not recommended for insomnia treatment 1, 4

Special Population Considerations

Elderly Patients (≥65 years)

• Reduce all hypnotic doses by 50%: zolpidem maximum 5 mg, zaleplon 5 mg 4
• Ramelteon 8 mg or low-dose doxepin 3 mg are safest choices due to minimal fall risk and cognitive impairment 4
• Avoid long-acting benzodiazepines completely due to accumulation and increased fall risk 4

Patients with Substance Use History

• Ramelteon is the only appropriate PRN choice due to zero abuse potential and non-DEA-scheduled status 4
• Avoid all benzodiazepines and traditional BzRAs in this population 4

Patients with Respiratory Disorders (Sleep Apnea, COPD)

• Non-benzodiazepines (zaleplon, zolpidem, eszopiclone) preferred due to minimal respiratory depression 4
• Use lower doses: lorazepam 0.25-0.5 mg if benzodiazepine necessary for anxiety 1

Essential Patient Education Before PRN Use

• Treatment goals and realistic expectations - PRN medications provide temporary relief while addressing underlying causes 1, 4
• Safety concerns - avoid alcohol, driving impairment risk, complex sleep behaviors 4
• Potential side effects - daytime sedation, cognitive impairment, fall risk 4
• Importance of behavioral interventions - medication should supplement, not replace, CBT-I for insomnia or psychotherapy for anxiety 1, 4, 2
• Risk of dependence - particularly with benzodiazepines, emphasizing short-term use only 4, 2

Common Pitfalls to Avoid

• Using benzodiazepines as monotherapy for anxiety beyond 3-4 weeks without transitioning to SSRIs/SNRIs 2
• Prescribing PRN hypnotics without implementing or recommending CBT-I, which provides superior long-term outcomes 1, 4
• Failing to adjust doses in elderly patients, leading to increased fall risk and cognitive impairment 4
• Continuing PRN medications long-term without periodic reassessment of need and effectiveness 1, 4
• Using over-the-counter sleep aids assuming they are safer than prescription options 1, 4
• Combining multiple sedatives (e.g., benzodiazepine with high-dose olanzapine), which significantly increases risks 1