Phenobarbital in AWS

Phenobarbital for Alcohol Withdrawal Syndrome (AWS)

Use this as a ready-to-paste clinical note and quick order guide. (Last updated: Oct 26, 2025)

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Chart Note (paste-as-is)

Assessment/Plan – Alcohol Withdrawal Syndrome: Patient with suspected/confirmed alcohol withdrawal exhibiting autonomic hyperactivity and agitation. High risk for complicated withdrawal given history of heavy alcohol use (DTs/seizures/prior ICU stay as applicable) and current clinical trajectory. We will use a phenobarbital-based protocol for GABAergic replacement and NMDA antagonism, aiming for light sedation with airway and hemodynamic safety.

• Targets: CIWA-Ar < 10 (if usable) or RASS 0 to –1; prevent seizures/DTs; avoid respiratory depression.
• Contraindications reviewed: severe hepatic failure, marked respiratory depression, porphyria, recent large benzodiazepine/opioid load. Risks/benefits discussed with team.

Phenobarbital Dosing (weight-based loading with monitored titration):

1. Load: Total target 10–15 mg/kg IV (use Ideal Body Weight). Give initial 260 mg IV over 15–30 min, then 130–260 mg IV q30–60 min PRN to target (max cumulative 15 mg/kg).
2. Maintenance (after clinical stabilization): Phenobarbital 60–120 mg PO/IV q12h × 24–48 h, then taper by 30–60 mg every 12–24 h over 2–4 days as symptoms allow.
3. If combining with benzodiazepines: minimize/avoid co-administration; if needed for breakthrough, use reduced-dose lorazepam 0.5–1 mg IV PRN with close monitoring.

Monitoring/Safety:

• Continuous pulse oximetry and cardiorespiratory monitoring during loading and first night; q1h vitals until stable, then q2–4h.
• Neuro checks q1–2h during titration; hold further doses for RASS ≤ –2, RR < 10, SpO₂ < 92% on baseline O₂, or MAP < 65 mmHg.
• Basic labs: BMP/Mg/Phos now and in AM; consider ammonia/LFTs if hepatic disease suspected.

Adjuncts:

• Thiamine 100 mg IV before glucose (consider 200–500 mg IV if high Wernicke risk), plus folate and multivitamin.
• Fluids and electrolytes as needed; replete Mg/Phos aggressively for seizure prevention and refeeding risk.
• Consider clonidine or beta-blocker only for autonomic symptoms after adequate GABAergic coverage; avoid masking undertreatment.

Escalation/Rescue: If persistent agitation or seizures despite cumulative phenobarbital > 10–15 mg/kg, evaluate for alternate/complicating diagnoses (e.g., stimulants, head injury, infection, hepatic encephalopathy). Consider ICU sedation (e.g., propofol) with airway protection.

Disposition/Wean: Reduce to oral taper once symptom-controlled for 24 h; discontinue when CIWA-Ar remains < 8 without PRNs. Provide alcohol-cessation counseling, nutrition, and arrange addiction medicine follow-up.

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Quick Orders (compact)

• Phenobarbital Load: 260 mg IV now (over 15–30 min); then 130–260 mg IV q30–60 min PRN to RASS 0 to –1 or CIWA < 10 (max total 15 mg/kg).
• Maintenance: 60–120 mg PO/IV q12h × 24–48 h, then taper by 30–60 mg per dose q12–24h over 2–4 days.
• Hold parameters: RASS ≤ –2, RR < 10, SpO₂ < 92% despite baseline O₂, MAP < 65.
• Adjuncts: Thiamine 100 mg IV before glucose; folate; MVI; Mg/Phos repletion protocols; IVF as needed.
• Monitoring: Telemetry + continuous pulse ox; vitals q1h during loading then q2–4h; BMP/Mg/Phos now and AM.

Weight-Based Loading Guide (Ideal Body Weight)

IBW (kg)	10 mg/kg (total)	15 mg/kg (total)	Typical Split (examples)
50	500 mg	750 mg	260 mg → 130–260 mg PRN to target
60	600 mg	900 mg	260 mg → 130–260 mg PRN
70	700 mg	1050 mg	260 mg → 130–260 mg PRN
80	800 mg	1200 mg	260 mg → 130–260 mg PRN
90	900 mg	1350 mg	260 mg → 130–260 mg PRN
100	1000 mg	1500 mg	260 mg → 130–260 mg PRN

*Cap total load at 15 mg/kg. Use clinical endpoints (RASS/CIWA) rather than numeric dose alone.

Contraindications, Cautions, and Interactions

• Severe hepatic failure, significant respiratory depression, porphyria.
• Additive CNS/respiratory depression with benzodiazepines, opioids, propofol, ethanol, gabapentinoids.
• Enzyme induction (CYPs) may reduce efficacy of some meds over days; not usually acute-phase limiting.
• Consider dose reduction and slower titration in elderly, frail, or suspected OSA/COPD with CO₂ retention.

Operational Pearls

• Prefer phenobarbital-forward strategy when benzodiazepine-resistant or when prior very high benzo needs.
• Use one primary sedative strategy to avoid stacking sedatives; document a clear “hold” rule for the bedside nurse.
• Reassess for alternate diagnoses (trauma, infection, toxic co-ingestants) if unusually high doses are required.

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Disclaimer: Educational template; adjust to patient-specific factors, local formulary, monitoring capabilities, and institutional policy.