Emergency Medical Training – Narcan and Thiamine

Clinical Guide for First Responders: Narcan Reversal and Thiamine Administration

Overview

This guide summarizes frontline recognition, indications, dosing, administration techniques, monitoring, and safety considerations for using naloxone (Narcan) to reverse opioid overdose and thiamine (vitamin B1) to prevent/treat Wernicke encephalopathy in at-risk patients. It’s written for first responders who need rapid, practical steps in the field.

Key principles

Priority: Airway, breathing, circulation (ABC). Support ventilation and oxygen before or while preparing medications.
Naloxone (Narcan): Reverses opioid-induced respiratory depression quickly; titrate to restore adequate spontaneous respiration without precipitating severe withdrawal when possible.
Thiamine: Administer to patients at risk for thiamine deficiency (heavy alcohol use, malnutrition, prolonged vomiting, liver disease) before giving glucose to reduce risk of precipitating Wernicke encephalopathy.

Recognition — when to suspect opioid overdose

Depressed or absent respiratory effort (respiratory rate <10/min or apnea)
Pinpoint pupils (may be absent if mixed intoxication)
Unresponsiveness or markedly decreased level of consciousness
Slow or absent respiratory effort with bradypnea and cyanosis
History or scene clues: opioid paraphernalia, opioid prescription bottles, reports from bystanders

Naloxone (Narcan) — indications and goals

Indicated for suspected opioid-induced respiratory depression or severe sedation with compromised ventilation.
Goal: restore adequate spontaneous respirations and protective airway reflexes, not necessarily full wakefulness.

Naloxone formulations and typical field dosing

Intranasal (IN) spray: 4 mg per spray (0.1 mL of 40 mg/mL) commonly used.
- Adult initial: 4 mg IN once; if no adequate response in 2–3 minutes, repeat every 2–3 minutes as needed (up to multiple doses).
Intramuscular (IM) injection: commonly 0.4 mg — 2 mg per dose historically; modern practice for severe respiratory depression often starts with 0.4–2 mg IM.
- Adult IM: 0.4–2 mg IM; repeat every 2–3 minutes as needed.
Intravenous (IV) injection: 0.04 mg — 0.4 mg titrated for opioid-dependent patients to avoid abrupt withdrawal; for life-threatening respiratory depression, 0.4–2 mg IV may be used.
- IV routes provide fastest onset; titrate to effect.
Auto-injectors follow manufacturer dosing (commonly 2 mg or 4 mg).

Note: In the field, use the formulation available and follow local protocols and scope of practice.

Administration technique

IN: Position patient supine with head slightly elevated; administer half the dose into each nostril if device requires split dosing; hold nostril closed after spray to encourage absorption.
IM: Choose deltoid or lateral thigh; inject at a 90° angle; aspirate only if required by local protocol.
IV: Use standard aseptic technique; administer slowly while monitoring respiratory response.

Monitoring and reassessment

Continuously monitor airway, breathing, circulation, and mental status.
Reassess respiratory rate and oxygenation every 1–2 minutes after naloxone.
Be prepared to provide bag-valve-mask ventilation if respirations do not adequately recover.
Observe for return of opioid toxicity when naloxone effect wanes (naloxone duration shorter than some opioids). If relapse occurs, repeat dosing or continuous infusion per advanced protocols and medical control.
Arrange rapid transport to definitive care; even if responsive, the patient may re-sedate as naloxone wears off.

Adverse effects and special considerations with naloxone

Acute opioid withdrawal (agitation, vomiting, tachycardia, hypertension) — manage airway and safety; limit dose to restore respiration rather than full arousal when possible.
Pulmonary edema and seizures are rare but reported.
Pregnant patients: Naloxone is indicated for maternal opioid overdose; benefit outweighs risk.

Thiamine (Vitamin B1) — rationale and indications

Thiamine is essential for carbohydrate metabolism and neuronal function. Deficiency can cause Wernicke encephalopathy, especially in patients with chronic alcohol use, malnutrition, or prolonged vomiting.
Give thiamine before administering glucose-containing solutions in at-risk patients to reduce the risk of precipitating or worsening Wernicke encephalopathy.

Thiamine dosing for first responders (practical field guidance)

Routine prehospital administration depends on protocols. Typical emergency regimen:
- Adult: 100 mg IV or IM once before glucose in at-risk patients.
- If IV access is available, give 100 mg IV slowly; IM 100 mg is acceptable if IV not available.
Pediatric dosing varies by weight/age—follow local pediatric protocols.

Administration technique for thiamine

IV: Administer slowly (no more than a few mL/minute) when possible.
IM: Inject into a large muscle (deltoid or thigh).
Thiamine is generally well tolerated; anaphylaxis is extremely rare but be prepared to manage allergic reactions.

Integrating naloxone and thiamine in the field

Assess ABCs; provide airway support and high-flow oxygen/ventilation as needed.
If opioid overdose suspected with respiratory compromise, give naloxone immediately (use available route and dose per protocol).
If patient has risk factors for thiamine deficiency and will receive glucose (e.g., hypoglycemia treatment) or is malnourished/heavy alcohol user, administer thiamine 100 mg IV/IM before glucose.
Continue monitoring; secure rapid transport to ED regardless of initial response.

Documentation and communication

Record time, dose, route, and patient response for naloxone and thiamine.
Communicate to receiving facility: number of naloxone doses, patient’s response, risk factors for thiamine deficiency, glucose given or anticipated, and airway interventions performed.

Special scenarios

Mixed overdoses: CNS depressants plus stimulants or alcohol may mask typical signs; treat airway and ventilations first, titrate naloxone.
Pediatric patients: Use pediatric-appropriate naloxone dosing and follow local protocols for thiamine/glucose.
Recurrent overdose after initial reversal: consider longer-acting opioids (e.g., methadone, extended-release formulations) — early ED care may require infusion or repeated dosing.

Quick reference (concise)

Naloxone adult IN: 4 mg every 2–3 min as needed.
Naloxone adult IM/IV: 0.4–2 mg, repeat every 2–3 min as needed; titrate IV.
Thiamine adult: 100 mg IV/IM before glucose in at-risk patients.
Transport all patients to ED; monitor continuously.

Limitations

Follow your local medical protocols and scope of practice; practice and training improve speed and safety.
This guide summarizes common field practice but is not a substitute for medical control or detailed protocol manuals.

Emergency contacts and local medical direction should be followed for any deviations.