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# Attenuation Drugs (General Anesthesia & Sedation Agents)
*Note: As "Attenuation drugs" is a broad clinical term often referring to agents used to attenuate the sympathetic response to laryngoscopy (e.g., opioids, beta-blockers, lidocaine), this profile focuses on common pharmacological agents used for hemodynamic attenuation.*
## Overview
Attenuation agents are utilized during induction of anesthesia to blunt the hypertensive and tachycardic stress response provoked by airway manipulation, intubation, and surgical incision.
## Primary Indications
* Blunting hemodynamics during endotracheal intubation.
* Management of intraoperative sympathetic surges.
## Adult Dosing
* **Fentanyl:** 1–3 mcg/kg IV (administer 3–5 minutes prior to induction).
* **Lidocaine (preservative-free):** 1.5 mg/kg IV (administer 2–3 minutes prior to intubation).
* **Esmolol:** 0.5–1.0 mg/kg IV bolus (prior to intubation) or 100–300 mcg/kg/min infusion.
* **Remifentanil:** 0.5–1 mcg/kg IV over 30–60 seconds.
## Pediatric Dosing
* **Fentanyl:** 1–2 mcg/kg IV.
* **Lidocaine:** 1 mg/kg IV.
* *Note: Dosages for pediatric patients are highly age- and weight-dependent; strictly follow local institutional protocols.*
## Dose Adjustments
* **Renal/Hepatic impairment:** Reduce doses of opioids (Fentanyl, Remifentanil) as clearance may be prolonged.
* **Elderly/Debilitated:** Reduce induction dosages by 30–50% due to decreased cardiovascular reserve and increased drug sensitivity.
## Contraindications
* **Hypersensitivity:** Known allergy to the specific agent.
* **Esmolol:** Uncompensated heart failure, severe bradycardia, or heart block (greater than first-degree).
* **Opioids:** Acute respiratory depression (unless in a controlled, ventilated setting).
## Adverse Effects
* **Opioids:** Chest wall rigidity, bradycardia, respiratory depression.
* **Lidocaine:** High-dose toxicity includes circumoral numbness, tinnitus, seizures, and arrhythmias.
* **Esmolol:** Hypotension, bradycardia.
## Key Drug Interactions
* **Esmolol:** Additive bradycardic effects with non-dihydropyridine calcium channel blockers (verapamil/diltiazem).
* **Opioids:** Potentiated respiratory depression with benzodiazepines or concurrent inhaled anesthetics.
## Monitoring
* **Continuous:** ECG (heart rate/rhythm), pulse oximetry, capnography, and non-invasive blood pressure (frequent intervals per clinician discretion).
## Clinical Pearls
* **Timing is critical:** Peak effect must coincide with the stimulus (e.g., laryngoscopy).
* **Hemodynamic Reserve:** In patients with severe autonomic dysfunction or hypovolemia, smaller, titrated doses are mandatory to prevent cardiovascular collapse.
* **Systemic Absorption:** Local anesthetic systemic toxicity (LAST) must always be considered when using lidocaine.
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**Educational Disclaimer:** This information is for educational purposes only. Clinical practice varies by institution and patient status. Always verify current prescribing information, institutional protocols, and patient-specific contraindications via reliable clinical resources (e.g., UpToDate, Lexicomp) before administration.
