What are the typical drugs used for anesthesia?

Anesthesia Drug List

The typical drugs used for anesthesia include induction agents (propofol, thiopental, etomidate, ketamine), maintenance agents (volatile anesthetics: sevoflurane, isoflurane, desflurane, nitrous oxide), neuromuscular blockers (succinylcholine, rocuronium, vecuronium, atracurium), analgesics (fentanyl, remifentanil, alfentanil, morphine), sedatives (midazolam, dexmedetomidine), local anesthetics, and adjuncts (antisialogues, antiemetics). 1, 2

Induction Agents

Intravenous induction agents provide rapid onset of unconsciousness for initiating general anesthesia:

• Propofol is the principal intravenous induction agent, characterized by rapid onset (30 seconds), smooth induction, and quick recovery due to its short half-life of 1.5-3 hours 1, 3, 2, 4
• Thiopental is a rapid-acting barbiturate with very small amounts transferred to breast milk 1, 2
• Etomidate provides hemodynamic stability during induction with rapid redistribution from the CNS 1, 2
• Ketamine is used for its sympathomimetic effects and analgesic properties, with onset in 1-2 minutes and duration of 5-10 minutes 1, 2

Maintenance Agents (Volatile Anesthetics)

Inhaled anesthetics are preferred for maintenance because they allow precise control of anesthetic depth at low cost 5:

• Sevoflurane is widely used with adequate potency and appropriate solubility 1, 2, 5
• Isoflurane has minimal hepatotoxicity risk and appropriate pharmacokinetic properties 1, 2, 6, 5
• Desflurane offers rapid recovery with time to open eyes of 4-9 minutes and time to state name of 7-11 minutes 6, 5
• Nitrous oxide is used as an adjunct due to insufficient potency alone, providing analgesic effects 1, 2, 5
• Halothane is less commonly used due to higher solubility and hepatotoxicity risk 1, 5

Neuromuscular Blocking Agents

Muscle relaxants facilitate intubation and surgical conditions:

• Succinylcholine is a depolarizing agent with rapid onset and short duration 1, 2
• Rocuronium is a non-depolarizing agent that can be rapidly reversed with sugammadex 1, 2
• Vecuronium and atracurium are alternative non-depolarizing agents 1
• Neostigmine and sugammadex are reversal agents 1

Analgesic Agents

Opioids provide intraoperative and postoperative pain control:

• Fentanyl has onset in 2-5 minutes with duration of 30-60 minutes, dosed as bolus 0.5-1 mcg/kg for brief procedures 1, 3, 2
• Remifentanil has ultra-short duration (3-5 minutes) with TCI dosing of 1-3 ng/mL, ideal for procedures requiring rapid recovery 1, 2
• Alfentanil is another short-acting opioid option 1, 2
• Morphine is the standard for postoperative pain management 1, 2

Non-opioid analgesics are essential components of multimodal analgesia:

• Paracetamol (acetaminophen) is safe and widely used 1
• NSAIDs including ibuprofen, diclofenac, naproxen, celecoxib, ketorolac, and parecoxib 1, 2
• Tramadol can be used as rescue analgesia 1
• Metamizole (where available) can be used as loading dose 1

Sedative Agents

Benzodiazepines and alpha-2 agonists provide anxiolysis and sedation:

• Midazolam is a short-acting benzodiazepine with onset in 3-5 minutes, duration of 1-2 hours, dosed as bolus 0.5-1 mg titrated to effect 1, 2
• Dexmedetomidine is an alpha-2 agonist with onset in 1-2 minutes, dosed as bolus 0.5-1 mcg/kg over 5 minutes followed by infusion 0.3-0.6 mcg/kg/h 1, 2
• Diazepam may be considered as a one-off dose but has prolonged half-life due to active metabolites 1

Local Anesthetics

Topical and regional anesthesia agents include:

• Lidocaine in concentrations of 1-10%, with total dose not exceeding 9 mg/kg lean body weight 1
• Co-phenylcaine spray containing lidocaine 125 mg and phenylephrine 1
• Cocaine 10% at doses less than 1.5 mg/kg 1

Adjunctive Medications

Antisialogues reduce secretions during airway procedures:

• Glycopyrronium bromide 0.2-0.4 mg IM or 0.1-0.2 mg IV, with onset in 20 minutes (IM) or 3-5 minutes (IV) 1
• Atropine 0.3-0.6 mg IM or 0.2-0.3 mg IV, less commonly used due to tachycardia 1
• Hyoscine hydrobromide 0.2-0.6 mg IM with longer lasting effects 1

Antiemetics prevent postoperative nausea and vomiting:

• Ondansetron, granisetron, cyclizine, prochlorperazine, dexamethasone, metoclopramide, and domperidone 1

Special Dosing Considerations

For elderly patients or those with significant comorbidities, dose reductions are essential:

• Reduce midazolam dose by at least 20% for patients over 60 years or ASA physical status 3 or above 3
• Reduce propofol dose to 25 mcg/kg/min for elderly patients 3
• Lower doses of intrathecal bupivacaine (less than 10 mg) reduce associated hypotension in elderly patients 1
• Reduced doses of intravenous induction agents should be administered to elderly patients 1

Co-Induction Strategies

Combining agents exploits synergistic effects while reducing individual drug doses and side effects:

• Pre-administration of midazolam 0.03 mg/kg (approximately 2 mg) with propofol reduces awareness risk and propofol dose requirements 7
• Propofol combined with opioids (fentanyl, remifentanil) provides lower pain scores but requires caution for respiratory depression 1, 7
• Ketamine combined with midazolam is important for critically ill patients 7
• Propofol combined with ketamine provides deeper sedation but increases respiratory depression risk 1

Common Pitfalls to Avoid

• Avoid bolus dosing of propofol (use TCI 0.5-1 mcg/mL) and remifentanil to prevent over-sedation and hypoventilation 1
• Caution with dexmedetomidine bolus as it is associated with hypertension and bradycardia 1
• Peak effect of midazolam occurs at 5-10 minutes, so exercise care with multiple doses 1
• Simultaneous spinal and general anesthesia is associated with precipitous blood pressure drops and should be avoided 1, 2
• Opioid use increases postoperative nausea and vomiting 7
• Propofol with opioids can cause severe bradycardia, preventable with vagolytic agents 7