What drugs are commonly used in the operating room?

Drugs Commonly Used in the Operating Room

The operating room utilizes a standardized multimodal drug approach centered on induction agents (propofol 1-3 mg/kg or inhalational sevoflurane), opioid analgesics (fentanyl 1-2 mcg/kg), neuromuscular blocking agents, and adjunctive medications for specific surgical needs, with all medications requiring rigorous safety protocols including standardized labeling, barcode verification, and double-checking of high-risk drugs. 1, 2

Core Anesthetic Agents

Induction Agents

• Propofol is the primary intravenous induction agent at 1-3 mg/kg for adults, with dose reduction in elderly and hemodynamically unstable patients 3, 4
• Sevoflurane serves as the preferred inhalational agent for mask induction, particularly in pediatric patients due to its nonpungent odor, with maintenance at 0.5-2.0 MAC 5
• Propofol requires slower administration (approximately 20 mg every 10 seconds) in neurosurgical cases to avoid decreases in cerebral perfusion pressure 3

Opioid Analgesics

• Fentanyl 1-2 mcg/kg is the standard intraoperative opioid, with 1 mcg/kg for minor procedures and 2 mcg/kg for major/invasive procedures 1, 2
• Alternative opioids include remifentanil (0.05-0.3 mcg/kg/min continuous infusion), sufentanil (0.5-1 mcg/kg bolus), morphine (25-100 mcg/kg), and piritramide (0.05-0.15 mg/kg) 1
• For breakthrough pain in PACU, use reduced fentanyl dosing of 0.5-1.0 mcg/kg titrated to effect 1

Neuromuscular Blocking Agents

• Vecuronium (0.1-0.2 mg/kg) and succinylcholine are standard agents for intubation and muscle relaxation 3, 5
• Propofol does not significantly alter the onset, intensity, or duration of commonly used neuromuscular blocking agents 3

Adjunctive Medications

Co-Analgesics and Sedatives

• Midazolam 0.02 mg/kg (or 1-2 mg IV in adults) provides anxiolysis and amnesia 2, 6, 4
• Ketamine 0.5 mg/kg (or 0.25-0.5 mg/kg for S-ketamine) serves as a co-analgesic, reducing opioid requirements by 30-50% 1, 6
• Dexmedetomidine 0.5-1 mcg/kg loading dose provides sympatholysis and sedation, though caution is needed for bradycardia and hypotension 1, 6

Non-Opioid Analgesics

• Paracetamol (acetaminophen): Loading dose 15-20 mg/kg IV, then 10-15 mg/kg every 6-8 hours (maximum 60 mg/kg/day) 1
• NSAIDs: Ketorolac 0.5-1 mg/kg (up to 30 mg single intraoperative dose), ibuprofen 10 mg/kg every 8 hours, or diclofenac 0.5-1 mg/kg every 8 hours 1
• Metamizole 10-15 mg/kg every 8 hours for short-term postoperative use only 1

Antiemetics and Corticosteroids

• Ondansetron is routinely administered for prophylaxis of postoperative nausea and vomiting 4
• Dexamethasone 0.15-0.25 mg/kg (maximum 0.5 mg/kg) or methylprednisolone 1 mg/kg reduces postoperative swelling and inflammation 1

Premedication

• Midazolam 2 mg (1 mg in children) combined with pethidine 25 mg and glycopyrrolate 0.2 mg represents standard premedication practice 4
• Premedication with opioids and sedatives reduces propofol induction requirements but increases risk of hypotension and respiratory depression 3

Regional Anesthesia Agents

Local Anesthetics

• Long-acting local anesthetics (bupivacaine, ropivacaine) are used for regional blocks including caudal, epidural, and peripheral nerve blocks 1
• Intravenous lidocaine 1.5 mg/kg bolus followed by 1.5 mg/kg/h infusion provides systemic analgesia 1
• Only preservative-free local anesthetics should be used for neuraxial administration, with clear segregation from intravenous medications 1

Regional Block Adjuvants

• Clonidine 1-3 mcg/kg can be added to regional blocks to prolong analgesia 1

Critical Medication Safety Protocols

Labeling and Verification Requirements

• Every medication must be labeled with drug name, date, and concentration before administration 1
• Barcode systems with audible and visual cues should be used for all medication administration when available 1
• Unlabeled syringes must be immediately discarded without exception 1

High-Risk Drug Management

• Two-person verification is mandatory for high-risk medications (concentrated electrolytes, insulin, heparin) and weight-based doses 1
• No concentrated drugs should be stored in standard anesthesia carts; pharmacy should provide pre-diluted high-risk drugs 1
• Large volume epinephrine should be removed from operating rooms 1

Cart Organization and Inventory

• Drug trays must be standardized across all locations with clear labeling and modular systems 1
• Single-use vials are preferable; multi-dose vials must be discarded at end of case 1
• Regional anesthetic solutions must be clearly segregated from intravenous medications 1

Administration Protocols

• Read and verify every vial, ampoule, and syringe label before administration using barcode systems or two-person checks 1
• Smart pumps with standardized libraries, guardrails, and alerts must be used for all infusions 1
• Route-specific administration sets (color-coded: yellow for epidural, red for arterial) with labels on every infusion line and port 1

Common Pitfalls and How to Avoid Them

Drug Interaction Risks

• Fentanyl with propofol in pediatric patients can cause serious bradycardia; monitor heart rate continuously and have atropine readily available 3
• Valproate increases propofol blood levels; reduce propofol dose and monitor for increased sedation or cardiorespiratory depression 3
• Premedication with opioids and sedatives increases propofol's hypotensive effects; correct fluid deficits before induction 3

Dosing Errors

• Wrong dose errors (miscalculation, concentration errors, infusion rate errors) account for the majority of medication errors at 5.3% of administrations 1
• Establish weight-based dose limits with automated alerts in anesthesia information systems 1
• Use cognitive aids, checklists, and infusion rate charts at point of care 1

Syringe and Ampoule Swaps

• Substitution errors (syringe or ampoule swaps) are common and preventable through standardized color-coded labeling per ISO standards 1
• Implement "clean sweep" protocol: discard all syringes, containers, and multi-dose vials at end of case unless connected to patient 1

Medication Reconciliation Failures

• Complete medication reconciliation must occur with single location for recording medications across all surgical phases (pre, intra, PACU) 1
• Time-out must include patient identification, weight, allergies, and medication information such as antibiotics given 1

Sterile Field Medication Errors

• Only one medication should be passed to sterile field at a time, checked and verified aloud by two persons 1
• All sterile field medications must be labeled with drug name, date, and concentration; any unlabeled medication must be discarded 1
• Topical or irrigation fluids must be segregated and never placed in parenteral syringes 1

Handover Communication Gaps

• Handovers (shift changes, relief, PACU/ICU transfers) require protocol-driven review of all drugs given and all drugs remaining on cart or sterile field 1
• Verbal medication orders must be verified by speak-back, announced when given, and entered into chart (preferably recorded in anesthesia information management system) 1