What anesthesia drugs should be avoided in pregnant patients?

Anesthesia Drugs to Avoid During Pregnancy

Ketamine, benzodiazepines (especially diazepam), and volatile anesthetics should be avoided when possible in pregnant patients due to potential risks to fetal development. 1, 2

Intravenous Anesthetic Agents

• Propofol: FDA pregnancy category B but should be used with caution. Animal studies show decreased pup survival and increased neuronal apoptosis in developing brains when administered during late gestation 2
• Ketamine: Should be avoided when possible as it crosses the placenta and may cause neuronal apoptosis in the developing fetal brain 1, 3
• Etomidate: Preferred over ketamine but should still be used with caution 1
• Thiopental: Can be used but with careful consideration of maternal and fetal effects 1

Neuromuscular Blocking Agents

• Cisatracurium and rocuronium are the only FDA pregnancy category B neuromuscular blocking agents and are preferred in pregnant patients 1
• Vecuronium, atracurium, and pancuronium are pregnancy class C drugs and should be avoided for long-term infusion, especially in the first trimester 1
• All neuromuscular blocking agents except cisatracurium cross the placental barrier, which should be considered when selecting an agent 1

Sedatives and Anxiolytics

• Benzodiazepines: Should be avoided, especially diazepam, which has an active metabolite with prolonged half-life 1
• Midazolam: If sedation is necessary, midazolam is preferred over diazepam due to shorter half-life, but should still be used with caution 1
• Dexmedetomidine: Limited data in pregnancy; use with caution 1

Volatile Anesthetics

• Sevoflurane, isoflurane, desflurane, and halothane: These agents have been associated with increased neuronal and oligodendrocyte apoptosis in the developing brain when used during the third trimester 2, 3
• If general anesthesia is unavoidable, minimize exposure time and concentration 3

Opioid Analgesics

• Pethidine (meperidine): Should be avoided due to its long-acting metabolite norpethidine and risk of neonatal respiratory depression 4
• Oxycodone: Should be avoided due to higher risk of sedation compared to other opioids 1
• Tramadol: Use with caution and close monitoring 1
• Remifentanil: Preferred if opioid analgesia is necessary due to short context-sensitive half-life 1, 4

Safe Alternatives

• Local anesthetics: Lidocaine with epinephrine (1:200,000) is considered safe throughout pregnancy 5, 6
• Non-opioid analgesics: Paracetamol (acetaminophen) is considered the safest analgesic during pregnancy 7, 8
• Regional anesthesia: Whenever practical, regional anesthesia is preferred over general anesthesia to minimize fetal exposure to medications 3, 4

Important Considerations

• Maintain maternal oxygenation, perfusion, and homeostasis during anesthesia to ensure optimal fetal outcomes 3
• Position pregnant patients in left lateral tilt after 20 weeks gestation to prevent aortocaval compression 3
• Monitor maternal vital signs closely, especially blood pressure and oxygenation 6
• When surgery is indicated during pregnancy, use the least extensive anesthetic that is practical 3

Pitfalls to Avoid

• Avoid nitrous oxide in early pregnancy due to potential association with pregnancy loss 3
• Never discontinue neuromuscular blocking agents abruptly prior to clinical determination of brain death 1
• Avoid aspirin in analgesic doses during pregnancy 1
• Do not assume that drugs safe for breastfeeding are also safe during pregnancy, as placental transfer differs from breast milk transfer 8