Active Labor Anesthesia

1. See Also
   1. Latent Labor Anesthesia
   2. Non-Pharmacologic Pain Control in Labor
   3. Epidural Anesthesia
   4. Intrathecal Morphine
   5. Paracervical Block
   6. Pudendal Block
2. Preparations: Non-Opioids
   1. Acetaminophen
      1. Dosing: 1000 mg orally every 6 hours prn
   2. Diphenhydramine
      1. Dosing: 25-50 mg orally, IV or IM every 4-6 hours
   3. Promethazine (Phenergan)
      1. Dosing: 25-50 mg orally or IM, 12.5 to 25 mg IV every 4-6 hours
3. Preparations: Systemic Opioids (30 minutes to 2 hours relief)
   1. Nalbuphine (Nubain)
      1. Dose: 10-20 mg IV, IM or SC every 3 hours prn
      2. Onset in 2-3 minutes with IV Nalbuphine and 15 minutes with IM or SQ dosing
   2. Morphine
      1. Active Labor: 2-4 mg IV every 2-4 hours (onset in minutes)
      2. Latent Labor: 5-10 mg IM every 4 hours (onset in 40 minutes)
   3. Butorphanol (Stadol)
      1. IV: 1-2 mg IV every 4-6 hours prn (onset in 5-10 minutes)
      2. IM: 2-4 mg every 4-6 hours prn (onset in 30-60 minutes)
   4. Fentanyl (Sublimaze)
      1. 50-100 mcg IV every hour prn (onset in minutes)
   5. Consider Patient Controlled Analgesia
      1. Fentanyl
      2. Alfenta
      3. Remifentanil (Ultiva)
         1. Rapid and predictable elimination with less neonatal sedation
         2. May be associated with greater Pruritus and maternal sedation than with other Opioids
         3. Background infusion: 0.05 to 0.1 mcg/kg
         4. Bolus: 0.2 to 0.5 mcg/kg
         5. Lockout: 2-3 minutes
      4. Nitrous Oxide (50/50 mix with oxygen)
         1. Adverse effects include Nausea, Vomiting, Dizziness
         2. Onset is rapid with mask application, and clears rapidly with mask removal
         3. Klomp (2012) Cochrane Database Syst Rev (9): CD009351 [PubMed]
4. Preparations: Spinal Anesthesia or Neuraxial Anesthesia (3-6 hours relief)
   1. Indications
      1. Cervix dilated to 4 cm or beyond
   2. Options
      1. Intrathecal Morphine
      2. Epidural Anesthesia
      3. Combination Regional Anesthesia in Labor (Walking Epidural)
5. Preparations: Regional Labor Anesthesia
   1. Paracervical Block
   2. Pudendal Block
6. References
   1. Smith (2021) Am Fam Physician 103(6): 355-64 [PubMed]