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  1. Sedatives and analgesics. The goal for administering sedatives and analgesics before surgery is to allay the patient’s anxiety, to decrease pain during administration of regional anesthesia or preoperative line placement, and to facilitate smooth induction of anesthesia. The dose of sedatives and analgesics should be reduced or withheld for the elderly, debilitated, or acutely intoxicated patient. The dose should also be decreased in a patient with upper airway obstruction, central apnea, neurologic deterioration, or severe pulmonary disease.
    1. Benzodiazepines.
      1. Midazolam. Midazolam, 1 to 3 mg intravenously or intramuscularly, is a short-acting benzodiazepine that provides excellent anterograde amnesia and anxiolysis. It plays a role in preventing PONV. It is known to cause delirium in the elderly and to be synergistic with opioids in causing respiratory depression.
      2. Lorazepam. Lorazepam, 1 to 2 mg orally or intravenously, may cause more prolonged amnesia and postoperative sedation than midazolam.
    2. Opioids. Opioids may be given preoperatively to a patient who has, or is anticipated to have, significant pain or to a patient who is opioid dependent. The opioid-dependent patient should receive sufficient premedication to overcome tolerance and to prevent perioperative withdrawal. Intravenous fentanyl is ideally dosed at least 2 to 5 minutes prior to airway instrumentation so that its effect blunts the reaction from laryngoscopy.
  2. Anticholinergics. Anticholinergics are not frequently used for premedication. Glycopyrrolate, 0.2 to 0.4 mg intravenously for adults and 10 to 20 μg/kg for pediatric patients, may be given in conjunction with ketamine as an antisialagogue. Occasionally, this antisialagogue effect is desirable during oral surgery, bronchoscopy, fiberoptic intubation, or to treat secretions related to recent smoking cessation.
  3. Antiemetics. Antiemetics may be given prior to induction or intraoperatively to prevent PONV (see Chapter 37). Adequate prophylaxis includes the use of at least two antiemetics with differing mechanisms of action (see Table 1.3).

    Table 1-3 Antiemetic Agents

    Antiemetic AgentMechanism of ActionSide EffectsDose
    OndansetronSerotonin (5-HT3) receptor antagonistDizziness, headache, and QTc prolongation4 mg intravenously
    DroperidolaDopamine (D2) receptor antagonistDystonia, prolonged QTc, and decreased seizure threshold0.5-1.25 mg intravenously
    HaloperidolD2 receptor antagonistDystonia, prolonged QTc, and decreased seizure threshold1 mg intravenously
    DexamethasoneUnknownAnal/vulvar pruritus and hyperglycemia4 mg intravenously
    MetoclopramideDopamine receptor antagonistGI upset with abdominal cramping and dystonia10 mg intravenously
    PromethazineAntihistamineSedation and decreased seizure threshold6.25 mg intravenously
    ScopolamineAnticholinergicDry mouth, blurred vision, confusion, and urinary retention1.5 mg transdermally

    a The Food and Drug Administration requires 2 to 3 h of electrocardiogram (ECG) monitoring following administration given the risk of QTc prolongation and torsades de pointes.

  4. Aspiration risk-mitigating agents. Aspiration risk-mitigating agents may be warranted on the day of surgery in the at-risk patient (see Section VI.H).