Editors: Susla, Gregory M.; Suffredini, Anthony F.; McAreavey, Dorothea; Solomon, Michael A.; Hoffman, William D.; Nyquist, Paul; Ognibene, Frederick P.; Shelhamer, James H.; Masur, Henry
Title: Handbook of Critical Care Drug Therapy, 3rd Edition
> Table of Contents > Chapter 2 - Anesthesia: Analgesia, Sedation, and Neuromuscular Blockade
Chapter 2
Anesthesia: Analgesia, Sedation, and Neuromuscular Blockade


TABLE 2.1. Commonly Used Agents for Intravenous Sedation/Anesthesia
Drug Initial IV Dosagea Maintenance Infusiona Comments
Barbiturates
Pentobarbital 5–20 mg/kg Onset: <1 min Duration: 15 min 1–4 mg/kg/h Infuse loading dose over 2 h
Rapid administration produces hypotension and hemodynamic instability
Thiopental 3–4 mg/kg Onset: 10–20 s Duration: 5–15 min Not applicable Alkaline solution; decreases cardiac index
Benzodiazepines
Diazepam 0.1–0.2 mg/kg Onset: 1–3 min Duration: 1–2 h Not applicable Active metabolite with long half-life (desmethyldiazepam) contributes to activity
Lorazepam 0.04 mg/kg Onset: 5–15 min Duration: 1–6 h 0.02–0.1 mg/kg/h No active metabolites
Approximately 5 times more potent than diazepam
Midazolam 0.025–0.035 mg/kg Onset: 1–3 min Duration: 30 min–3 h 0.05–5 µg/kg/min Elderly patients may develop apnea when midazolam is administered with narcotics
Approximately 3–4 times more potent than diazepam
Active metabolites accumulate in renal failure
Unpredictable elimination in critically ill patients (e.g., shock, liver failure)
Initial dose: 0.5–1 mg and titrate to effect in 0.5–2 mg increments
Other
Propofol 1–2 mg/kg Onset: <1 min Duration: 5–10 min 5–75 µg/kg/min Generally a rapid recovery
Pain on injection is common with peripheral administration
Hypotension may occur especially with rapid bolus in hypovolemic or elderly patients
Propofol may increase serum triglyceride levels when used at high infusion rates; take caution when using in patients with pancreatitis
Doses of propofol of 5 mg/kg/h have been associated with cardiac failure and death
Safety of propofol has not been established for ICU sedation of children
Propofol contains 1.4 mmol of PO4=/100 ml
Dexmedeto- midine 1 µg/kg IV over 10 min 0.2–0.7 µg/kg/h for up to 24 h Alpha-2 adrenergic agonist with analgesic and sedative properties
Numerous cardiovascular effects including brady- and tachyarrhythmias, hyper- and hypotension, and atrioventricular block
Does not produce respiratory depression
Ketamine 1–2 mg/kg (or 5–10 mg/kg IM) Onset: <1 min Duration: 5–10 min 9–45 µg/kg/min Usually preserves airway reflexes
Central sympathetic stimulation; hypertension; tachycardia; advantageous in hypovolemic patients
Tachyphylaxis is rare
Etomidate 0.3–0.4 mg/kg Onset: <1 min Duration: 3–5 min Not recommended
Produces adrenal suppression in continuous infusion
Minimal cardiovascular effects
Myoclonic muscle movements
Pain on IV injection
Remifentanil 0.05 µg/kg Onset: <1 min Duration: <4 min 0.05–0.2 µg/kg/min Ultrashort acting narcotic analgesic; used primarily as an intraoperative analgesic; elimination not dependent on liver or kidney function
CNS, central nervous system; ICU, intensive care unit; IM, intramuscular; IV, intravenous
aBolus doses and rates of infusion should be individualized to provide the desired level of sedation with consideration of potential hemodynamic compromise. Doses should generally be reduced for elderly and hypovolemic patients. It may be beneficial to wake patients daily and assess their CNS function during maintenance infusions to determine the minimal dose required for sedation.
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TABLE 2.2. Tracheal Intubation Techniques
Technique Clinical Setting Procedural Features Cautions
All listed below Indications: Upper airway obstruction
Airway protection
Tracheal toilet
Minimum required monitoring ECG, BP, pulse oximetry
Prepare patient for 100% O2
Establish IV access for rapid administration of resuscitative drugs and fluids if necessary
Equipment and drugs: Oxygen bag-mask ventilation equipment, monitors, suction laryngoscopes, ETT, stylettes, cuff, syringes, “Code Blue” cart
Anesthetics: Neuromuscular blocking agents, Sedative/hypnotic agents
Aspiration
Loss of airway
Dental damage
Trauma to airway
Hemodynamic compromise
Awake Anticipated difficult laryngoscopy
Full stomach
Minimize risk of airway loss as a result of sedation or neuromuscular blockade
Assessment and protection of neurologic function in cervical spine instability
Can be performed without depression of airway reflexes
Requires patient cooperation
Patient maintains airway and ventilation Vomiting from pharyngeal stimulation
Hypertension and tachycardic response to intubation is undesirable in certain clinical settings (e.g., myocardial ischemia, cerebral or aortic aneurysm)
Topical anesthesia of larynx or nerve blocks of larynx obtunds protective airway reflexes
Conscious: Oral Allows largest diameter ETT Topical anesthesia of pharynx or pharyngeal nerve blocks
Intubation with direct vision
 
Conscious: Blind nasal   Apply vasoconstrictor and topical anesthetic to nasal mucosa
Gently dilate nasal passage with soft nasal airways
Gently advance ETT from nose to trachea during inhalation
Nasal bleeding, avoid in coagulopathic patients
Sinusitis
Avoid in craniofacial trauma
Fiberoptic (oral or nasal)   Consider administering an antisialagogue (glycopyrrolate 0.2 mg IV)
Topical anesthetic and vasoconstrictor (for nasal)
Insert bronchoscope through ETT and directly into trachea
Advance ETT over bronchoscope and remove bronchoscope
 
Not Awake Uncooperative patients
Preexisting loss of consciousness (e.g., cardiac arrest, heavy sedation)
Blunts tachycardic and hypertensive response
Minimizes unpleasantness of procedure
  Risk of apnea, aspiration, airway loss
Unsedated unconscious Cardiac arrest Bag-mask ventilation until intubation equipment available
Immediate oral laryngoscopy and intubation
 
Rapid-sequence: oral (see Table 2.3) Full stomach or risk of aspiration in a patient without an anatomically difficult airway for laryngoscopy Administration of sedative and neuromuscular blocking agents
Cricoid pressure
Rapid intubation after onset of neuromuscular blockade
Check ETT placement
Remove cricoid pressure
Risk of airway loss
Hemodynamic compromise may result from sedation or positive pressure ventilation
Reintubation Nonfunctioning ETT (e.g., cuff leak)
Placement of an ETT with different features (e.g., larger diameter)
Sedate and administer neuromuscular blockade Chronically intubated patients may have swelling or traumatic changes of larynx making reintubation difficult
Patients who are dependent on high oxygen concentrations or PEEP may become hypoxemic
Direct vision extubation and reintubation Laryngoscopy possible Perform laryngoscopy with existing ETT in place
If glottis is visualized, remove existing ETT and replace with new one
Loss of airway
Styletted reintubationa Difficult laryngoscopy anticipated Insert stylette into existing ETT
Remove ETT without removing stylette
Insert new ETT over stylette
 
BP, blood pressure; ETT, endotracheal tube; ECG, electrocardiogram; IV, intravenous; PEEP, positive end-expiratory pressure
aaRefers to specific intubating stylettes and not to those routinely used to stiffen ETT during routine intubation.
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TABLE 2.3. Suggested Drugs for Rapid Sequence Intubation
Drug Dosage Comment
Sedatives/Anesthetics
Thiopental 3–4 mg/kg IV Reduce dose in elderly and hemodynamically unstable patients (0.25–1 mg/kg)
May produce hypotension and hemodynamic instability
Blunts intracranial hypertensive response to intubation and is useful in hemodynamically stable patients with elevated ICP
Ketamine 1–2 mg/kg IV
4–10 mg/kg IM
Useful in hypovolemic patients as this drug tends to support the circulation; may rarely produce myocardial depression
Produces hypertension, tachycardia, and elevates ICP; therefore, avoid in patients with myocardial ischemia, severe hypertension, or intracranial mass lesions
Etomidate 0.3–0.4 mg/kg IV Hemodynamic stability
Patients often have benign nonpurposeful muscle movements during induction which may be blunted by low doses of fentanyl (50–100 µg)
Propofol 1–2.5 mg/kg IV Reduce dose in elderly and hemodynamically unstable patients (0.25–0.5 mg/kg)
May produce hypotension and hemodynamic instability
Muscle Relaxantsa
Cisatracurium 0.15–0.2 mg/kg IV Slower in onset than succinylcholine
Less histamine release than atracurium
Hemodynamic stability
Duration of action is dose-dependent (30 min–1 h)
Rocuronium 0.6–1.2 mg/kg IV Reported as most rapid onset of nondepolarizing neuromuscular blocking drugs (60–90 s)
Not recommended in Caesarean section patients
Hemodynamic stability
Duration of action is dose dependent (30 min–1 h)
Succinylcholine 1 mg/kg IV Depolarizing agent
Because of rapidity of onset, drug of choice unless specifically contraindicated (see Table 2.4)
Duration of action [congruent]10 min for patients with normal pseudocholinesterase activity
Vecuronium 0.1–0.28 mg/kg Slower onset than succinylcholine
Hemodynamic stability
Duration of action is dose dependent (30 min–1 h)
ICP, intracranial pressure; IM, intramuscular; IV, intravenous
aFor most clinical situations, cost may be the overriding consideration when choosing among the available nondepolarizing muscle relaxants.
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TABLE 2.4. Neuromuscular Blockade—Bolus Dosing
Agent Dosage Onset/Duration Comments
Depolarizing Relaxant
Succinylcholinea Bolus: 1–2 mg/kg Onset: 1 min
Duration: 10 min
Prolonged effect in pseudocholinesterase deficiencies
Contraindications: family history of malignant hyperthermia, neuromuscular disease, hyperkalemia, open eye injury, major tissue injury (burns, trauma, crush); increased intracranial pressure; not indicated for routine use in children or adolescents
Side effects: bradycardia (especially in children), tachycardia, increased serum potassium
Nondepolarizing Relaxants
Atracurium Bolus: 0.5 mg/kg Onset: 2 min
Duration: 30–40 min
Rapid injection of atracurium bolus doses >0.6 mg/kg releases histamine and may precipitate asthma or hypotension
Metabolized in the plasma by Hofmann elimination and ester hydrolysis
Duration not prolonged by renal or liver failure; otherwise, see comments with vecuronium
Cisatracurium Bolus: 0.15 mg/kg Onset: 2 min
Duration: 30–40 min
Less histamine release than racemic atracurium (see above)
Metabolism and duration of action similar to atracurium
Mivacurium Bolus: 0.15 mg/kg followed in 30 s by 0.10 mg/kg Onset: 1.5 min
Duration: 25 min
Inject over 30 s
May cause histamine release
Metabolized by pseudocholinesterase
Rocuronium Bolus: 0.6 mg/kg Onset: 1 min
Duration: 30–40 min
Metabolized by liver, prolonged duration in hepatic failure
Duration not prolonged by renal failure
Used when succinylcholine is contraindicated or not preferred
Vecuronium Bolus: 0.1 mg/kg Onset: 2 min
Duration: >30–40 min
Metabolized by liver; duration not significantly prolonged by renal failure
  Bolus: 0.28 mg/kg Onset: 60 s
Duration: 100 min
Used when succinylcholine is contraindicated or not preferred
No cardiovascular effects
aThe pharmaceutical companies that manufacture succinylcholine have changed the package insert to indicate that the drug should not be used routinely in children, except for airway emergencies, risk of aspiration, and special situations. This practice is a response to reported complications including malignant hyperthermia, masseter muscle rigidity, rhabdomyolysis, and sudden cardiac arrest in children with undiagnosed myopathies.
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TABLE 2.5. Neuromuscular Blockade—Maintenance Dosing
Agent Maintenance Dosage Duration Comments
Short Acting
Mivacurium 0.01–0.1 mg/kg
Infusion: 9–10 µg/kg/min
15 min Metabolized by pseudocholinesterase
Intermediate Acting
Atracuriuma 0.08–0.10 mg/kg
Infusion: 5–9 µg/kg/min
15–25 min Elimination independent of renal or hepatic function
Cisatracuriuma 0.01–0.02 mg/kg
Infusion: 1–2 µg/kg/min
15–25 min Elimination independent of renal or hepatic function
Rocuroniuma 0.1–0.2 mg/kg
Infusion: 10–12 µg/kg/min
10–25 min Metabolized primarily by the liver
Active metabolite significantly less potent than parent compound
Vecuroniuma 0.01–0.15 mg/kg
Infusion: 1 µg/kg/min
15–25 min Bile is main route of elimination
Minimal dependence on renal function, although active metabolite accumulates in renal failure
Long Acting
Doxacuriuma 0.005–0.01 mg/kg
Infusion: 0.25 µg/kg/min (not generally recommended)
35–45 min Cardiovascular stability
Predominantly renal elimination significant accumulation in renal failure
Pancuroniuma 0.01–0.015 mg/kg
Infusion: 1 µg/kg/min (not generally recommended)
25–60 min Tachycardia (vagolytic effect)
Active metabolite accumulates in renal failure
aProlonged infusions of neuromuscular blocking drugs have been associated with undesirable prolongation of neuromuscular blockade and myopathy. When indicated, general guidelines for use of infusions include: (a) periodic monitoring of neuromuscular function (train-of-four stimulation) during administration of infusions, and (b) infusions should be stopped every 24–28 hours to allow recovery of function. Concurrent steroid administration may increase likelihood of this complication.
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TABLE 2.6. Reversal of Nondepolarizing Neuromuscular Blocking Drugs
Drug Dosage Onset/Duration Comments
Neostigmine-Glycopyrrolate 25–75 µg/kg
5–15 µg/kg
Onset: 3–8 min
Duration: 40–60 min
 
Pyridostigmine-Glycopyrrolate 100–300 µg/kg
5–15 µg/kg
Onset: 2–5 min
Duration: 90 min
Must be used to reverse long-acting neuromuscular blocking agents (i.e., doxacurium, pancuronium)
Edrophonium-Atropine 500–1000 µg/kg
10 µg/kg
Onset: 30–60 s
Duration: 10 min
Rapid onset; not useful for deep blockade
Use lower doses to reverse minimal blockade, maximum doses for deep blockade. The anticholinergic agent must be given to block undesired muscarinic effects of anticholinesterase drug; this applies even when the patient has a baseline tachycardia. Reversal of neuromuscular blockade is associated with a high incidence of transient arrhythmias.
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TABLE 2.7. Topical Anesthetics
Agent Concentration Use Comments
Cocaine 4% Topical to nares and nasopharynx prior to nasal intubation Vasoconstriction
Controlled substance
Lidocaine 1–4% Solution: oropharynx, tracheobronchial tree
Viscous: nasal and oral pharynx
Vasodilating, therefore must be used in conjunction with a vasoconstrictor during nasal intubation
Dilute solutions (1–2%) may be nebulized and inhaled to provide anesthesia for bronchoscopy
Total dose should be less than 400 mg
Large doses have been associated with methemoglobinemia
Eutectic Mixture Lidocaine and Prilocaine (EMLA)   Apply to skin for 1 h prior to procedures involving skin puncture Application to inflamed skin may increase absorption
Ineffective when rubbed into skin
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TABLE 2.8. Local Anesthetics for Infiltration and Nerve Blocks
Drug Concentration (Maximum Dose) Use Features
Lidocaine 0.5% (400 mg without epinephrine; 500 mg with epinephrine) Local infiltration Relatively short duration
Epinephrine prolongs block and decreases peak levels
Lidocaine 1–2% (400 mg without epinephrine; 500 mg with epinephrine) Nerve blocks Short duration
Epinephrine prolongs block and decreases peak levels
Bupivicaine 0.25–0.75% Nerve blocks
Epidural
Long duration, slow onset
Addition of epinephrine may not prolong block but may decrease systemic absorption
Avoid epinephrine-containing solutions in areas supplied by end-arteries (e.g., fingers, toes, penis). Nerve blocks should be performed by personnel trained in the procedures and in treatment of local anesthetic toxicity.
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TABLE 2.9. Comparison of Narcotic Analgesics
Drug Route/Equivalencea Onset of Action (min) Peak Analgesic Effect (min) Duration of Action (h)
Alfentanil IM: 1 mg IV: 1–2 IV: 1–2 IV: 0.25
Codeine PO: 200 mg PO: 30–45 PO: 60–120 PO: 4–6
  IM: 120 mg IM: 10–30 IM: 30–60 IM: 4
Fentanyl IM: 0.1 mg IV: <1 IV: 1–2 IV: 0.5–1
    IM: 7–5 IM: N/A IM: 1–2
Hydromor-phone PO: 7.5 mg PO: 30 PO: 90–120 PO: 4
  IM: 1.5 mg IM: 30–60 IM: 4–5  
    IV: 10–15 IV: <20 IV: 2–3
Levorphanol PO: 4 mg PO: 10–60 PO: 90–120 PO: 4–5
  IM: 2 mg IM: N/A IM: 30–60 IM: 4–5
      IV: <20 IV: 4–5
Meperidine PO: 300 mg PO: 15 PO: 60–90 PO: 2–4
  IM: 75 mg IM: 10–15 IM: 60–120 IM: 2–4
    IV: 1 IV: 15–30 IV: 2–4
Methadone PO: 20 mg PO: 30–60 PO: 90–120 PO: 4–6b
  IM: 10 mg IM: 10–20 IM: 60–120 IM: 4–5b
    IV: N/A IV: 15–30 IV: 3–4b
Morphine PO: 60 mg PO: 15–60 PO: 60–120 PO: 4–5
  IM: 10 mg IM: 10–30 IM: 30–60 IM: 4–5
    IV: <1 IV: 20 IV: 4–5
Oxycodone PO: 30 mg PO: 15–30 PO: 60 PO: 4–6
Propoxyphene Toxicc PO: 15–60 PO: 120 PO: 4–6
Remifentanild IV: 0.05–0.15 µg/kg IV: <1 IV: <1 IV: 3–4 min
Sufentanil IM: 0.01–0.02 mg IV: <1 IV: 1–2 IV: 0.25–1
IM, intramuscular; IV, intravenous; PO, by mouth
aDose in mg therapeutically equivalent to morphine 10 mg IM. IM doses are used to specify equivalent doses but are not recommended when IV access is available.
bIncreases with repetitive dosing due to accumulation of drug and/or metabolites.
cDose equivalent to 10 mg of morphine would be too toxic to administer.
dRemifentanil is suitable for IV infusion only.
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TABLE 2.10. Parenteral Analgesic Agents
Drug Bolus Dosage Continuous Infusion Comments
Alfentanil 10–25 µg/kg 0.5–3 µg/kg/min Safe to use in renal failure because lack of active metabolites
Codeine 15–60 mg N/A Usually effective for mild to moderate pain
Recommended in renal failure
Fentanyl 25–50 µg 50–100 µg/h Slows heart rate
Chest wall rigidity can occur
Increased half-life with continuous infusions
Hydromor- phone 1–4 mg N/A Reserved for patients who are tolerant to and are receiving high doses of opiates
Recommended in renal failure
Ketorolac 15–60 mg IV followed by 15–30 mg IV q6h   Parenteral NSAID; lower doses in elderly patients; especially useful for orthopedic pain; reversible platelet dysfunction; associated with acute renal failure when given for more than 5 d
Advantage over opioids: no hemodynamic effects, respiratory depression, or ileus
Combined IV/IM/PO therapy limited to 5 d
Levorphanol 2 mg N/A Optimal IV dose has not been established
Avoid in patients with increased intracranial pressure, asthma, acute alcoholism
Meperidine 25–100 mg 5–35 mg/h Highly lipid soluble
Accumulation of neurotoxic (convulsant) normeperidine metabolite in renal failure and in patients receiving large cumulative doses
Avoid in patients receiving MAOI
Methadone 2.5–10 mg N/A Duration of action and half-life increases with repetitive dosing
With repetitive doses, the dose should be lowered or the interval lengthened to avoid excessive narcosis
Morphine 2–10 mg 2–5 mg/h Less lipid soluble versus fentanyl
Histamine release with bolus doses may cause hypotension or, rarely, bronchospasm
Active metabolite morphine-6-glucuronide accumulates in renal failure, producing enhanced narcosis
Remifentanil 0.05 µg/kg 0.0125–0.025 µg/kg/min Ultrashort action may limit its use for pain
Bolus doses are not recommended to treat postoperative pain
IV tubing must be cleared after administration to avoid inadvertent bolus dose
Sufentanil 0.2–0.6 µg/kg 0.01–0.05 µg/kg/min May allow for volume reduction in patients receiving large doses of continuous infusion narcotics
IV, intravenous; MAOI, monoamine oxidase inhibitor; NSAID, nonsteroidal anti-inflammatory drug
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TABLE 2.11. Patient-Controlled Analgesia (PCA) Guidelines
  Morphine Fentanyl Hydromorphone
Standard dilution 2 mg/mL 20 µg/mL 0.5 mg/mL
Demand dose 1 mg 20 µg 0.2 mg
Initial lockout 6 min 6 min 6 min
Initial basal rate 0 0 0
Considerations Generally, opioid of choice unless patient has renal insufficiency or is intolerant to morphine: nausea, vomiting, pruritus Less accumulation may result in less confusion in elderly patients; preferred over morphine in patients with renal insufficiency to avoid accumulation of morphine metabolites  
For patients who report pain on PCA, first assess the frequency of self-dosing. If the patient is not self-dosing at least 3 times per hour, encourage him or her to dose more often. Failing that, give the patient a bolus dose (2–5 mg of morphine or equivalent) and increase the demand dose to 1.5 or 2 mg of morphine or equivalent. Finally, consider an adjuvant drug (ketorolac) or a low basal rate (0.5 mg/h of morphine or equivalent).
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TABLE 2.12. Oral Analgesic Agents
Agent Onset/Duration Dosage Comments
Narcotic
Codeine Onset: 15–30 min
Duration: 4–6 h
30–60 mg q4h  
Codeine with acetaminophen 300 mg Onset: 15–30 min
Duration: 4–6 h
1–2 tablets q4h Available with codeine 7.5 mg, 15 mg, 30 mg, or 60 mg
Oxycodone 5 mg Onset: 15–30 min
Duration: 4–6 h
5–10 mg q4h Sustained release preparation, Oxycontin, has been associated with illegal abuse and diversion; deaths have resulted when the pills have been crushed and the powder inhaled
Oxycodone 5 mg with acetamino- phen 325 mg Onset: 15–30 min
Duration: 4–6 h
1–2 tablets q4h  
Oxycodone HCl 4.5 mg plus oxycodone terephthalate 0.38 mg with aspirin 325 mg Onset: 15–30 min
Duration: 4–6 h
1–2 tablets q4h  
Propoxyphene napsylate 50 or 100 mg with acetaminophen 325 mg Onset: 15–60 min
Duration: 4–6 h
1–2 tablets q4h  
Propoxyphene 32 or 65 mg Onset: 15–60 min
Duration: 4–6 h
32–65 mg q4h  
Non-narcotic
Acetaminophen Onset: 0.5–1 h
Duration: 3–6 h
325–650 mg q4h  
Aspirin Onset: 0.5 h
Duration: 3–6 h
325–650 mg q4h  
Choline magnesium salicylate Onset: 30–60 min
Duration: N/A
1000–2000 mg bid 500 mg = ASA 650 mg
May monitor with salicylate levels
Does not affect platelet aggregation
Available as a liquid 500 mg/5 ml
Ibuprofen Onset: 0.5 h
Duration: 3–6 h
400–800 mg tid-qid Reversible effect on platelet aggregation
Available as a liquid 100 mg/5 ml
Ketorolac Onset: 30–60 min
Duration: 4–6 h
10 mg q4–6h Reversible platelet effect
Reduce dose in elderly patients
Maximum oral dose 40 mg/day
Indicated only as continuation therapy to parenteral ketorolac up to a maximum duration of 5 d of combined IV/IM/PO administration
Tramadol Onset: 1 h
Duration: 3–6 h
50–100 mg q4–6h Reduce dose in patients with renal or liver failure
IV, intravenous; IM, intramuscular, PO, by mouth
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TABLE 2.13. Oral Sedative-Hypnotic Agents
Agent Onset Usual Dosage Half-Life Comments
Benzodiazepines
Alprazolam Intermediate Sedative: 0.25–0.5 mg PO tid 12–15 h No active metabolites
Diazepam Fast Sedative: 2–10 mg PO bid-qid Pre-op medication: 5–10 mg PO 1 h before procedure 20–200 h Active metabolites accumulate with chronic dosing and contribute to pharmacologic effect
Available in a liquid dosage form (1 mg/ml and 5 mg/ml)
Lorazepam Intermediate Sedative: 0.5–3 mg PO bid-tid 10–20 h No active metabolites
Safe to use in liver disease
    Hypnotic: 0.5–4 mg PO qhs   Available in a liquid dosage form (2 mg/ml)
    Pre-op medication: 1–4 mg PO 1–2 h before procedure   Amnesia may be produced for as long as 4–6 h without excessive sedation when lorazepam is used as a pre-op medication
Midazolam Fast Pre-op medication: 0.5–0.75 mg/kg PO 1–2 h before procedure 3–6 h Use high potency 5 mg/ml injectable form and dilute in 3–5 ml of fruit juice
Oxazepam Slow Sedative: 10–30 mg PO tid-qid
Hypnotic: 10–30 mg PO qhs
5–20 h No active metabolites
Temazepam Intermediate Sedative: N/A
Hypnotic: 7.5–30 mg PO qhs
10–17 h No active metabolites
Barbiturates
Pentobar- bital Fast Sedative: N/A
Hypnotic: 100 mg PO qhs
Pre-op medication: 100 mg PO 1–2 h before procedure
22 h Geriatric or debilitated patients may react to usual doses with excitement, confusion, or mental depression; lower doses may be required in these patients
Secobarbital Fast Sedative: N/A
Hypnotic: 100 mg PO qhs
Pre-op medication: 200–300 mg PO 1–2 h before procedure
28 h Geriatric or debilitated patients may react to usual doses with excitement, confusion, or mental depression; lower doses may be required in these patients
Other agents
Chloralhy-drate Intermediate Sedative: 250 mg PO tid after meals
Hypnotic:500–1000 mg PO qhs
Pre-op medication: 25–75 mg/kg up to 2 g PO 1 h before procedure
8 h TCE Active metabolite TCE
Available in liquid (10 mg/ml) and suppository (500 mg) dosage forms
Diphenhydramine Slow Hypnotic: 25–50 mg PO qhs 1–4 h Available in a liquid dosage form (12.5 mg/5 ml)
Half-life is prolonged in patients with liver disease
Eszopic-lone Fast Sedative: N/A
Hypnotic: 1–3 mg PO qhs
  Reduce to 1 mg in elderly patients, patients receiving CYP3A4 inhibitors and patients with severe hepatic disease
Zaleplon Fast Sedative: N/A
Hypnotic: 5–10 mg PO qhs
1 h The initial dose should be reduced to 5 mg in elderly and in patients with liver disease
Zolpidem Fast Sedative: N/A
Hypnotic: 5–10 mg PO qhs
2.5 h No active metabolites
An initial dose of 5 mg should be used in patients with liver disease
Amitripty-line Slow 25–100 mg qhs   Sedating tricyclic antidepressant
Contraindicated in acute recovery phase of myocardial infarction
Quetiapine Intermediate 25–100 mg qhs   Sedating dibenzothiazepine antiphychotic
May result in orthostatic hypotension or tachyarrhythmias
Anticholinergic effects (dry mouth, constipation)
PO, by mouth; TCE, trichloroethanol
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TABLE 2.14. Malignant Hyperthermia—Therapy
Typical Presentation
Setting: Intraoperative or early postoperative.
Clinical: Tachycardia, tachypnea, ventricular arrhythmias, muscle rigidity, fever
Laboratory: Combined respiratory and metabolic acidosis, hyperkalemia, hypercalcemia, myoglobinuria, elevation in creatine phosphokinase.
Protocol for treatment
Discontinue triggering drug (succinylcholine, inhalational anesthetic).
Hyperventilate with 100% oxygen.
Dantrolene 2.5 mg/kg IV repeated every 5–10 min as dictated by the clinical situation. Although 10 mg/kg is often reported as a maximum total dose, more dantrolene may be needed.
Follow usual guidelines for treatment of metabolic acidosis, hyperkalemia (calcium has not been investigated in this setting), hyperthermia (external ice, gastric lavage), disseminated intravascular coagulation, prevention and treatment of myoglobinuric renal failure.
Procainamide as needed for arrhythmias refractory to general measures. Avoid calcium channel blockers in conjunction with dantrolene.
For health care providers having questions on patient management, the Malignant Hyperthermia Association of the United States operates a hot line: 1-800-644-9737.
IV, intravenous
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TABLE 2.15. Neuroleptic Malignant Syndrome
Typical Presentation
Setting: Most cases within 30 days of antipsychotic (neuroleptic) drug administration (incidence ~0.07–0.4%) or withdrawal of dopamine agonist (e.g., levodopa, amantadine).
Viewed as extreme extrapyramidal adverse effect versus idiosyncratic drug reaction related to antidopaminergic effects in central nervous system. Increased risk in highly agitated restrained patient.
Clinical Presentation: Hyperthermia caused by muscle rigidity, vasoconstriction, and possibly central nervous system effect. Dehydration, mental status changes (obtundation), autonomic instability (tachycardia, oscillations in blood pressure).
Laboratory: Elevated serum creatine phosphokinase, leukocytosis, metabolic acidosis.
Protocol for treatment
Discontinue antipsychotics if muscle rigidity impairs breathing or swallowing.
Control temperature (cooling blankets, ice baths, antipyretics; avoid NSAID because of renal effects), correct fluid and electrolyte disturbances.
Anticholinergics (if temperature <38.9°C): benztropine (up to 8 mg/d, PO, IM, IV), may worsen hyperthermia.
Dopamine agonists (if temperature >38.9°C): amantadine 200–300 mg/d PO, bromocriptine 7.5–75 mg/day PO, carbidopa/levodopa 300–800 mg/d PO.
Dantrolene 4–8 mg/kg/d PO/IV.
IV, intravenous; IM, intramuscular, PO, by mouth