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 11 - Allergy
Chapter 11
Allergy
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TABLE 11.1. Anaphylaxis and Contrast Dye Reactionsa—Prophylaxis
Agent Dosage Time Prior to Exposure
Prednisone or Hydrocortisone 50 mg PO
100 mg IV
13 h, 7 h, and 1 h prior to exposure
Diphenhydramine 50 mg PO or IV 13 h, 7 h, and 1 h prior to exposure
H2-blockerb See below 13 h and 1 h prior to exposure
Ephedrine (optional) 25 mg PO 1 h prior to exposure
IV, intravenous; PO, by mouth
Note: Consider for patients with prior history of dye reaction; may also consider use of nonionic contrast material
aThis regimen also appropriate for other prophylactic situations.
bRanitidine: 150 mg PO or 50 mg IV
Famotidine: 20 mg PO/IV
Cimetidine: 300 mg PO/IV
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TABLE 11.2. Anaphylaxis—Therapy
Situation Intervention Comments
Systemic anaphylaxis Epinephrine 1:1,000, 0.3 cc SC, repeat at 5–10 min intervals
Diphenhydramine 25–100 mg IV
H2-blockera
Hydrocortisone 100–250 mg IV q6h
Repeat doses of diphenhydramine may be required for symptom relief
Special Problems
Upper airway obstruction Nebulized racemic epinephrine, 0.3 ml diluted in 3 ml 0.9% NaCl Administer oxygen; consider tracheal intubation and mechanical ventilation
Bronchospasm Epinephrine 1:1,000, 0.3–0.5 ml SC, may repeat at 5–10 min intervals, or
Albuterol, 1–2 puffs metered dose inhaler or 2.5–5 mg nebulized in 2–3 ml 0.9% NaCl, or
Aminophylline, 6 mg/kg IV initially (see Table 4.4)
With severe bronchospasm or hypotension, consider epinephrine, 1:10,000, 0.5–1.0 ml IV (rather than SC)
Shock Volume resuscitation with 0.9% NaCl ≥500 ml rapidly, with or without vasopressors
Dopamine 5–20 µg/kg/min, titrated to blood pressure, or
Norepinephrine, 2 µg/min, titrated to blood pressure
Patients on β-blockers who are hypotensive may also be treated with glucagon, 1 mg IV
IV, intravenous; SC, subcutaneous
aRanitidine: 50 mg IV
Famotidine: 20 mg IV
Cimetidine: 300 mg IV
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TABLE 11.3. Desensitization Procedure for Beta-lactam and Other Antibiotics
For patients with severe or life-threatening infections and a history of previous significant allergic reactions to an essential antibiotic (e.g., a history of wheezing, hypotension, an-gioedema, or other symptoms and signs of systemic anaphylaxis on exposure to the antibiotic or class). This may be documented with skin testing to penicillin if reagents are available. For other classes of antibiotics, the decision to desensitize is based on the clinical history.
  1. The procedure should be carried out in a monitored setting with a physician available.
  2. A secure IV line should be established.
  3. Epinephrine, diphenhydramine, parenteral glucocorticosteroids should be immediately available for acute anaphylactic reactions (see Table 11.2).
  4. Six serial 10-fold dilutions of the desired antibiotic dose should be prepared each in 20 ml bags or syringes.
  5. Each dose from the most dilute to the least dilute should be administered intravenously over 20 minutes (1 ml/min).
  6. A physician should examine the patient prior to each dose.
Example: Ceftriaxone
   2 mcg/20 ml over 20 minutes
   20 mcg/20 ml over 20 minutes
   200 mcg/20 ml over 20 minutes
   2 mg/20 ml over 20 minutes
   20 mg/20 ml over 20 minutes
   200 mg/20 ml over 20 minutes
   2 gm/20 ml (full dose) over 20 minutes
  • In the absence of an allergic reaction, the standard dose of the antibiotic may be administered after approximately 2 hours.
  • If a mild to moderate reaction such as flushing, wheezing, or chest tightness occurs, the infusion should be stopped and the subject treated with antihistamines, epinephrine, or both.
  • When the patient's symptoms/signs have resolved, the infusion may be repeated or resumed at 0.5 ml/min.
  • If a severe reaction occurs, the infusion should be stopped and the line aspirated to remove any residual antibiotic. The subject should be treated as described in the anaphylaxis therapy protocol (Table 11.2) and the desensitization effort discontinued.
  • When there is a need to provide immediate antibiotic coverage because of severe infection, an alternative antibiotic should be administered for at least one dose prior to the desensitization procedure.
  • The desensitization procedure should limit or prevent acute allergic reactions to the antibiotic during the initiation of the antibiotic but will need to be reimplemented if a time period greater than 48 hours elapses between doses of therapy.