Why should intravenous (IV) dexamethasone be administered slowly and what unique symptom could the patient experience?

IV Dexamethasone Administration: Slow Infusion to Prevent Perineal Burning

IV dexamethasone should be administered slowly to prevent severe perineal burning and pain, which is a unique and distressing adverse effect that can occur with rapid administration.

Perineal Burning: A Unique Adverse Effect

• Intravenous dexamethasone administration can cause immediate (within 30 seconds) and severe perineal pain of shooting and burning character, particularly when given as a rapid bolus 1, 2
• This adverse effect is characterized by intense burning, itching, or tingling sensations specifically localized to the genital and perineal regions 3
• The symptoms are typically transient, lasting 2-4 minutes, but can be extremely distressing to patients 3
• Female patients appear to experience this adverse effect more frequently than males 4

Mechanism and Clinical Presentation

• The exact mechanism causing perineal burning is poorly understood but may be related to the phosphate ester in dexamethasone sodium phosphate formulations 4
• The pain is typically described by patients as:
  • Itching (62% of cases)
  • Burning (13% of cases)
  • Both itching and burning (25% of cases) 4
• In rare cases, the symptoms may spread beyond the perineal area to involve the entire trunk 3

Prevention Strategies

• Administer dexamethasone by slow intravenous infusion rather than rapid bolus 5
• Consider diluting dexamethasone in sodium chloride or dextrose solution before administration 5
• When used for PONV (postoperative nausea and vomiting) prophylaxis, consider administering after induction of anesthesia when the patient is unconscious 6
• Pretreatment with fentanyl (1 μg/kg) 5 minutes before dexamethasone administration has been shown to significantly reduce the incidence, severity, and duration of perineal pain 4

Potential Complications

• In rare cases, the intense pain from rapid dexamethasone administration has been associated with:
  • Acute hypertension
  • Shortness of breath
  • Pre-cordial pain
  • ECG changes (ST-segment depression)
  • Elevated troponin levels 6
• These complications appear to be related to catecholamine release triggered by the intense pain 6

Best Practices for Administration

• For antiemetic use in chemotherapy, dexamethasone should be administered as part of a standardized regimen, typically at doses of 8-12 mg IV 7
• When administering IV dexamethasone:
  • Give by slow infusion over several minutes
  • Consider dilution in compatible IV fluids
  • Monitor patients for signs of perineal discomfort during administration 5
  • If symptoms occur, slow or temporarily pause the infusion 7

Management if Perineal Burning Occurs

• Reassure the patient that the symptoms are temporary and typically resolve within minutes 3
• Slow or temporarily pause the infusion if symptoms are severe 7
• Consider administering fentanyl if symptoms are particularly distressing 4
• Document the reaction for future reference to guide subsequent administrations 2

By administering IV dexamethasone slowly and being aware of this unique adverse effect, clinicians can minimize patient discomfort while still providing the therapeutic benefits of this important medication.