What is the recommended dose and administration guidelines for Dexamethasone (corticosteroid) given intramuscularly (IM)?

Dexamethasone Intramuscular Dosing

Dexamethasone IM dosing ranges from 0.5 mg/day to 9 mg/day for most indications, with higher doses (10-20 mg) used for specific severe conditions like cytokine release syndrome, chemotherapy-induced emesis, and cerebral edema. 1

General Dosing Principles

• The FDA-approved dosage range is 0.5 to 9 mg/day IM, with the parenteral dose typically being one-third to one-half of the oral equivalent given every 12 hours 1
• In life-threatening situations, doses exceeding usual ranges may be justified and can be multiples of standard oral doses 1
• Dexamethasone has equivalent bioavailability between oral and IV/IM routes (1:1 conversion), so 40 mg IV = 40 mg IM = 40 mg oral 2

Condition-Specific IM Dosing

Cytokine Release Syndrome (CRS)

• Grade 1 CRS: 10 mg IM/IV every 24 hours 3
• Grade 2 CRS: 10 mg IV every 12-24 hours for persistent refractory hypotension 3
• Grade 3 CRS: 10 mg IV every 6 hours 4, 3
• Grade 4 CRS: 10 mg IV every 6 hours, escalating to methylprednisolone 1000 mg/day if refractory 4, 3

Cerebral Edema

• Initial dose: 10 mg IV, followed by 4 mg IM every 6 hours until maximum response 1
• This regimen may continue for several days postoperatively in brain surgery patients 1
• Transition to oral dexamethasone 1-3 mg three times daily as soon as possible, then taper over 5-7 days 1

Chemotherapy-Induced Nausea/Vomiting

• High emetogenic risk chemotherapy: 20 mg once daily (with 5-HT3 antagonists) 4
• Moderate emetogenic risk chemotherapy: 8 mg once daily before chemotherapy 4
• Multiday chemotherapy regimens: Administer once daily for every day of moderately or highly emetogenic chemotherapy, plus 2-3 days after completion 4
• When used with aprepitant, reduce to 12 mg on day of chemotherapy and 8 mg daily on days 2-4 4

Shock (Unresponsive)

• Reported regimens range from 1-6 mg/kg as a single IV injection to 40 mg initially, followed by repeat injections every 2-6 hours while shock persists 1

Pediatric Asthma Exacerbations

• Approximately 1.7 mg/kg IM as a single dose (equivalent to 2 mg/kg/day oral prednisone for 5 days) 5
• A single IM injection is as effective as a 5-day oral prednisone course for mild-moderate outpatient asthma exacerbations 5
• The smallest effective dose should be used in children, preferably orally, approximating 0.2 mg/kg/24 hours in divided doses 1

Croup

• 0.6 mg/kg IM as a single dose 6
• This single injection is beneficial in acute spasmodic croup and results in shorter hospital stays 6

Intra-articular and Soft Tissue Injections

• Large joints: 2-4 mg 1
• Small joints: 0.8-1 mg 1
• Soft tissue and bursal injections: 2-4 mg 1
• Ganglia: 1-2 mg 1
• Tendon sheaths: 0.4-1 mg 1
• Frequency ranges from once every 3-5 days to once every 2-3 weeks 1

Critical Safety Considerations

Adrenal Suppression

• Adrenal suppression occurs with doses as low as 1-4 mg but resolves within 48 hours of discontinuation 3
• After long-term therapy, withdraw gradually rather than abruptly 1

Antifungal Prophylaxis

• Strongly consider antifungal prophylaxis in patients receiving prolonged steroids, especially for immunotherapy toxicities 3

Administration Technique

• IM injections cause no significant complications when properly administered 5
• The IM route offers reproducible drug input with minimal stress and 86% bioavailability 7
• Absorption is rapid after IM dosing with an absorption half-life of approximately 14 minutes 7

Important Caveats

• Do not add dexamethasone when the chemotherapy regimen already includes a corticosteroid 4
• Avoid steroids when using regimens containing interleukin-2 (aldesleukin) or interferon 4
• Frequent intra-articular injection may cause joint tissue damage 1
• Injection into intervertebral joints should not be attempted, and hip joint injection is not recommended as an office procedure 1
• Constant monitoring is needed for dosage adjustments based on clinical response, disease remissions/exacerbations, and patient exposure to stressful situations 1