IM Dexamethasone for Severe Strep Throat
A single dose of intramuscular dexamethasone (10 mg for adults, 0.6 mg/kg up to 10 mg for children) is reasonable as adjunctive therapy for severe strep throat already on antibiotics, providing faster pain relief without increasing serious adverse effects.
Evidence Supporting Dexamethasone Use
The most recent high-quality evidence demonstrates that corticosteroids provide meaningful symptomatic benefit in acute pharyngitis:
Patients receiving a single low-dose corticosteroid are twice as likely to experience pain relief at 24 hours (relative risk 2.2) and 1.5 times more likely to have complete pain resolution at 48 hours compared to placebo 1
The mean time to onset of pain relief occurs 4.8 hours earlier with corticosteroids, and complete pain resolution occurs 11.1 hours earlier than placebo 1
Absolute pain reduction at 24 hours is significantly greater with corticosteroids (mean difference 1.3 points on a 0-10 visual analog scale) 1
Specific Dosing Recommendations
For adults: A single oral dose of 10 mg dexamethasone is the most commonly studied and effective regimen 2, 1
For children (ages 4-21): 0.6 mg/kg oral dexamethasone (maximum 10 mg) provides significantly faster pain relief, especially in severe or exudative group A streptococcal pharyngitis 3
Children receiving 3 daily doses of dexamethasone showed more rapid improvement in general condition, activity level, and throat pain resolution compared to single-dose or placebo 4
However, the single-dose regimen remains most practical and is supported by the strongest evidence 1
Route of Administration: IM vs Oral
While the question asks about IM administration, the highest quality evidence exclusively studied oral dexamethasone 2, 1. IM dexamethasone at the same dose (10 mg for adults, 0.6 mg/kg for children) would be expected to have equivalent or potentially faster absorption, making it a reasonable alternative when:
- The patient has severe odynophagia limiting oral intake
- Compliance with oral medication is uncertain
- Immediate symptom relief is prioritized
Critical Safety Considerations
Nine of 10 trials assessed adverse events and found no increase in serious complications with corticosteroids 1
Six studies reported no adverse effects, and three reported few adverse events with similar incidence in both treatment and placebo groups 1
Corticosteroids are NOT recommended as routine adjunctive therapy by IDSA guidelines 5, but this recommendation predates the most recent high-quality meta-analysis 1
Avoid in patients with diabetes or endocrine disorders already receiving exogenous steroids 6
When Dexamethasone Provides Maximum Benefit
The evidence suggests dexamethasone is most beneficial for:
- Severe pharyngitis with significant pain limiting oral intake 3
- Exudative group A streptococcal pharyngitis where inflammation is most pronounced 3
- Patients requiring faster return to work or normal activities 1
Essential Antibiotic Therapy Must Continue
Dexamethasone is purely adjunctive for symptom relief and does NOT replace the need for appropriate antibiotic therapy:
Penicillin V 500 mg orally twice daily for 10 days remains the treatment of choice for confirmed strep throat 7
The full 10-day antibiotic course is essential to prevent acute rheumatic fever and suppurative complications 7
Antibiotics reduce acute rheumatic fever by more than two-thirds (RR 0.22) and significantly decrease suppurative complications including acute otitis media (RR 0.30) and peritonsillar abscess (RR 0.15) 8
Common Pitfalls to Avoid
Never use corticosteroids as monotherapy - antibiotics remain essential for preventing complications 7, 8
Do not prescribe multiple doses or prolonged courses - the evidence supports single-dose therapy only 1
Avoid aspirin in children due to Reye syndrome risk; use acetaminophen or ibuprofen instead 5, 7
Do not delay antibiotic initiation - corticosteroids provide symptomatic relief but do not treat the underlying infection 7