streptomycin

Brand: Streptomycin Sulfate

⚠ BBW TDM Required Prototype: gentamicin
Drug Class: aminoglycoside antibiotic
Drug Family: antibiotic
Subclass: first aminoglycoside; anti-tuberculosis agent
Organ Systems: infectious-disease

Mechanism of Action

Binds irreversibly to the 30S ribosomal subunit, causing misreading of mRNA; particularly active against Mycobacterium tuberculosis and some gram-negative organisms; the first aminoglycoside and first antibiotic effective against tuberculosis.

30S ribosomal subunit

Indications

  • tuberculosis (as part of combination therapy — second-line)
  • enterococcal endocarditis (in combination with penicillin)
  • brucellosis
  • tularemia
  • plague (Yersinia pestis)

Contraindications

  • aminoglycoside hypersensitivity
  • pregnancy (high ototoxicity risk)

Adverse Effects

Common

  • vestibular toxicity (dizziness, nystagmus, ataxia)
  • nephrotoxicity
  • injection site pain

Serious

  • irreversible vestibular toxicity
  • irreversible hearing loss (less common than vestibular toxicity)
  • neuromuscular blockade
  • fetal ototoxicity

Pharmacokinetics (ADME)

Absorption IM only (not absorbed orally)
Distribution extracellular distribution; poor CNS penetration
Metabolism not metabolized
Excretion renal (unchanged)
Half-life 2.5 hours (normal renal function)
Onset 30–90 minutes (IM)
Peak 1–2 hours
Duration 24 hours
Protein Binding 35%
Vd low

Drug Interactions

Drug / Agent Mechanism Severity
loop diuretics additive ototoxicity major
other nephrotoxins additive nephrotoxicity major

Nursing Considerations

  1. Administer IM only; no IV formulation is commercially available in most countries.
  2. Monitor vestibular function (balance, gait, dizziness) regularly — vestibular toxicity from streptomycin is more common than cochlear toxicity.
  3. Monitor BUN and SCr; reduce dose or extend interval in renal impairment.
  4. In tuberculosis regimens, streptomycin is given as part of standardized combinations; counsel patients on the importance of adherence to prevent resistance.

Clinical Pearls

  • Streptomycin has a distinctive toxicity profile: vestibular toxicity (causing dizziness, vertigo, and nystagmus) is more common than the cochlear ototoxicity seen with gentamicin and tobramycin.
  • For enterococcal endocarditis, synergy between streptomycin (or gentamicin) and a cell-wall agent (penicillin or ampicillin) is essential; aminoglycoside high-level resistance (MIC >2000 mcg/mL) eliminates this synergy.

Safety Profile

Pregnancy use-with-caution
Lactation use-with-caution
Renal Adjustment Required
Hepatic Adjustment Not required
TDM Required