Makindo Medical Notes

💊 About

Streptomycin is an injectable aminoglycoside antibiotic with activity against Mycobacterium tuberculosis and certain Gram-negative bacteria. It was one of the earliest effective anti-TB agents and remains useful in drug-resistant tuberculosis and rare infections such as bubonic plague. Always 🔗 check the BNF entry here for the latest dosing, cautions, and interactions.

🧠 Mode of Action

• Belongs to the aminoglycoside class of antibiotics.
• Binds to the 30S ribosomal subunit of bacteria, inhibiting initiation of protein synthesis.
• Causes misreading of mRNA and production of non-functional proteins — leading to bacterial death (bactericidal).
• Active against Mycobacterium tuberculosis and certain Gram-negative bacilli (e.g. Yersinia pestis).

📋 Indications

• 💀 Bubonic plague (Yersinia pestis infection).
• 🦠 Drug-resistant or multidrug-resistant tuberculosis (MDR-TB) as part of combination therapy.
• Occasionally used for brucellosis or endocarditis in specialist settings.

💉 Dose

Note: Dose should be reduced in patients aged >40 years, underweight, or with renal impairment.

⚠️ Interactions

• Concurrent use with other nephrotoxic or ototoxic drugs (e.g. vancomycin, loop diuretics, amphotericin B, cisplatin) increases toxicity risk.
• Avoid co-administration with other aminoglycosides.
• Always check the BNF for full interaction details.

🚧 Cautions

• Use with extreme caution in myasthenia gravis — may exacerbate muscle weakness.
• Reduce dose in those under 50 kg or over 40 years old.
• Renal impairment: careful dose adjustment and drug level monitoring required.
• Hydration and avoidance of other nephrotoxins are critical to reduce renal injury.

⛔ Contraindications

• Known hypersensitivity to aminoglycosides.
• Pregnancy (risk of fetal ototoxicity).
• Severe renal impairment unless under expert supervision.

🧪 Monitoring

• Peak (1-hour post-dose): 15–40 mg/L.
• Trough (pre-dose): <5 mg/L (preferably <1 mg/L in renal impairment or in those >50 years).
• Monitor renal function (U&E), auditory function, and vestibular symptoms regularly.

💥 Side Effects

• 🎧 Ototoxicity: tinnitus, vertigo, or hearing loss (may be irreversible).
• 💧 Nephrotoxicity: usually reversible if detected early.
• 🤢 Nausea, vomiting, and injection-site pain.
• 🩸 Rare: skin rash, eosinophilia, or hypersensitivity reactions.

📚 References

• BNF: Streptomycin
• WHO Consolidated Guidelines on Drug-Resistant Tuberculosis, 2023.
• Public Health England (PHE) TB Drug Manual.