1. Clinical Overview
Streptomycin is an aminoglycoside antibiotic derived from *Streptomyces griseus*. It is a first-line bactericidal agent primarily used in the treatment of tuberculosis (TB) and other mycobacterial infections. It is a cornerstone of anti-tubercular therapy in India, particularly for drug-resistant TB and as part of the standard regimen for new cases. Its use is strictly controlled due to significant ototoxicity and nephrotoxicity, requiring intramuscular (IM) administration and careful monitoring.
| Onset | Duration | Bioavailability |
|---|---|---|
| Peak serum concentrations are reached within 1-2 hours after intramuscular injection. | The bactericidal effect is concentration-dependent and has a significant post-antibiotic effect, allowing for once-daily dosing in many regimens. Serum levels remain effective for 12-24 hours. | Approximately 84-88% after intramuscular injection. It is not absorbed from the gastrointestinal tract. |
2. Mechanism of Action
Streptomycin binds irreversibly to the 30S subunit of the bacterial ribosome at specific proteins (S12) and 16S rRNA. This binding interferes with the initiation complex of peptide formation, causes misreading of the mRNA template, and leads to the incorporation of incorrect amino acids into the growing polypeptide chain. The result is inhibition of protein synthesis and a bactericidal effect.
3. Indications & Uses
- Pulmonary Tuberculosis (as part of DOTS or other regimens under NTEP)
- Extrapulmonary Tuberculosis (e.g., TB lymphadenitis, skeletal TB)
- Multidrug-Resistant Tuberculosis (MDR-TB)
- Plague (Yersinia pestis infection)
- Tularaemia
- Brucellosis (in combination with doxycycline or tetracycline)
4. Dosage & Administration
Adult Dosage: Tuberculosis: 15 mg/kg (max 1 gm) intramuscularly once daily or 750 mg - 1 gm 5-7 times per week as per NTEP guidelines. For other infections: 1-2 gm/day in divided doses (every 6-12 hours).
Administration: For IM use only. Deep intramuscular injection into a large muscle mass (gluteus maximus or lateral thigh). Rotate injection sites. Reconstitute the 0.75gm vial with 3-5 ml of Sterile Water for Injection or 0.9% Sodium Chloride. Shake gently to dissolve. Administer immediately or store refrigerated. DO NOT ADMINISTER INTRAVENOUSLY BOLUS.
5. Side Effects
Common side effects may include:
- Pain, induration, or sterile abscess at injection site
- Numbness, tingling, or burning sensations (paresthesia) around mouth
- Rash, fever, eosinophilia (hypersensitivity)
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Other Aminoglycosides (Gentamicin, Amikacin) | Additive ototoxicity and nephrotoxicity | Major |
| Loop Diuretics (Furosemide, Ethacrynic acid) | Additive ototoxicity, especially when given IV | Major |
| Vancomycin | Additive nephrotoxicity and ototoxicity | Major |
| Neuromuscular Blocking Agents (Succinylcholine, Tubocurarine) | Enhanced and prolonged neuromuscular blockade, risk of respiratory arrest | Major |
| Cephalosporins (especially 1st gen like Cefalotin) | Potential additive nephrotoxicity | Moderate |
| Penicillins (in vitro) | Chemical inactivation if mixed in same IV line/syringe | Moderate |
7. Patient Counselling
- DO report any ringing/buzzing in ears, dizziness, feeling of fullness in ears, or unsteadiness IMMEDIATELY.
- DO maintain adequate fluid intake unless advised otherwise by your doctor.
- DO keep all appointments for hearing tests (audiometry) and blood tests (creatinine).
- DO rotate injection sites as instructed.
- DO NOT stop the injection without consulting your TB treatment supervisor/doctor.
- DO NOT take any other medicines (including OTC painkillers like NSAIDs) without informing your doctor.
8. Toxicology & Storage
Overdose: Manifestations of overdose include severe ototoxicity (deafness, vertigo, tinnitus), nephrotoxicity (acute renal failure with oliguria), and neuromuscular blockade (muscle weakness, respiratory depression or arrest).
Storage: Store unopened vials at controlled room temperature (15-25°C), protected from light. After reconstitution with Sterile Water for Injection, the solution is stable for 24-48 hours when stored in a refrigerator (2-8°C). Do not freeze. Discard any unused portion after this time. Keep out of reach of children.