Understanding the 56 Injections for TB Treatment
The "56 injections" refers to the historical intensive phase of multidrug-resistant tuberculosis (MDR-TB) treatment, where injectable aminoglycosides (streptomycin, kanamycin, or amikacin) or capreomycin were administered daily for approximately 8 weeks (56 days) as part of the treatment regimen. 1
Historical Context of Injectable TB Treatment
Injectable agents were traditionally used during the intensive phase of MDR-TB treatment, typically administered daily for 4-8 months after culture conversion, which could total 56 or more injections in the initial weeks 1
This approach has been largely abandoned due to significant toxicity, particularly permanent hearing loss (9% of patients) and vestibular damage, along with the inconvenience of daily injections requiring healthcare worker administration 1
Current Treatment Paradigm Shift
The WHO and major guideline bodies now strongly recommend AGAINST the routine use of injectable agents for MDR-TB treatment, marking a dramatic shift away from the "56 injection" approach. 1
Modern All-Oral Regimens
The preferred treatment for MDR-TB is now the BPaLM regimen (bedaquiline, pretomanid, linezolid, and moxifloxacin) for 6 months, which achieved 89% favorable outcomes compared to 51% with standard injectable-containing regimens 1
All-oral regimens reduced grade 3/4 hearing loss from 9% to only 2% compared to injectable-containing regimens, while improving treatment success from 71% to 83% 1
At least five effective drugs should be used in the intensive phase of MDR-TB treatment, prioritizing newer oral agents (bedaquiline, linezolid, fluoroquinolones) over injectables 1, 2
Why the Change Occurred
Injectable agents caused severe, irreversible adverse effects including ototoxicity (hearing loss and vestibular dysfunction), nephrotoxicity, and required painful daily injections 1
Newer oral medications proved superior in efficacy and safety, with bedaquiline and linezolid demonstrating better outcomes without the toxicity burden 1
The 2018 individual patient data analysis of over 12,000 MDR-TB patients led to the WHO recommendation against injectable use in 2018-2019 1
Critical Clinical Implications
If you encounter a patient being treated with daily injectable TB medications, this represents outdated practice that should be reconsidered in favor of modern all-oral regimens 1, 2
The intensive phase duration is now defined as 5-7 months after culture conversion, not by the presence of an injectable agent 1
Total MDR-TB treatment duration is 15-21 months after culture conversion using modern all-oral regimens 2
Common Pitfall to Avoid
Do not confuse the historical "56 injections" approach with current standard of care—this outdated practice has been replaced by superior all-oral regimens that are more effective, safer, and better tolerated by patients. 1, 2