A retrospective study on sequential desensitization-rechallenge for antituberculosis drug allergy

Area of Science:

• Clinical Medicine
• Pharmacology
• Infectious Diseases

Background:

• Antituberculosis (anti-TB) drug allergy complicates treatment, often requiring reintroduction of essential medications due to lack of alternatives.
• Managing multi-drug allergies in TB treatment is critical for patient outcomes.

Purpose of the Study:

• To evaluate the efficacy of a tailored sequential desensitization-rechallenge (D-R) protocol for patients with anti-TB drug allergies.
• To assess the safety and success rate of reintroducing anti-TB drugs through a structured D-R process.

Main Methods:

• Recruited patients with anti-TB drug allergies who underwent sequential D-R between 1997 and 2012.
• Administered anti-TB drugs starting at a low dose (1:6,000 to 1:3 of final daily dose) with gradual daily escalation.
• Monitored patients closely with blood counts and liver function tests, introducing subsequent drugs only after tolerance of the preceding one.

Main Results:

• Eleven patients (10 male, 8 Chinese) with non-immediate reactions including maculopapular exanthema (MPE), drug-induced hypersensitivity syndrome (DIHS), and Stevens-Johnson syndrome (SJS) were treated.
• Desensitization-rechallenge (D-R) success rates were 77.8% for isoniazid (INH) and 100% for rifampicin (RIF), ethambutol (EMB), pyrazinamide (PZA), and streptomycin.
• Overall, 23 out of 25 (92%) D-R procedures were successful, enabling all patients to complete TB treatment exceeding 5 months without developing drug-resistant TB.

Conclusions:

• Tailored sequential D-R is a viable and successful strategy for managing anti-TB drug allergies when no alternative treatments are available.
• Careful dose escalation, close monitoring, and thorough risk-benefit assessment are essential for successful D-R.
• This approach facilitates the completion of essential TB treatment regimens, preventing the development of drug resistance.