Standard code for treatment regimens — MSF Tuberculosis — Médecins Sans Frontières 2026

MSFClinical guideline (chapter)Current edition

From Tuberculosis › Chapter 8: Tuberculosis drugs and treatment regimens · Médecins Sans Frontières, Current online edition, 2026

Standardised abbreviations and notation system for tuberculosis drug regimens for clinicians treating drug-susceptible and drug-resistant TB.

In one sentenceMSF standardised coding system uses single-letter abbreviations for TB drugs, with brackets for fixed-dose combinations, slashes for treatment phases, and numbers for duration in months.

Issuer: Médecins Sans Frontières
Edition: Current online edition, 2026
Audience: Clinicians, pharmacists, and public health workers managing tuberculosis
Evidence: Expert consensus and standardised nomenclature
Reviewed: 22 Oct 2026 · GMJ

Read the original on MSF Whole guideline (PDF)

Summary by GMJ Guidelines Desk•Reviewed by Prof. Giorgi Pkhakadze, MD, MPH, PhD•Record updated 22 Oct 2026•Next check Apr 2027

What this guideline says

GMJ summary

This section of the MSF Tuberculosis guideline establishes a standardised coding system for expressing tuberculosis treatment regimens. It provides abbreviations for all first-line drugs used in drug-susceptible TB (isoniazid, rifampicin, pyrazinamide, ethambutol, rifabutin, rifapentine) and second-line drugs for drug-resistant TB, categorised into Groups A, B, and C according to WHO classification, plus ungrouped agents.

The notation system uses specific conventions: drug abbreviations are combined to express regimens, with phases separated by slashes, brackets indicating fixed-dose combinations, hyphens separating second-line drugs, square brackets denoting drugs used but not considered likely effective, and superscript ‘h’ indicating high-dose formulations. Numbers before drug abbreviations indicate treatment duration in months.

Key points

For clinicians — doses and thresholds as stated in the guideline

First-line TB drugs abbreviated as: H (isoniazid), R (rifampicin), Z (pyrazinamide), E (ethambutol), Rfb (rifabutin), P (rifapentine)
Group A second-line drugs: Lfx/Mfx (levofloxacin/moxifloxacin), Bdq (bedaquiline), Lzd (linezolid)
Group B second-line drugs: Cfz (clofazimine), Cs/Trd (cycloserine/terizidone)
Group C includes multiple agents: Dlm (delamanid), Ipm/Cln or Mpm (carbapenems), Am/S (aminoglycosides), Eto/Pto (ethionamide/prothionamide), PAS, and Hh (high-dose isoniazid)
Treatment phases separated by slash (/); brackets ( ) indicate fixed-dose combinations; square brackets [ ] indicate drugs used but not counted as likely effective
Superscript h indicates high-dose formulation; numbers before letters indicate duration in months
Example notation: 2(HRZE)/4(HR) means 2 months intensive phase with 4-drug FDC, followed by 4 months continuation with 2-drug FDC

Categories and abbreviations of TB drugs

Table extracted from the guideline

Categories	TB drugs	Abbreviations
Drug-susceptible TB (first-line)	Isoniazid (standard dose)	H
	Rifampicin	R
	Pyrazinamide	Z
	Ethambutol	E
	Rifabutin	Rfb
	Rifapentine	P
Drug-resistant TB — Group A	Levofloxacin or moxifloxacin	Lfx or Mfx
	Bedaquiline	Bdq
	Linezolid	Lzd
Drug-resistant TB — Group B	Clofazimine	Cfz
	Cycloserine or terizidone	Cs or Trd
Drug-resistant TB — Group C	Delamanid	Dlm
	Ethambutol	E
	Pyrazinamide	Z
	Imipenem/cilastatin or meropenem	Ipm/Cln or Mpm
	Amikacin or streptomycin	Am or S
	Ethionamide or prothionamide	Eto or Pto
	Para-aminosalicylate sodium or para-aminosalicylic acid	PAS
	Isoniazid (high-dose)	Hh
Ungrouped	Pretomanid	Pa

Source: Médecins Sans Frontières, Standard code for treatment regimens — MSF Tuberculosis. Reproduced in summary form.

From the guideline

Verbatim

“For some regimens, the treatment is divided into two phases: intensive phase, and continuation phase.”

— Médecins Sans Frontières, Standard code for treatment regimens — MSF Tuberculosis, Section 8.2.2 (2026)

Editor’s perspective

Why this matters for Georgia and the region

Prof. Giorgi Pkhakadze, MD, MPH, PhD

Editor-in-Chief, Georgian Medical Journal · Chair, Public Health Institute of Georgia · WHO consultant, health and migration

As Editor-in-Chief of the Georgian Medical Journal and a WHO consultant, I recognise that standardised TB regimen notation is fundamental infrastructure for Georgia's National TB Programme, which manages one of the highest MDR-TB burdens in the WHO European Region. This MSF coding system aligns with WHO conventions and facilitates accurate communication between clinicians at the National Centre for Tuberculosis and Lung Diseases, regional facilities, and international technical partners. I would stress to Georgian clinicians the importance of mastering the distinction between grouped and bracketed drugs, as this directly affects how we count likely effective agents when constructing individualised MDR-TB regimens under programmatic conditions. The practical caveat is that while this notation system is elegant on paper, its implementation requires systematic training across all levels of the health system—from prescribers to pharmacists to data managers—and Georgia's decentralised TB services will need sustained capacity-building to ensure consistent application in routine documentation and electronic health records.

ORCID 0000-0001-7609-4515 · Perspective written for the GMJ Guidelines Library, 22 Oct 2026

Applicability

Georgia and the South Caucasus

For Georgia and the South Caucasus region, where multidrug-resistant TB remains a significant public health challenge, standardised regimen notation is essential for clinical communication, treatment monitoring, and reporting. National TB programmes should ensure that all clinicians, pharmacists, and public health workers are trained in this standardised coding system to facilitate accurate prescription, dispensing, documentation, and data exchange with international partners and surveillance systems. The system is particularly relevant given Georgia’s engagement with WHO TB surveillance and the need for precise communication about complex drug-resistant TB regimens.

Questions this guideline answers

Quick answers

What does the notation 2(HRZE)/4(HR) mean?

This indicates a 2-month intensive phase using a fixed-dose combination containing isoniazid, rifampicin, pyrazinamide, and ethambutol, followed by a 4-month continuation phase with a fixed-dose combination containing isoniazid and rifampicin.

How do you distinguish between standard-dose and high-dose isoniazid?

Standard-dose isoniazid is abbreviated as 'H', while high-dose isoniazid is indicated by 'Hh' with a superscript 'h'. High-dose isoniazid is considered a Group C drug for drug-resistant TB regimens.

What do square brackets [ ] around a drug abbreviation indicate?

Square brackets indicate that the drug is being used in the regimen but is not considered as likely effective. For example, [Mfxh] means high-dose moxifloxacin is included but not counted among the likely effective drugs.

How are second-line drugs for drug-resistant TB separated in the notation?

Second-line drugs are separated by hyphens. For example, 18Bdq-Lzd-Cfz-Cs-Dlm indicates 18 months of treatment with bedaquiline, linezolid, clofazimine, cycloserine, and delamanid as individual drugs.

Related on GMJ

Interconnected resources

Dictionary of Public Health

Drugs A–Z

Conditions A–Z

Tuberculosis

GMJ News coverage

Quality & accreditation

Same guideline

Drug Susceptibility Pattern — Tuberculosis — MSF TuberculosisChapter 7: Case definitions
Bacteriological status — MSF TuberculosisChapter 7: Case definitions
High-risk groups — MSF TuberculosisChapter 6: Screening for active tuberculosis
MSF Tuberculosis: Chapter 6.1 Introduction — Screening for active tuberculosis — MSF TuberculosisChapter 6: Screening for active tuberculosis
Guidance for using diagnostic algorithm for pulmonary tuberculosis — MSF TuberculosisChapter 5: Diagnostic algorithm for pulmonary tuberculosis in symptomatic adolescents and adults
Diagnostic approach — MSF TuberculosisChapter 4: Diagnosis of active tuberculosis in children

Standard code for treatment regimens — MSF Tuberculosis

What this guideline says

Key points

Categories and abbreviations of TB drugs

From the guideline