Drug-Resistant Tuberculosis

Introduction

If you or someone you care for has been told the tuberculosis (TB) infection is “drug-resistant,” the news can feel heavy. Standard TB is hard enough; resistant TB sounds harder. The honest picture is that drug-resistant tuberculosis (DR-TB) is more complex to treat than ordinary TB, but it is treatable, and the way it is treated has changed substantially over the last few years.

Newer all-oral regimens, shorter treatment durations for many patients, better diagnostic tools, and structured monitoring have improved outcomes worldwide. The World Health Organization (WHO) and India’s National TB Elimination Programme (NTEP) have both updated their guidance to reflect these changes.

This article is written for patients and family members who already know that resistant TB is part of the picture — either confirmed by testing or under investigation. It explains what drug resistance means, the types of DR-TB, how it is diagnosed, the modern treatment regimens, what to expect during the months of treatment, side effects and how they are managed, and life after cure.

What Is Drug-Resistant Tuberculosis?

Tuberculosis is caused by a slow-growing bacterium called Mycobacterium tuberculosis. It usually affects the lungs (pulmonary TB) but can affect lymph nodes, bones, the brain’s lining, the abdomen, and other organs (extrapulmonary TB).

Standard, drug-sensitive TB responds to a combination of four medicines — isoniazid, rifampicin, pyrazinamide, and ethambutol — taken for around six months. These are called first-line drugs.

Drug-resistant tuberculosis means the TB bacteria no longer respond to one or more of these standard medicines. The bacteria continue to grow even when the drug is in the body, so the infection is not controlled. Resistant TB requires different drugs — called second-line or newer drugs — and usually a longer course of treatment.

Resistance can develop in two ways:

• Acquired resistance — a person started TB treatment but the bacteria developed resistance during the course, usually because of irregular dosing, dose interruptions, incorrect prescriptions, or poor-quality medicines.
• Primary (transmitted) resistance — a person was infected from the start with a strain that was already resistant, passed on from someone else with resistant TB. This is increasingly common in settings where DR-TB is widespread.

Doctors classify DR-TB based on which drugs the bacteria no longer respond to. The classification matters because it shapes the treatment plan.

Rifampicin-resistant TB (RR-TB)

Rifampicin is one of the two most powerful first-line TB drugs. When the bacteria are resistant to rifampicin (with or without resistance to other drugs), the case is treated as rifampicin-resistant TB. In practice, RR-TB is managed using the same regimens as MDR-TB.

Multidrug-resistant TB (MDR-TB)

MDR-TB is defined as resistance to at least the two strongest first-line drugs: isoniazid and rifampicin. MDR-TB is the most common form of DR-TB worldwide.

Pre-extensively drug-resistant TB (pre-XDR-TB)

WHO updated this definition in 2021. Pre-XDR-TB is MDR-TB or RR-TB that is also resistant to any fluoroquinolone (such as levofloxacin or moxifloxacin). Fluoroquinolones are a key second-line drug class, so losing them narrows the treatment options.

Extensively drug-resistant TB (XDR-TB)

XDR-TB is pre-XDR-TB that is also resistant to at least one of the newer, most effective drugs — bedaquiline or linezolid. XDR-TB is the most difficult form of resistant TB to treat, but newer agents have made cure possible in many cases that would once have been considered untreatable.

Mono- and poly-resistant TB

Some forms of TB are resistant to one first-line drug (mono-resistance) or to more than one but not the combination that defines MDR-TB (poly-resistance). These cases are managed with modified regimens and are less complex than MDR or XDR-TB.

Causes and Risk Factors

Drug resistance is something that happens to the bacteria, not something the person did wrong — though certain situations increase the risk that resistance develops or spreads.

Factors associated with the development or transmission of drug-resistant TB include:

• A previous course of TB treatment, especially one that was interrupted, incomplete, or used the wrong combination of drugs
• Close, prolonged contact with someone who has untreated or poorly controlled DR-TB
• Living, working, or seeking care in settings where DR-TB is common
• HIV infection, which weakens the immune system and is associated with higher TB rates overall
• Diabetes, which roughly triples the risk of TB and may complicate treatment
• Malnutrition, which weakens host defences and slows recovery
• Use of poor-quality or counterfeit TB medicines
• Smoking and heavy alcohol use, which worsen outcomes

None of these by themselves causes resistance to appear — resistance emerges through genetic changes in the bacteria — but they increase the likelihood of being exposed to a resistant strain or of resistance emerging during treatment.

Signs and Symptoms

The symptoms of DR-TB are not different from those of standard TB. What is often different is the pattern: symptoms persist or return despite a previous course of TB medicines, or worsen during treatment instead of improving.

Common symptoms include:

• Cough lasting more than two to three weeks, often with sputum
• Coughing up blood or blood-streaked sputum (haemoptysis)
• Chest pain or discomfort with breathing
• Low-grade fever, especially in the evening
• Drenching night sweats
• Unintended weight loss
• Loss of appetite
• Severe tiredness and weakness

When TB has spread to other organs, additional symptoms can appear — swollen lymph nodes, back pain (spinal TB), persistent headache or vomiting (TB meningitis), or abdominal pain.

If you have started TB treatment but your symptoms are not improving after about two months, or if symptoms come back after finishing a previous course, the possibility of drug resistance is one of the reasons doctors will re-investigate.

Diagnosis — Confirming Drug Resistance

Rapid molecular tests

These tests detect TB bacteria and key resistance genes directly from sputum within hours.

• Xpert MTB/RIF and Xpert MTB/RIF Ultra — detect TB and rifampicin resistance. WHO recommends this as the initial test for anyone with presumed TB.
• Xpert MTB/XDR — a newer test that, in addition, detects resistance to isoniazid, fluoroquinolones, and other second-line drugs.
• Line probe assays (LPAs) — detect resistance to first-line drugs (rifampicin and isoniazid) and second-line drugs (fluoroquinolones, injectables).

Culture and phenotypic drug susceptibility testing (DST)

The bacteria are grown in the laboratory and exposed to each drug to see whether they survive. This is the most complete way to map resistance but takes several weeks because TB is slow growing.

Imaging

Chest X-ray and, where needed, CT scan show the extent of lung involvement — including cavities, infiltrates, or scarring. Imaging does not diagnose drug resistance directly but helps assess severity and monitor response.

Additional tests

• HIV testing is offered to everyone with TB because HIV co-infection changes treatment planning.
• Blood tests assess liver and kidney function, blood counts, blood sugar (for diabetes), and electrolytes — all important before starting drugs that can affect these systems.
• ECG may be done at the start because some DR-TB drugs can affect the heart’s electrical conduction (QT interval).
• Vision and hearing tests may be done because certain drugs can affect the eyes (ethambutol, linezolid) or hearing (older injectables, if used).

Treatment of Drug-Resistant TB

Treatment of DR-TB has changed significantly. Older regimens lasted 18 to 24 months, included painful daily injections, and had heavy side effects. Current WHO guidance and India’s NTEP both prioritise shorter, all-oral regimens built around newer drugs — chiefly bedaquiline, pretomanid, and linezolid — alongside other agents.

The exact regimen depends on the resistance pattern, where the TB is in the body, previous treatment history, age, pregnancy status, other medical conditions, and how the body tolerates each drug.

Shorter all-oral regimens

For many people with MDR-TB or RR-TB, WHO now recommends a six-month BPaLM regimen: bedaquiline, pretomanid, linezolid, and moxifloxacin. For pre-XDR-TB (where moxifloxacin is not effective), BPaL — the same regimen without moxifloxacin — is used. These regimens have transformed DR-TB care because they are shorter, taken entirely as tablets, and have shown high cure rates in clinical trials and programmatic settings.

An older nine-month all-oral regimen is also still used in some settings, particularly for patients with extensive disease, intolerance to one of the BPaL drugs, or specific contraindications.

Longer individualised regimens

For some patients — for example, those with XDR-TB, extensive lung damage, complicated extrapulmonary disease, or intolerance to the standard short regimen — treatment is built case by case. Such regimens last 18 to 20 months and combine several drugs chosen from a priority list that includes bedaquiline, linezolid, levofloxacin or moxifloxacin, clofazimine, cycloserine or terizidone, ethionamide, delamanid, and others.

Drugs commonly used in DR-TB

• Bedaquiline — a cornerstone of modern DR-TB regimens; blocks energy production in TB bacteria.
• Pretomanid — part of BPaL/BPaLM; active against actively replicating and dormant bacteria.
• Linezolid — highly active but requires careful monitoring for side effects.
• Fluoroquinolones (levofloxacin, moxifloxacin) — key second-line drugs; not used if the strain is resistant to them.
• Clofazimine — an older drug that has found a renewed role in DR-TB.
• Cycloserine or terizidone — used in longer regimens.
• Delamanid — a newer drug used in selected cases, including in children.

Older injectable drugs such as kanamycin, amikacin, and capreomycin are no longer recommended by WHO as part of routine DR-TB treatment because their side-effect profile, particularly permanent hearing loss, was severe and newer oral drugs have proven more effective.

Hospitalisation

Most patients with DR-TB are now treated as outpatients. Hospital admission is used selectively — for severe disease, very low body weight, complications, side effects that need closer monitoring, or when home conditions make safe outpatient treatment difficult during the infectious phase.

Surgery for selected cases

In a small number of patients with localised lung damage that does not respond to medicines, thoracic surgery to remove the affected portion of lung may be considered alongside continued drug treatment. This is an uncommon path and is decided by a multidisciplinary team.

Adherence and Directly Observed Treatment

The single most important factor in curing DR-TB is taking every dose, on time, for the full duration of the regimen. Missing doses gives surviving bacteria the chance to multiply and develop further resistance — potentially turning treatable DR-TB into harder-to-treat XDR-TB.

To support adherence, TB programmes use several approaches:

• Directly observed treatment (DOT) — a treatment supporter (a community health worker, family member, or other trained person) watches the patient take each dose.
• Video-observed therapy (VOT) — the patient takes the dose on a video call or sends a short video for review. WHO recognises VOT as an acceptable alternative to in-person DOT.
• Daily-dose reminders — phone reminders, electronic pillboxes, or app-based tools.
• Patient counselling and support — education at the start of treatment, regular check-ins, and addressing the practical and emotional barriers to staying on therapy.

DR-TB drugs are powerful, and side effects are common. The good news is that most side effects can be managed without stopping the regimen, especially when caught early. Regular check-ups during treatment are designed to spot side effects before they become serious.

Common side effects

• Nausea, vomiting, and stomach upset — usually settle with dose timing, food adjustments, or anti-sickness medication.
• Skin pigmentation — clofazimine commonly causes a reversible brownish-red skin tone.
• Joint pain or muscle aches — usually manageable with simple painkillers.
• Tiredness and low mood — common throughout treatment.

Serious side effects that need close monitoring

• Peripheral neuropathy — tingling, numbness, or pain in the hands and feet, most often linked to linezolid. Often improves with dose adjustment.
• Optic neuritis — reduced or blurred vision, also linked to linezolid (and ethambutol). Requires prompt reporting.
• Bone marrow suppression — low red cells, white cells, or platelets, linked to linezolid. Detected on routine blood tests.
• Liver toxicity (hepatitis) — nausea, loss of appetite, yellowing of eyes or skin, dark urine. Liver function is monitored regularly.
• QT prolongation — an effect on the heart’s electrical rhythm that can be caused by bedaquiline, moxifloxacin, clofazimine, and delamanid. Monitored with ECGs.
• Psychiatric effects — cycloserine and terizidone can cause mood changes, anxiety, depression, or rarely psychosis.
• Hypothyroidism — some drugs can lower thyroid function; checked with blood tests.
• Hearing loss — mainly a concern with older injectable agents, which is one reason WHO has moved away from them.

Regular monitoring is built into DR-TB care. It tracks both how well the treatment is working and whether side effects are developing.

Typical monitoring includes:

• Monthly sputum tests — smear and culture to confirm the bacteria are clearing.
• Periodic chest X-rays — to follow lung healing.
• Weight and clinical review — weight gain is one of the most reliable signs of recovery.
• Blood tests — for liver function, kidney function, blood counts, electrolytes, and thyroid function.
• ECGs — for QT interval, especially in the first months and when doses change.
• Vision and hearing checks — on a schedule, depending on the drugs used.

“Culture conversion” — when sputum cultures stop growing TB bacteria — is a key milestone, usually expected within the first two to three months. It indicates that the treatment is working and the person is becoming non-infectious.

Infection Control at Home

People with pulmonary DR-TB can spread the bacteria to others through coughing, sneezing, and prolonged close indoor contact — mostly during the early weeks of treatment, before culture conversion. Simple infection-control measures reduce that risk substantially.

• Cover the nose and mouth when coughing or sneezing.
• Wear a surgical mask in shared spaces during the infectious phase.
• Sleep in a separate, well-ventilated room if possible.
• Keep windows open to allow fresh air through the home.
• Spend time outdoors in sunlight where practical — sunlight inactivates TB bacteria.
• Limit visits from young children, people with HIV, and people on immunosuppressive treatment during the infectious phase.
• Ensure household contacts are evaluated for TB infection and disease.

Once sputum cultures have converted to negative and the treating team has confirmed the person is no longer infectious, these restrictions ease.

Nutrition and Lifestyle

Nutrition supports the immune system and helps the body tolerate months of treatment. Many people with active TB are underweight at diagnosis, and weight recovery is part of the cure.

Practical nutritional points that DR-TB programmes commonly emphasise:

• Eat enough total calories to regain lost weight.
• Include adequate protein from sources such as eggs, dairy, legumes, fish, meat, and pulses.
• Include fruits and vegetables for vitamins and minerals.
• Some regimens include vitamin B6 (pyridoxine) supplementation to prevent neuropathy from certain drugs — this is prescribed, not over-the-counter.
• Stay well hydrated.
• Stop smoking completely — smoking damages already-injured lungs and worsens outcomes.
• Avoid alcohol, particularly during the months on liver-affecting drugs.

Light physical activity, as tolerated, helps maintain strength. As treatment progresses and energy returns, gradually rebuilding activity is part of recovery.

Treatment in Special Situations

HIV co-infection

People with both HIV and DR-TB are treated for both. Antiretroviral therapy (ART) is started or continued, with attention to drug interactions between TB drugs and ART. Outcomes have improved markedly when both infections are treated together.

Pregnancy and breastfeeding

DR-TB during pregnancy is managed carefully. Some drugs are preferred and others avoided during pregnancy. The treatment plan is built by a team that includes a pulmonologist or TB specialist and an obstetrician. Untreated DR-TB is more dangerous to mother and baby than the modern regimens used in pregnancy.

Diabetes

Diabetes is common alongside TB and makes treatment more challenging. Blood sugar is monitored closely, and diabetes care is adjusted in parallel with TB treatment.

Liver or kidney disease

Pre-existing liver or kidney conditions affect drug choice and dosing. Drugs are selected to minimise organ stress, and monitoring is intensified.

Drug-Resistant TB in Children

Children can develop DR-TB, usually after being infected by an adult household contact with DR-TB. Diagnosis in children is harder because they often cannot produce a good sputum sample and the bacterial load is lower. Diagnosis frequently relies on a combination of contact history, symptoms, chest imaging, tuberculin or interferon-gamma release tests, and molecular testing of any available samples (gastric aspirate, induced sputum, lymph node aspirate).

Treatment of paediatric DR-TB follows the same general principles as in adults but with several important differences:

• Doses are weight-based and adjusted as the child grows.
• Child-friendly dispersible tablet formulations of key drugs (including bedaquiline and delamanid) are now available and recommended by WHO.
• Older injectable drugs are avoided, particularly in young children, because of permanent hearing loss risk.
• Shorter all-oral regimens are increasingly used in children, with regimen choice guided by age, weight, and resistance pattern.
• Side-effect monitoring includes growth, development, vision, and hearing.
• Family-centred care — including treating the source case promptly — protects both the child and other household members.

Children generally tolerate DR-TB treatment well and have good cure rates when treatment is started early and supported throughout.

Complications

Even with successful treatment, DR-TB can leave consequences, especially when the lungs were extensively affected before treatment began.

Possible complications include:

• Lung scarring and reduced lung function — sometimes persistent breathlessness on exertion after cure.
• Bronchiectasis — permanently widened airways that can be prone to recurrent infections.
• Recurrent haemoptysis — coughing up blood, sometimes from old cavities or scarred areas.
• Pulmonary hypertension — raised pressure in the lung blood vessels, in severe cases.
• Aspergilloma — a fungal ball that can form inside an old TB cavity.
• Permanent damage from drug side effects — for example, peripheral neuropathy that has not fully resolved.

Most of these complications are more likely when treatment was started late or when there were long delays in diagnosing resistance. They become less common as faster diagnostics and shorter, better-tolerated regimens become standard.

When to Seek Urgent Care

During DR-TB treatment, certain symptoms need same-day or emergency review rather than waiting for the next scheduled appointment:

• Severe breathlessness or sudden worsening of breathing
• Coughing up large amounts of blood
• Chest pain that is severe or new
• Yellowing of the eyes or skin, dark urine, or persistent vomiting (possible liver injury)
• New visual changes — blurring, reduced vision, or colour vision changes
• New numbness, weakness, or severe tingling in the hands or feet
• Fainting, palpitations, or irregular heartbeat
• Severe mood changes, confusion, or thoughts of self-harm
• High fever with shivering during a previously stable course

Reporting symptoms early lets the team adjust the regimen before serious harm develops — and most adjustments can be made without compromising the chance of cure.

Long-Term Outlook

DR-TB outcomes have improved substantially in recent years. With the newer all-oral regimens, programmatic cure rates have moved closer to those achieved in drug-sensitive TB — particularly when treatment is started early, taken consistently, and supported by good monitoring. Even XDR-TB, once considered nearly untreatable, now has meaningful cure rates with bedaquiline- and linezolid-based regimens.

Most people who complete DR-TB treatment go on to live normal lives. Some are left with reduced lung function or other long-term effects, and a smaller number need ongoing pulmonology follow-up — including pulmonary rehabilitation, treatment of bronchiectasis, or management of post-TB lung disease.

Follow-up after the end of treatment usually continues for a year or two, with periodic clinical review, sputum tests, and imaging to confirm cure is sustained and to pick up any signs of relapse promptly.

Preventing Drug-Resistant TB and Protecting Others

Prevention of DR-TB happens at several levels:

• Completing TB treatment fully when first prescribed — this prevents resistance from developing during treatment.
• Using correct regimens — treating TB with the right drugs at the right doses, prescribed by clinicians familiar with current guidelines.
• Contact investigation — family members and close contacts of someone with DR-TB are screened for TB infection and disease.
• TB preventive treatment — in selected contacts, preventive medication may be offered, with regimen choice guided by the resistance pattern of the source case.
• Infection control — ventilation, masking during the infectious phase, and reducing prolonged indoor exposure.
• Managing risk conditions — HIV, diabetes, and malnutrition each increase TB risk and benefit from good control.

Frequently Asked Questions

Is drug-resistant TB curable?

Yes. MDR-TB, pre-XDR-TB, and even XDR-TB are curable in the majority of cases with modern regimens, early diagnosis, and consistent adherence. Cure rates have improved markedly with all-oral, shorter regimens based on bedaquiline, pretomanid, linezolid, and related drugs.

How long is treatment now?

For many people with MDR-TB or pre-XDR-TB, current WHO-recommended regimens last six to nine months. Older or individualised regimens for more complex cases can last 18 to 20 months. The treating team decides the regimen based on the resistance pattern, the extent of disease, and individual factors.

Will I need to be hospitalised?

Most DR-TB treatment is given on an outpatient basis. Hospital admission is used selectively — for severe disease, complications, side effects that need close observation, or specific social circumstances.

How long am I contagious?

People with pulmonary DR-TB are infectious before and during the early weeks of treatment. Most become non-infectious after effective treatment is established and sputum cultures convert to negative, typically within the first two to three months. The treating team confirms when normal household contact and work or school can resume.

Can I work or go to school during treatment?

During the infectious phase, time off and isolation are usually advised. After culture conversion and with the team’s clearance, many people return to work or school while continuing medication. Energy levels and side effects vary, so gradual return is common.

Why are injections no longer used?

The older injectable drugs (kanamycin, amikacin, capreomycin) caused permanent hearing loss in many patients and were difficult to take. Newer oral drugs — bedaquiline, linezolid, pretomanid, delamanid — have been shown to be at least as effective and safer, so WHO no longer recommends the older injectables in routine DR-TB treatment.

Will I develop another resistant strain?

The main way new resistance develops is through inconsistent treatment — missed doses, wrong combinations, or stopping early. Taking the full regimen as prescribed dramatically reduces this risk.

What if I cannot tolerate a drug?

Tell the treating team. Many side effects can be managed without changing the regimen. When a change is needed, the team substitutes an appropriate alternative. Do not stop or change drugs on your own — this is one of the main causes of treatment failure and further resistance.

Are family members at risk?

Household contacts — especially those sharing sleeping space — have some risk of infection. Contact screening is part of standard DR-TB care. Children, people with HIV, and others at higher risk are evaluated and offered preventive treatment when appropriate.

Can I have children after DR-TB?

Yes. DR-TB treatment does not generally affect fertility, and most people resume normal reproductive lives after cure. Pregnancy during treatment is managed with adjusted regimens. Discuss timing with your treating team.

Does TB come back after cure?

Relapse is possible but uncommon when treatment has been completed correctly. Follow-up visits after the end of treatment are designed to pick up relapse early. Any return of cough, weight loss, or fever in the months or years after cure should be reported promptly.

Conclusion

A diagnosis of drug-resistant tuberculosis is serious, but it is no longer the picture it once was. Modern shorter, all-oral regimens, faster diagnostics, better side-effect management, and structured follow-up have made cure possible for the great majority of patients — including those with the most resistant forms of the disease.

The path is still demanding. Treatment lasts months, requires daily medicines, involves regular monitoring, and asks patients and families to stay engaged across a long course of care. But the work is finite, the regimens are better than ever before, and the goal — cure and return to normal life — is achievable for most people who start treatment today.