Second line
The second line drugs (WHO groups 2, 3 and 4) are only used to treat disease that is resistant to first line therapy (i.e., for extensively drug-resistant tuberculosis (XDR-TB) or multidrug-resistant tuberculosis (MDR-TB)). A drug may be classed as second-line instead of first-line for one of three possible reasons: it may be less effective than the first-line drugs (e.g., p-aminosalicylic acid); or, it may have toxic side-effects (e.g., cycloserine); or it may be effective, but unavailable in many developing countries (e.g., fluoroquinolones):
aminoglycosides (WHO group 2): e.g., amikacin (AMK), kanamycin (KM);
polypeptides (WHO group 2): e.g., capreomycin, viomycin, enviomycin;
fluoroquinolones (WHO group 3): e.g., ciprofloxacin (CIP), levofloxacin, moxifloxacin (MXF);
thioamides (WHO group 4): e.g. ethionamide, prothionamide
cycloserine (WHO group 4)
terizidone (WHO group 5)

Third line
Third-line drugs (WHO group 5) include drugs that may be useful, but have doubtful or unproven efficacy:
rifabutin
macrolides: e.g., clarithromycin (CLR);
linezolid (LZD);
thioacetazone (T);
thioridazine;
arginine;
vitamin D;
bedaquiline.These drugs are listed here either because they are not very effective (e.g., clarithromycin) or because their efficacy has not been proven (e.g., linezolid, R207910). Rifabutin is effective, but is not included on the WHO list because for most developing countries, it is impractically expensive. Standard regimen
Rationale and evidence
Tuberculosis has been treated with combination therapy for over fifty years. Drugs are not used singly (except in latent TB or chemoprophylaxis), and regimens that use only single drugs result in the rapid development of resistance and treatment failure. The rationale for using multiple drugs to treat TB are based on simple probability.
Pain in the mouth present daily and persisting for most of the day,
B. Oral mucosa is of normal appearance,
C. Local and systemic diseases have been excluded. Classification
A burning sensation in the mouth may be primary (i.e. burning mouth syndrome) or secondary to systemic or local factors. Other sources refer to a "secondary BMS" with a similar definition, i.e. a burning sensation which is caused by local or systemic factors, or "where oral burning is explained by a clinical abnormality". However this contradicts the accepted definition of BMS which specifies that no cause can be identified. "Secondary BMS" could therefore be considered a misnomer. BMS is an example of dysesthesia, or a distortion of sensation.Some consider BMS to be a variant of atypical facial pain. More recently, BMS has been described as one of the 4 recognizable symptom complexes of chronic facial pain, along with atypical facial pain, temporomandibular joint dysfunction and atypical odontalgia. BMS has been subdivided into three general types, with type two being the most common and type three being the least common. Types one and two have unremitting symptoms, whereas type three may show remitting symptoms. Type 1 - Symptoms not present upon waking, and then increase throughout the day
Type 2 - Symptoms upon waking and through the day
Type 3 - No regular pattern of symptomsSometimes those terms specific to the tongue (e.g. glossodynia) are reserved for when the burning sensation is located only on the tongue.