Antituberculosis medications

00:00 / 00:00

Videos

Notes

Antituberculosis medications

Prerequisite basic sciences

Prerequisite basic sciences

Attributable risk (AR)

Bias in interpreting results of clinical studies

Bias in performing clinical studies

Clinical trials

Confounding

DALY and QALY

Direct standardization

Disease causality

Incidence and prevalence

Indirect standardization

Interaction

Mortality rates and case-fatality

Odds ratio

Positive and negative predictive value

Prevention

Relative and absolute risk

Selection bias

Sensitivity and specificity

Study designs

Test precision and accuracy

Acyanotic congenital heart defects: Pathology review

Adrenal masses: Pathology review

Bacterial and viral skin infections: Pathology review

Bone tumors: Pathology review

Coagulation disorders: Pathology review

Congenital neurological disorders: Pathology review

Cyanotic congenital heart defects: Pathology review

Extrinsic hemolytic normocytic anemia: Pathology review

Eye conditions: Inflammation, infections and trauma: Pathology review

Eye conditions: Refractive errors, lens disorders and glaucoma: Pathology review

Headaches: Pathology review

Intrinsic hemolytic normocytic anemia: Pathology review

Leukemias: Pathology review

Lymphomas: Pathology review

Macrocytic anemia: Pathology review

Microcytic anemia: Pathology review

Mixed platelet and coagulation disorders: Pathology review

Nasal, oral and pharyngeal diseases: Pathology review

Nephritic syndromes: Pathology review

Nephrotic syndromes: Pathology review

Non-hemolytic normocytic anemia: Pathology review

Pediatric brain tumors: Pathology review

Pediatric musculoskeletal disorders: Pathology review

Platelet disorders: Pathology review

Renal and urinary tract masses: Pathology review

Seizures: Pathology review

Viral exanthems of childhood: Pathology review

Pharmacodynamics: Agonist, partial agonist and antagonist

Pharmacodynamics: Desensitization and tolerance

Pharmacodynamics: Drug-receptor interactions

Pharmacokinetics: Drug absorption and distribution

Pharmacokinetics: Drug elimination and clearance

Pharmacokinetics: Drug metabolism

Prerequisite basic sciences

Growth hormone and somatostatin

Prerequisite basic sciences

Breastfeeding

Prerequisite basic sciences

Androgens and antiandrogens

Estrogens and antiestrogens

Miscellaneous cell wall synthesis inhibitors

Protein synthesis inhibitors: Tetracyclines

Cell wall synthesis inhibitors: Penicillins

Antihistamines for allergies

Acetaminophen (Paracetamol)

Non-steroidal anti-inflammatory drugs

Antimetabolites: Sulfonamides and trimethoprim

Antituberculosis medications

Cell wall synthesis inhibitors: Cephalosporins

Cell wall synthesis inhibitors: Penicillins

DNA synthesis inhibitors: Fluoroquinolones

DNA synthesis inhibitors: Metronidazole

Miscellaneous cell wall synthesis inhibitors

Miscellaneous protein synthesis inhibitors

Protein synthesis inhibitors: Aminoglycosides

Protein synthesis inhibitors: Tetracyclines

Bronchodilators: Beta 2-agonists and muscarinic antagonists

Bronchodilators: Leukotriene antagonists and methylxanthines

Pulmonary corticosteroids and mast cell inhibitors

Glucocorticoids

Bronchodilators: Beta 2-agonists and muscarinic antagonists

Bronchodilators: Leukotriene antagonists and methylxanthines

Azoles

Glucocorticoids

Pulmonary corticosteroids and mast cell inhibitors

Acetaminophen (Paracetamol)

Non-steroidal anti-inflammatory drugs

Antimetabolites: Sulfonamides and trimethoprim

Cell wall synthesis inhibitors: Cephalosporins

Cell wall synthesis inhibitors: Penicillins

Miscellaneous protein synthesis inhibitors

Protein synthesis inhibitors: Tetracyclines

Pharmacodynamics: Agonist, partial agonist and antagonist

Pharmacodynamics: Desensitization and tolerance

Pharmacodynamics: Drug-receptor interactions

Pharmacokinetics: Drug absorption and distribution

Pharmacokinetics: Drug elimination and clearance

Pharmacokinetics: Drug metabolism

Cell wall synthesis inhibitors: Cephalosporins

Glucocorticoids

Miscellaneous protein synthesis inhibitors

Anticonvulsants and anxiolytics: Barbiturates

Anticonvulsants and anxiolytics: Benzodiazepines

Nonbenzodiazepine anticonvulsants

Cell wall synthesis inhibitors: Cephalosporins

Cell wall synthesis inhibitors: Penicillins

Miscellaneous cell wall synthesis inhibitors

Assessments

Antituberculosis medications

Flashcards

0 / 36 complete

USMLE® Step 1 questions

0 / 6 complete

USMLE® Step 2 questions

0 / 8 complete

Flashcards

Antituberculosis medications

of complete

Questions

USMLE® Step 1 style questions USMLE

of complete

USMLE® Step 2 style questions USMLE

of complete

A 42-year-old man presents to his primary care provider due to worsening visual disturbances for the past two weeks. He has experienced blurry vision and difficulty differentiating between red and green lights at traffic intersections. Medical history is notable for active tuberculosis diagnosed seven weeks ago. He is currently taking multiple antituberculosis medications. Temperature is 37.0°C (98.6°F), blood pressure is 123/78 mmHg, and pulse is 72/min. Physical examination reveals reduced central visual acuity in both eyes. An Ishihara color perception test is performed, and the patient is noted to have red-green color blindness. Which of the following best describes the mechanism of action of the medication most likely responsible for this patient’s symptoms?  

External References

First Aid

2022

2021

2020

2019

2018

2017

2016

Ethambutol p. 193, 194

Transcript

Antituberculosis medications are agents used to treat tuberculosis, a disease caused by the bacteria Mycobacterium tuberculosis.

Mycobacteria are an interesting bunch, they’re slender, rod-shaped, and need oxygen to survive, in other words, they’re “strict aerobes.”

They’ve got an unusually waxy cell wall, which is mainly a result of the production of mycolic acid.

This waxy cell wall makes them incredibly hardy, and allows them to resist weak disinfectants and survive on dry surfaces for months at a time.

Antituberculosis medications act mainly by preventing the production of mycolic acid and the synthesis of this cell wall.

Although about two billion people worldwide are infected with tuberculosis, or simply ‘TB, the vast majority, about 90-95%, don’t develop symptoms. And this is because usually the immune system can contain it.

So Mycobacterium tuberculosis is usually transmitted via inhalation, which is how they gain entry into the lungs.

TB can avoid the mucus traps and make its way to the deep airways and alveoli where we have macrophages which eat up foreign cells, digest, and destroy them.

With TB, they recognize foreign proteins on their cell surface, and phagocytize them, or essentially package them into a space called a phagosome.

With most cases, the macrophage then fuses the phagosome with a lysosome, which has hydrolytic enzymes that can pretty much break down any biochemical molecule.

TB’s tricky though, and once inside the macrophage, they produce a protein that inhibits this fusion, which allows the mycobacterium to survive.

It doesn’t just survive, though, it proliferates, and creates a localized infection.

Three weeks after initial infection, cell-mediated immunity kicks in, and immune cells surround the site of TB infection, creating a granuloma.

The tissue inside the middle dies as a result, a process referred to as caseous necrosis. This area is known as a “Ghon focus”.

In some cases, the mycobacteria is killed off by the immune system, and that’s the end of that.

Summary

Anti-tuberculosis (TB) medications are drugs used to treat tuberculosis. Common TB medications include Isoniazid (INH), Rifampin (RIF) Pyrazinamide (PZA), and Ethambutol (EMB). Other TB drugs include Streptomycin, Capreomycin, Amikacin, and Levofloxacin. TB drugs are typically administered in combination, which helps minimize resistance to one of the drugs.

Side effects of TB drugs include vitamin B6 deficiency for isoniazid. This is prevented by taking isoniazid with vitamin B6 supplements (pyridoxine). Other side effects include hepatotoxicity for isoniazid, ethambutol, and pyrazinamide; and thrombocytopenia and neutropenia for Rifampin.

Sources

  1. "Katzung & Trevor's Pharmacology Examination and Board Review,12th Edition" McGraw-Hill Education / Medical (2018)
  2. "Rang and Dale's Pharmacology" Elsevier (2019)
  3. "Goodman and Gilman's The Pharmacological Basis of Therapeutics, 13th Edition" McGraw-Hill Education / Medical (2017)
  4. "Treatment of Latent Tuberculosis Infection" Annals of Internal Medicine (2017)
  5. "Multidrug-Resistant Tuberculosis and Extensively Drug-Resistant Tuberculosis" Cold Spring Harbor Perspectives in Medicine (2015)
  6. "Molecular mechanism of the synergistic activity of ethambutol and isoniazid against Mycobacterium tuberculosis" Journal of Biological Chemistry (2018)
  7. "WHO consolidated guidelines on tuberculosis. Module 4" World Health Organization (2020)
Elsevier

Copyright © 2023 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.

RELX