A patient is diagnosed with pulmonary tuberculosis and a treatment with isoniazid, rifampin, pyrazinamide and ethambutol was started. Which of the following statements best explains why ethambutol was added to the therapeutic regimen?

To delay the emergence of drug resistance

To enhance the antibacterial activity of pyrazinamide

To provide antibacterial activity against atypical mycobacteria

To prevent the neurotoxic effects of isoniazide

To prevent Pneumocystis carinii pneumonia

Medicinal Chemistry III- Antitubercular Agents

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| By Suvarna Katti

Suvarna Katti, Medicine Chemistry

Dr. Suvarna Abhijit Katti is an Associate Professor at MGVs Pharmacy College in Panchavati, Nasik. His strengths are in Medicinal Chemistry and Organic Chemistry.

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| Attempts: 292

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1/6 Questions

The mechanism of action of rifampin includes an inhibition of which of the following enzymes?
- DNA dependent RNA-polymerase
- Arabinosyl transferase
- Transpeptidase
- Topoisomerase II
- RNA-dependent DNA-polymerase

About This Quiz

This quiz covers antitubercular agents, focusing on their mechanisms, side effects, and roles in preventing drug resistance in tuberculosis treatment.

Medicinal Chemistry III- Antitubercular Agents - Quiz

2.

A 45-year-old woman complained of blurred vision and inability to distinguish green objects from red objects. The woman, was recently diagnosed with tuberculosis, has been receiving a 4 drug combination regimen for two months. Which of the following drugs has most likely caused these adverse effects?
- Isoniazid
- Pyrazinamide
- Rifampin
- Ethambutol
- Streptomycin
Correct Answer

A. Ethambutol

Explanation

Ethambutol is the most likely cause of the woman's blurred vision and inability to distinguish green objects from red objects. Ethambutol is known to cause optic neuritis, which can result in visual disturbances such as blurred vision and color blindness. The other drugs listed do not typically cause these specific adverse effects.

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3.
- Which of the following antimycobacterial drugs is inactivated by hepatic acetylation, the rate of which depends on genetic background?
- Streptomycin
- Ethambutol
- Rifampin
- Isoniazid
- Pyrazinamide
- Option 6
Correct Answer

A. Isoniazid

Explanation

Isoniazid is the correct answer because it is known to be inactivated by hepatic acetylation, and the rate of this inactivation depends on an individual's genetic background. This means that different individuals may metabolize isoniazid at different rates, leading to varying levels of drug activity in the body. This genetic variability can impact the effectiveness and side effects of isoniazid treatment for tuberculosis.

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4.

The patient was diagnosed with tuberculosis and started on a regimen of 4 antitubercular drugs one month ago. Lab results showed raised serum uric acid of 13 mg /dl. Which of the following drugs has most likely caused the patient’s current symptoms?
- Rifampin
- Pyrazinamide
- Isoniazid
- Streptomycin
Correct Answer

A. Pyrazinamide

Explanation

Pyrazinamide is the most likely drug that has caused the patient's raised serum uric acid levels. Pyrazinamide is known to cause hyperuricemia, which is an increase in uric acid levels in the blood. This side effect is more common in patients with pre-existing hyperuricemia or gout. Rifampin, isoniazid, and streptomycin are not typically associated with elevated uric acid levels.

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5.

A patient reports tingling sensation in limbs and arms sometimes feel heavy. He was diagnosed with pulmonary tuberculosis and has been receiving isoniazid, rifampin, pyrazinamide and ethambutol for two months. Which of the following drugs would be most appropriate to treat his current symptoms?
- Folic acid
- Pyridoxine
- Cyanocobalamin
- Vitamic C
Correct Answer

A. Pyridoxine

Explanation

The patient is experiencing symptoms of peripheral neuropathy, which can be a side effect of the anti-tuberculosis medications. Pyridoxine, also known as vitamin B6, is commonly used to prevent and treat peripheral neuropathy caused by isoniazid. It helps to protect and repair the nerves, reducing the tingling sensation and heaviness in the limbs. Folic acid, cyanocobalamin, and vitamin C do not have direct effects on peripheral neuropathy.

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6.

A patient is diagnosed with pulmonary tuberculosis and a treatment with isoniazid, rifampin, pyrazinamide and ethambutol was started. Which of the following statements best explains why ethambutol was added to the therapeutic regimen?
- To enhance the antibacterial activity of pyrazinamide
- To provide antibacterial activity against atypical mycobacteria
- To prevent the neurotoxic effects of isoniazide
- To prevent Pneumocystis carinii pneumonia
- To delay the emergence of drug resistance
Correct Answer

A. To delay the emergence of drug resistance

Explanation

Ethambutol was added to the therapeutic regimen to delay the emergence of drug resistance. This is because ethambutol has a different mechanism of action compared to the other drugs in the regimen (isoniazid, rifampin, and pyrazinamide). By using multiple drugs with different mechanisms of action, the chances of the bacteria developing resistance to all of them simultaneously are reduced. This helps to ensure the effectiveness of the treatment and prevent the development of drug-resistant strains of tuberculosis.

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Sep 19, 2020

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Suvarna Katti

Medicinal Chemistry III- Antitubercular Agents

The mechanism of action of rifampin includes an inhibition of which of the following enzymes?

Quiz Preview

Which of the following antimycobacterial drugs is inactivated by hepatic acetylation, the rate of which depends on genetic background?

The patient was diagnosed with tuberculosis and started on a regimen of 4 antitubercular drugs one month ago. Lab results showed raised serum uric acid of 13 mg /dl. Which of the following drugs has most likely caused the patient’s current symptoms?

A patient reports tingling sensation in limbs and arms sometimes feel heavy. He was diagnosed with pulmonary tuberculosis and has been receiving isoniazid, rifampin, pyrazinamide and ethambutol for two months. Which of the following drugs would be most appropriate to treat his current symptoms?

A patient is diagnosed with pulmonary tuberculosis and a treatment with isoniazid, rifampin, pyrazinamide and ethambutol was started. Which of the following statements best explains why ethambutol was added to the therapeutic regimen?