Question

You have been assigned to care for Mr. Underwood, a 32-year-old who has been diagnosed with TB. He goes to the public health department daily to receive his dose of isoniazid and rifampin. Ms. J is your clinical instructor for the day. She has a reputation for asking a lot of questions about the patient’s medications. Ms. J asks you the following questions.

“How do the drugs isoniazid and rifampin work? Why has Mr. Underwood been prescribed two drugs to treat his tuberculosis?” How would you answer this question?

“What is the most common adverse effect of each drug? What would you assess in order to identify the adverse effects?” How would you respond?

Answer 1

Ans) Isoniazid:

Prodrug that must be activated by material enzymes, then inhibits synthesis of mycelia acids (important constituents of the cell wall peculiar to mycobacteria).

• Side effects of Isoniazid:

drowsiness, headache, dizziness, indigestion, nausea, vomiting, menstrual changes, turns body fluid reddish/orange and soft contact lenses may become permanently discolored.

• Adverse effects & Contraindication:

- Allergic skin eruptions, fever, FATAL HEPATOXICITY

- Peripheral/central nervous system defects due to pyridoxine (B6) deficiency. (Diabetics may have more problem with this)

• Nursing intervention while taking Isoniazid:

- Administer 1 hr before or 2 hrs after meals.
- Give pyridoxine to prevent peripheral neuropathy.
- Monitor liver enzyme levels.
- Collect sputum culture early in the morning. Take 3 consecutive specimens
- Encourage eye exams for pts taking isoniazid (can cause visual disturbances.
- Monitor liver function tests.

• Health teaching:

- Teach pt to not take antacids and to avoid alcohol
- Have pt report s/s of neuritis (peripheral neuropathy). Neuritis may not occur if pt eats a balanced diet.
- Avoid direct sunlight.

Rifampin:

- Binds to and inhibits DNA dependent RNA polymerase in prokaryotic cells (most active anti-TB agents known)
- Enters phagocytic cells thus killing intracellular pathogens

- It is commonly used in combination with INH.

- Administer on empty stomach
- Monitor CBC, liver function, renal function studies for evidence of toxicity
-Rifampin reduces effects of contraceptives, quinidine, corticosteroids, warfarin, methadone, digoxin, and hypoglycemic
- Avoid taking aspirin
- Fever, flulike s/s, excessive fatigue, sore throat, or unusual bleeding may indicate an adverse reaction.

• Dosage:

- Oral: 600 mg daily or two or three times weekly.

• Adverse effects:
-Orange red coloration of (saliva and urine, as well as sweat, tears and cerebrospinal fluid)

- Hepatitis

- Flu like syndrome

- Fever
(do not miss/skip doses; flulike syndrome and fever occur when drug is resumed. Contact lenses become discolored and should not be worn).