Jaundice, dark urine, nausea, fatigue, or right upper quadrant pain may signal hepatotoxicity - hold the drug and report.
Before you read
Test yourself first: 4 questions
Question 1 of 4
A client is started on isoniazid (INH) for latent tuberculosis. Which vitamin should the nurse anticipate administering to prevent peripheral neuropathy?
Answer: B. Isoniazid interferes with pyridoxine (vitamin B6) metabolism and can cause peripheral neuropathy. Supplemental vitamin B6 (pyridoxine) is given to prevent this. Vitamins A, C, and B12 do not prevent INH-induced neuropathy.
Question 2 of 4
A client is prescribed isoniazid (INH) as part of treatment for latent tuberculosis. Which vitamin supplement does the nurse anticipate will be prescribed to prevent peripheral neuropathy?
Answer: A. Isoniazid interferes with pyridoxine (vitamin B6) metabolism, increasing the risk of peripheral neuropathy. Vitamin B6 is given to prevent this adverse effect. Vitamin C, vitamin D, and vitamin K do not prevent INH-induced neuropathy.
Question 3 of 4
A client with latent tuberculosis infection asks why treatment is needed even though there are no symptoms. Which response by the nurse is most accurate?
Answer: A. Treating latent TB infection (for example with isoniazid) kills dormant bacteria and prevents progression to active, contagious disease later. The bacteria are present but inactive, so the client is not contagious now but could become so if the infection reactivates. Saying treatment is optional or that the test was wrong is inaccurate.
Question 4 of 4
A client with tuberculosis is prescribed isoniazid and rifampin. Which instruction is most important for the nurse to provide about monitoring for hepatotoxicity?
Answer: A. Both isoniazid and rifampin are hepatotoxic, so the client must report signs of liver injury such as jaundice, dark urine, nausea, anorexia, and right upper quadrant pain, and should avoid alcohol, which increases hepatotoxicity. Taking the drugs with grapefruit juice, doubling missed doses, and ignoring yellowing skin are unsafe instructions.
Keep the streak going with more questions like these, each with a full rationale.
What is isoniazid?
Its major risks are hepatotoxicity and peripheral neuropathy, the latter prevented by vitamin B6. The key principle is monitoring liver function and giving pyridoxine to prevent nerve damage.
Key points to remember
- Isoniazid is bactericidal against Mycobacterium tuberculosis and is a cornerstone of TB therapy.
- Hepatotoxicity is the most serious adverse effect, and risk rises with age and alcohol use.
- Peripheral neuropathy is prevented by giving pyridoxine (vitamin B6).
- It is taken on an empty stomach, 1 hour before or 2 hours after meals, for best absorption.
- It interacts with tyramine- and histamine-containing foods (aged cheese, red wine, certain fish) and can cause a reaction, and it raises phenytoin levels.
- Adherence for the full course is essential to prevent drug-resistant TB.
Nursing priorities
- Administer pyridoxine (vitamin B6) as prescribed to prevent peripheral neuropathy.
- Monitor liver function tests and assess for signs of hepatotoxicity.
- Give on an empty stomach and assess for numbness or tingling.
- Stress strict adherence for the entire course to prevent resistance.
- Assess and counsel the patient to avoid alcohol during therapy.
Labs & values
Patient teaching
- Take vitamin B6 as prescribed to protect your nerves.
- Avoid all alcohol while on this medication.
- Take on an empty stomach and avoid aged cheeses, smoked fish, and certain wines.
- Report yellow skin or eyes, dark urine, fatigue, or numbness and tingling, and keep all follow-up appointments.
Red flags: report now
- Jaundice, dark urine, nausea, fatigue, or right upper quadrant pain may signal hepatotoxicity - hold the drug and report.
- Numbness or tingling in the hands and feet should be reported.
- Avoid alcohol entirely because it greatly increases liver injury risk.
References
Clinical references for this topic
