Isoniazid (inh)

1. ISONIAZID (INH)
PREPARED BY,
MRS. RIJO LIJO

2. MECHANISM OF ACTION
 Mechanism :
 Isoniazid inhibits the synthesis of mycologic acids, an essential
component of the bacterial cell wall. At therapeutic levels isoniazid
is bactericidal against actively growing intracellular and
extracellular Mycobacterium tuberculosis organisms. lsoniazid
resistant Mycobacterium tuberculosis bacilli develop rapidly when
lsoniazid monotherapy is administered.

3. INDICATION :
 Prophylaxis and treatment of tuberculosis.

4. CONTRAINDICATIONS :
 Isoniazid is contraindicated in patients who develop severe
hypersensitivity reactions, including drug -induced hepatitis;
previous isoniazid-associated hepatic injury; severe adverse
reactions to isoniazid such as drug fever, chills, arthritis; and acute
liver disease of any etiology.

5. DOSING :
 10 mg/kg/day PO for the entire course of treatment. Max: 300
mg/day.

6. ADVERSE EFFECT :
 Common: Peripheral neuropathy.
 Uncommon: Memory impairment, optic neuritis and atrophy, toxic
encephalopathy, convulsions, and toxic psychosis. Elevated serum
transaminase (SGOT SGPT), jaundice, hyperbilirubinemia, nausea, vomiting,
epigastric distress, thrombocytopenia, agranulocytosis, sideroblastic,
hemolytic, or aplastic anemia, and eosinophilia, systemic Lupus
Erythematosus, fever, lymphadenopathy, skin eruptions, vasculitis,
pyridoxine deficiency, metabolic acidosis, hyperglycemia, pellagra, and
gynecomastia.

8. NURSING RESPONSIBILTY
 Encourage the patient to eat small, frequent meals as tolerated; perform
frequent mouth care; and drink adequate fluids to ensure adequate
nutrition and hydration.
 Monitor nutrition if GI effects become a problem.
 Encourage that the patient is instructed about the appropriate dosage
regimen, use of drug combinations and possible adverse effects to
enhance patient knowledge about drug therapy and to promote
compliance.

9.  The Patient should inform:
 To drink a lot of fluids to maintain nutrition (very important)
even though nausea, vomiting and diarrhea may occur.
 To use barrier contraceptives and understand that oral
contraceptives may not be effective if antimycobacterial
drugs are being used.
 To understand that normally some of these drugs impart an
orange stain to body fluids. If this occurs, the fluids may say
stain clothing and tears may stain contact lenses.
 To report difficulty breathing, hallucinations, numbness and
tingling, worsening of condition, fever and chills or changes
in color of urine or stool to a health care provider.

10.  Evaluation:
 Monitor patient response to the drug (resolution of mycobacterial
infection).
 Monitor for adverse effects (GI effects, CNS changes and hypersensitivity
reactions).
 Evaluate the effectiveness of the teaching plan (patient can name the drug,
dosage, possible adverse effects to expect and specific measure to help
avoid adverse effects).
 Monitor the effectiveness of comfort and safety measures and compliance
with the regimen.