INH drug 'Isoniazid'
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Transcript of INH drug 'Isoniazid'
Isoniazid
Prepared by: Nahry Omer Muhammad
Contents • Introduction
• Mechanism of action
• Pharmacokinetics
• Dosage and Administration
• Contraindications
• Drug Interactions
• Adverse Reactions/Side effects
• Precautions
• Overdosage
• Patient Information
Synonyms and Abbreviations
• Isonicotinyl hydrazine
• Isonicotinic acid hydrazide
• INH
• H (for "hydrazide", and also the WHO standard abbreviation)
Trade Name • Nydrazid:
-Injection: 100mg/ml
• Isoniazid - Tablets 100 mg - Tablets 300 mg - Tablets 500 mg - Syrup 50 mg/5 mL
• Isotamine
• Laniazid
• first-line medication in prevention and treatment of Tuberculosis.
• Synthesized in the early 20th century.
• Isoniazid is available in tablet, syrup, and injectable forms (given intramuscularly or intravenously).
• Isoniazid is manufactured from isonicotinic acid, which is produced from 4-methylpyridine.
Isoniazid
CLASSIFICATION OF DRUGS USED IN ANTI-TUBERCULOSIS TREATMENT
• ISONIAZIDE
• RIFAMPIN
• PYRAZINAMIDE
• ETHAMBUTOL
• STREPTOMYCIN
• AMIKACIN
• AMINOSALICYCLIC ACID
• CAPREOMYCIN
• CIPROFLOXACIN
• CLOFAZIMINE
• CYCLOSERINE
• ETHIONAMIDE
• LEVOFLOXACIN
• RIFABUTIN
• RIFAPENTINE
FIRST LINE DRUGS SECOND LINE DRUGS
MECHANISM OF ACTION
• Inhibit synthesis of Mycolic acid.
• It’s a pro drug activated by KatG.
• Resistance to INH is associated with overexpression of inhA.
• Overproducers of inhA express low level INH resistance & cross resistance to ethionamide.
• KatG mutants express high level of INH resistance & usually no cross resistance to ethionamide.
Pharmacokinetics
• Absorption: T max is 1 to 2 h.
• Distribution: Diffuses readily into cerebrospinal, pleural,
and ascitic fluids, tissues, organs, saliva, sputum, feces, placental barrier, and in breast milk.
• Metabolism: Primarily by acetylation and
dehydrazination.
• Elimination: 50% to 70% excreted in the urine in 24 h.
Dosage and Administration • Tuberculosis:
Adults
• PO / IM 5 mg/kg/day as single daily dose (max, 300 mg/day) or 15 mg/kg 2 to 3 times/wk (max, 900 mg).
• Infants and Children
• PO / IM 10 to 20 mg/kg/day in single daily dose (max, 300 mg/day) or 20 to 40 mg/kg 2 or 3 times/week (max, 400 mg).
Contraindications • Previous isoniazid-associated hepatic injury
• Drug fever
• Chills
• Arthritis
• Acute liver disease.
• Pregnant women.
• Breast feeding women
Drug Interactions • Aluminum salts
• Carbamazepine
• Disulfiram
• Enflurane
• Hydantoins
• Rifampin
Adverse Reactions • CNS: Peripheral neuropathy; convulsions; toxic encephalopathy; optic
neuritis and atrophy; memory impairment; toxic psychosis.
• Dermatologic: Morbilliform, maculopapular, purpuric, or exfoliative skin
eruptions.
• GIT: Nausea; vomiting; epigastric distress.
• Hematologic: Agranulocytosis; hemolytic, sideroblastic, or aplastic
anemia; thrombocytopenia; eosinophilia.
• Hepatic: Hepatotoxicity, including elevated serum transaminase levels,
bilirubinemia, bilirubinuria, jaundice, severe and sometimes fatal hepatitis.
• Metabolic: Pyridoxine deficiency; pellagra; hyperglycemia; metabolic
acidosis; hypocalcemia; hypophosphatemia.
• Miscellaneous: Gynecomastia; rheumatic syndrome; systemic lupus
erythematosus-like syndrome; local irritation at IM injection site.
Precautions • Pregnancy
• Lactation
• Hypersensitivity
• Renal Function
• Hepatic Function
• Pyridoxine administration
Overdosage Symptoms:
Nausea, vomiting.
dizziness, slurring of speech.
blurring of vision, visual hallucinations.
respiratory distress, CNS depression.
stupor, coma.
severe seizures (Diazepam (Valium), 5 to 10 mg).
Patient Information • Advise patient to minimize daily alcohol consumption while
taking isoniazid because of the increased risk of hepatitis.
• Instruct patient to report the following symptoms to health care provider: weakness; fatigue; loss of appetite; nausea and vomiting; yellowing of skin or eyes; darkening of urine; numbness or tingling in hands or feet.
• Emphasize to patient that treatment will be lengthy and that patient must complete entire course of therapy. Relapse of tuberculosis is higher if chemotherapy is discontinued prematurely.
• Advise patient to return for laboratory follow-up.
• Caution patient not to perform activities that require mental alertness if adverse CNS symptoms occur.
Referneces: • Katzung & Trevor’s Pharmacology/Examination &
Board Review/Sixth edition 2002
• www.drugs.com
• www.wikipedia.org
• www.dictionary.reference.com
• www.webmd.com
• www.fda.gov
• www.floridarehab.com
Thank You