TB Drugs: Flashcards
RIPE (1st line drugs)=
Rifampin/rifapentine
Isoniazid
Pyrazinamide
Ethambutol
Isoniazid (INH) :
MOA
Inhibits bacterial cell wall synthesis
Bactericidal
Indicated in adults and peds for TB treatment and prevention
Contraindicated in patients with acute liver disease
Take on empty stomach
Preg cat C
P450 2C9 inhibitor
Drug interactions: antacids, carbamazepine, phenytoin, ketoconazole, theophylline, valproate, BZDs, warfarin
Isoniazid ARDs:
Peripheral neuropathy most common
Dose-related
Most often in malnourished, diabetes, EtOH
Elevated LFTs
10% - 20% usually within first 3 months of treatment
Sometimes progresses to jaundice and fatal hepatitis
Prodrome: anorexia, N/V, fatigue, malaise, weakness
Pyridoxine (vit B6) deficiency
N/V
Less common: agranulocytosis, SLE-like syndrome, fever
Isoniazid (INH) side effects:
INH
Intestinal upset
Neuropathy
Hepatotoxicity
INH intoxication:
Overdosage N/V, dizziness, speech slurring, vision blurring, hallucinations Respiratory distress CNS depression (stupor to profound coma) Seizures Severe metabolic acidosis hyperglycemia
Rifampin:
Class: Rifamycin MOA: Inhibits DNA-dependent RNA polymerase Bactericidal Highly lipophilic Spectrum: M. tb, N. meningitidis, M. leprae, MRSA, Staph epi. Indications Tuberculosis Meningococcal carriers Not meningitis due to resistance Dose for 2 days Used in kids and adults
Rifampin ADRs:
*Red-orange body fluids GI: heartburn, anorexia, N/V, jaundice, flatulence, cramps, diarrhea, CDAD Thrombocytopenia HA, fever, drowsiness, fatigue, ataxia, dizziness Visual disturbances Dysmenorrhea Hyperuricemia Pruritus, urticaria, rash, Stevens-Johnson, TEN
Rifampin DIs:
STRONG 3A4 inducer Oral contraceptives Warfarin Ketoconazole SMX-TMP INH
Rifapentine:
MOA
inhibits DNA-dependent RNA polymerase in susceptible strains ofM. tuberculosisbut not mammalian cells
Bactericidal
Used with INH for patients 12 yo and older
Not for pregnancy, HIV, kids under 2, resistant M.tb
Induces 3A4, 2C9
Rifapentine:
Hepatotoxicity, hyperbilirubinemia, colored body fluids, CDAD
≥10%: hyperuricemia, pyuria, hematuria, UTI, proteinuria, lymphopenia, neutropenia, anemia, and hypoglycemia
Pyrazinamide:
Nicotinamide (vitamin B3) analog
Indicated for treatment of active TB in adults and children
Contraindicated in gout or severe liver disease
Half-life 9 – 10 hours
Prolonged in renal/liver impairment
Excreted in urine
Pyrazinamide ADRs:
Hyperuricemia Inhibits renal excretion of uric acid Increased LFTs Rash Arthralgias, myalgias
Ethambutol
MOA: inhibits metabolite synthesis, impairing cell metabolism, stopping reproduction
Only useful for mycobacteria
*Used for adjunct treatment of tb
*Not used as monotherapy
Contraindicated in optic neuritis
Drug interactions: Al-containing antacids
Ethambutol ADRs:
Decreased visual acuity, optic neuritis, optic neuropathy,
Patients should report any visual change
Hyperuricemia, arthralgias, GI, confusion, disorientation
Bedaquiline:
First new drug for TB in 40 years Approved 2012 MOA: inhibits mycobacterial ATP synthase *Indicated in combo tx for MDR TB QT prolongation Increased risk of death (11.4%, 4x placebo in once study) Hepatotoxicity CYP 3A4 substrate ADRS: nausea, arthralgia, HA Preg cat B