TUBERCULOSIS Flashcards
Phases of treatment
Treatment is split into 2 phases:
Initial phase
- 2 months
- 4 drugs
Continuation phase (4 months)
- 4 months
- 2 drugs
Initial phase
- Rifampicin
- Isoniazid
- Pyrazinamide
- Ethambutol
2 months
RIPE
Continuation phase
- Rifampicin
- Isoniazid
4 months
Latent TB
3 months of rifampicin + isoniazid or 6 months of isoniazid
Vitamin B6 pyridoxine in conjunction – for peripheral nephropathy
who would you give unsupervised regimen to
people who are likely to take anti-TB drugs reliably and willingly without supervision
who would you give supervised regimen (aka directly observed therapy DOT) to
- non-adherence
- previous treatment for TB
- homelessness, drug or alcohol misuse
- in prison or young offender, or have been in past 5 yrs
- major psychiatric, cognitive or memory disorder
a 23 year old man has tuberculosis and you are in charge of his regimen. you are looking into whether you should give supervised DOT or unsupervised. he seems adherent, is not in denial of his diagnosis, and has no psychiatric, cognitive or memory disorder. he is not in prison, however he was in a young offender institution 3 years ago for 12 months. what do you offer him
offer DOT because he was in a prison in the past 5 years
with supervised treatment, the preferred option is ….. but a …….. schedule can be considered in individuals with TB if they require enhances case management and daily DOT therapy is not available
Daily supervised treatment is the preferred option wherever feasible.
A 3 times weekly dosing schedule can be considered in individuals with TB if they require enhanced case management and daily directly observed therapy is not available.
Vitamin B6 pyridoxine
peripheral nephropathy
Hepatotoxicity
Patients with latent TB aged 35 - 65 years should be cleared of hepatotoxicity
Rifampicin side effects
Common SE:
- N + V
- Thrombocytopenia
Specific:
- Psychosis
- Flu like symptoms with intermittent therapy
- Colours soft contact lenses AND urine red/orange
Enzyme Inducer - CYP450 INTERACTION!!!!
rifampicin is an enzyme… which means
inducer
so it can decrease the exposure of other drugs that are metabolised by CYP enzymes
a patient who takes rifampicin comes to the pharmacy and complains of persistent nausea, vomiting, malaise and jaundice. what do you do
stop treatment and seek immediate medical attention
hepatic disorder
rifampicin - 3 labels
do not stop taking unless dr says
may colour urine, harmless
take on empty stomach - 1 hour before or 2 hours after food
Rifampicin - hepatic impairment
Caution
Dose reduction - max 8 mg/kg/day
Monitor weekly for 2 weeks, then fornightly for 6 weeks
Counsel pt to report signs of hepatotoxicty
Rifampicin - Pregnancy + BF
Rifampicin = enzyme inducer = reduced efficacy of oral contraceptives (recommend IUD)
Pregnancy = high doses are teratogenic in 1st trimester, increased risk of neonatal bleeding in 3rd trimester.
BF = safe (amount too small to be harmful)
Isoniazid
- Contraindicated in drug induced liver disease
- Enzyme Inhibitor - CYP450 INTERACTION!!!!
- Avoid tyramine rich food or histamine- rich food
- Monitor liver function
Isoniazid - peripheral neuropathy
Pyridoxine given to prevent this SE.
More likely to occur with risk factors:
- Diabetes
- Alcohol dependance
- Renal failure
- Pregnancy
- HIV
hepatitis with isoniazid is more common in
pt ages over 35 and those with daily alcohol intake
isoniazid instructions - with food or before food or after food
30-60 mins before food
Risk of peripheral neuropathy
- Diabetes
- Alcohol dependance
- Renal failure
- Pregnancy
- HIV
Isoniazid - pregnancy + BF
Pregnancy = not known to be harmful
BF = risk of convulsions and neuropathy, monitor infant for toxicity
Pyrazinamide
- Contraindicated in acute attacks of gout
- Hepatotoxic
- Monitor renal and hepatic function
Pyrazinamide - contraindications
Gout
Pyrazinamide - Pregnancy + BF
Pregnancy = only use if risk outweighs benefit
BF = amount too small to be harmful
Ethambutol
- Visual Impairment + Ocular Toxicity
- Contraindicated in optic neuritis and poor vision
- Avoid in children as they cannot report signs of visual impairment
- TDM peak 2-6mg/L and trough less than 1mg/L
Ethambutol - contraindications
Optic neuritis
Poor vision
Ethambutol - ocular toxicity
Counsel patient to report visual changes.
More common in high doses or renal impairment
Early discontinuation = recovery of eyesight
will early discontinuation of ethambutol recover eyesight
Early discontinuation of the drug is almost always followed by recovery of eyesight.
Side effects - GENERAL
Liver toxicity = rifampicin, isoniazid + pyrazinamide
Peripheral neuropathy = isoniazid
Ocular toxicity = ethambutol
Orange/red secretions = Rifampicin
RIPE - with ones are hepatotoxic and which one is oculotoxic
RIP - hepatotoxic
E - oculotoxic
