TB DRUGS Flashcards
Rifampicin dose
- If less than 50kg
450 mg OD - If more than 50kg
600mg OD
Rifampicin - CI
- Acute porphyrias
- Jaundice
Rifampicin - SE
Common SE:
- N + V
- Thrombocytopenia
Specific:
- Psychosis
- Flu like symptoms with intermittent therapy
- Resp e.g. SOB
- Colours soft contact lenses AND urine red/orange
Enzyme Inducer - CYP450 INTERACTION!!!!
Can Rifampicin be used in hepatic impairment?
- Should avoid or do not exceed 8mg/kg daily
- Monitor weekly for 2 weeks, then fornightly for 6 weeks
- Counsel pt to report signs of hepatotoxicty
What are the monitoring
requirements if on Rifampicin?
- Renal - before
- Hepatic - before
- fever, malaise, vomiting, jaundice
Rifampicin - counselling
- Can colour soft contact lenses
- Urine orange/red - harmless
- Empty stomach
- Report: signs of hepatotoxicity
Rifampicin - interactions
CYP enzyme inducer
- Increases enzyme activation, drugs are metabolised more = less effective
- e.g. hormonal contraception
Rifampicin - pregnancy
- Pregnancy = high doses are teratogenic in 1st trimester, increased risk of neonatal bleeding in 3rd trimester.
- BF = safe (amount too small to be harmful)
What is the dose of Isoniazid in Tuberculosis?
300mg od
What are the contraindications for use of Isoniazid?
- DILI
- Tyramine rich food
Isonazid - SE
- liver toxicity
- peripheral neuropathy
Peripheral neuropathy RF
- Diabetes
- Alcohol dependence
- Chronic renal failure
- Pregnancy
- Maltnutrition
- HIV
Isoniazid - how to take
30-60 mins before food
Isoniazid - pregnancy + BF
Pregnancy = not known to be harmful
BF = risk of convulsions and neuropathy, monitor infant for toxicity
Who is more likely to get Hepatitis with isoniazid?
- Common in those aged over 35 years old
- Those with a daily alcohol intake
What are the monitoring requirements for isoniazid?
renal/ hepatic function
What should patients taking isoniazid be counselled on with regards to hepatic disorder?
To seek medical attention if symptoms occur:
- Persistent nausea
- Vomiting
- Malaise
- Jaundice occurs
What is the dose of Pyrazinamide in
Tuberculosis?
- If less than 50kg: 1.5 g OD
- If more than 50kg: 2g OD
What are the contraindications for use of Pyrazinamide?
- Acute attack of gout in adults
In which patients should Pyrazinamide be used with caution?
- Diabetes
- Gout
What are the side-effects of
Pyrazinamide?
- Gout aggravated
- Hepatic disorders
What are the monitoring requirements for Pyrazinamide?
- Renal function
- Hepatic function
What should patients taking Pyrazinamide be counselled on?
To seek medical attention if symptoms of hepatic disorder occur:
1. Perisistent nausea
2. Vomiting
3. Malaise
4. Jaundice
What are the contraindications for use of Ethambutol?
- Optic neuritis
- Poor vision
What is the dose of Ethambutol in Tuberculosis?
15mg/kg OD
What are the side-effects of Ethambutol?
- Visual impairment
- Hyperuricaemia
- Ocular toxicity
In which patient groups is Ethambutol cautioned, provide an explanation?
- Elderly and young children
- because they may not be able to report vision changes as easily as an adult
What can increase the risk of optic nerve damage with Ethambutol?
- Overdose
- Renal impairment
What are the monitoring requirments with Ethambutol?
- Plasma-Ethambutol concentration
- Peak should be 2-6mg/L
- Trough should be less than 1mg/L - Renal function
- Before treatment - Visual activity
- Using Snellen Chart
- Before treatment
What should patients taking Ethambutol be counselled on?
- If deterioration in vision occurs, to discontinue treatment and seek medical advise
- Could be ocular toxicity which is a main side-effect
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
