Tdm Drugs Flashcards
Which foods interact with warfarin
Vitamin k- green tea, green vegetables
Pomegranate juice
Alcohol
Patients on warfarin should report nose bleeds lasting longer than…
10 mins
Inr target for warfarin
Normally 2-3.5
Risks of warfarin
Calciphylaxis
Haemorrhage
Avoid 48 hours post partum
Wocbp- teratogenic
Interaction of warfarin
Doacs to treat hepatitis C
Monitor for warfarin
LFT FBC clotting screen before start
Lithium target
0.4-1 mmol/L
Monitoring for lithium
Serum conc
Renal function, electrolytes
ECG
Fbc
Tfts
Bmi
If lithium serum function is over 2
Seizures, coma, renal failure, arrhythmia, bp changes, circulatory failure
Monitor symptoms of lithium toxicity like
Gi visual and cns disturbance
Tremor, muscle weakness
Hypothyroidism, renal dysfunction, benign intracranial hypertensikn
Important interactions of lithium
Antispychotics- increase EPS
Increased risk of toxicity- ACEi, ARB, loop diuretics, k sparing diuretics, nsaids, thiazide like diuretics, SSRI, metronidazole (hyperkalaemia)
Neurotoxicity- methyldopa, phenytpin, carbemazepine, diltiazem, verapamil
Lithium when dispensing
Ensure same brand as normal
Adequate salt and water intake essential
Dioxin target conc
1-2mcg/l
Dioxin electrolyte imbalances
Decreases k
Decreases mg
Increases calcium
Monitoring digoxin
Electrolytes
Renal function
Hr
Amiodaeone with digixin
Decrease dioxin dose by half
Which drugs increase digoxin levels
Diltiazem verapamil nifedipine
Quinine
Spironolactone
Which drugs reduces conc of digoxin
St John’s wort
Which drugs increase risk of digixin toxicity
Nephrotoxic drugs and those that cause hypokalamia
Warnings of digoxin toxicity
Arrhythmia heart block ❤️
Neurological signs-weakness, lethargy, dizziness, headache, confusion, psychosis
Gi- anorexia, n&v , diargoea, abdo pain
Visual- blurred/ yellow vision
Theophylline target levels
10-20 mg/L
Or 55-110mcmol/L
theophylline toxicity looks like
Vomiting, throwing up blood, agitation, restlessness, dilated pupils, tachycardia, arrythmias hyperglycaemia, severe hypokalaemia, convulsions,
Counselling for theophylline
Check with hcp before taking new medication
Inform gp if stop or start smoking
Maintain same brand
What should you monitor with theophylline
Potassium levels
Plasma theophylline levels
Interactions of theophylline
Hypokalaemia- beta 2 agonists, corticosteroids, diuretics
Increased concentration- diltiazem, verapamil cimetidine, ciprofloxacin, estrogen, erythromycin
Increased risk of convulsions with quinolones
Reduced theophylline concs with carbazepine, phenytoin
What do you monitor with methotrexate
Fbc
Renal
Liver
Antidote to methotrexate
Folinic acid
Methotrexate causes
Blood dyscrasias- bone marrow supression
Gi toxicity- stomatitis
Liver toxicity
Pulmonary toxicity- pneumonitis, cough, sob
Teratogenicity- contraception for 6 mo
Interactions of methotrexate
Acitretin- hepatotoxicity
Nsaids and penicillin reduce excretion of methotrexate
Increased toxicity with doxycycline, tetracycline, cuprofloxacin, PPIs
Trimethoprim- haematological toxicity
Which otcs need to be avoided with methotrexate
Nsaids and aspirin
Counselling points methotrexate
Photosensitivity
Once a week, take folic acid a different day
Target conc phenytoin
10-20mg/L
What we monitoring for phenytoin
Serum conc
Ecg and BP
LFT
FBC
folate and vitamin d
Phenytoin toxicity looks like
Rem of eyes, difficult balancing, slurred speech, hyperglycaemia, double vision, blurred vision, confusion
Warnings for phenytoin
Skin disorders- rash, toxicity epidermal necrolysis
Blood disorders- fever, sore throat, bruising
Suicidal thoughts
Low vitamin d
Interactions of phenytoin
Increased levels- amiodarone , diltiazem, fluconazole, miconazole, trimethoprim, metronidazole, clarithromyxin,
Reduced levels- rifampicin, St John’s wort, theophylline, itraconazole, ciclosporin
Ciclosporin councelling
- Maintain specific brand
- avoid live vaccines
- avoid UV
- Avoid high k and grapefruit juice
Monitoring for ciclosporin
Fbc
Electrolytes- k, mg
LFTs
Renal
Lipids
Bp
Toxicity types ciclosporin
Neurotoxicity- tremor, headache, encephalopathy, drowsy
Blood toxicity- infection, sore throat, bleeding
Liver toxicity
Nephrotoxicity
Tachycardia and hypertension
Interactions with ciclosporin
Increased conc- grapefruit juice, antifungal, diltiazem, clarithromycin, erythromycin,
Reduced conc- carbemazepine, orlistat, phenobarbital, phenytoin, rifampicin, St John’s wort