internal medicine Flashcards
half lives of drugs
- 5 half lives of a new drug if no loading dose, drug level will be 97% of steady state, and same to stop drug and have it clear
first pass effect
oral drugs absorbed via GI tract and pass into the portal vein, goes to the liver for first metabolism
*these drugs require much higher oral dose to be as effective as IV
warfarin interactions increase the INR
- TMP/SMX *propafenone
- erythromycin *azole antifungals
- amiodarone *metronidazole
- any antibiotic can affect INR
as they decrease vitamin producing bacteria in the intestine
Drugs that cause hyperkalemia
- ACE/ARBs
- spironolactone & other K sparing diuretics
- heparin
- can be worse hyperK+ if these drugs are combined as in CHF tx
- *trimethoprim (Bactrim) can cause and greatest risk is use if high dose bactrim in the elderly
Statin interactions
- most life threatening reaction=rhabdomyolysis
- greatest risk is combo with drugs that slow their metabolism:
- fibrates -amiodarone
- emycin
-cyclosporine -protease inhibitors
_azole antifungals -verapamil, diltiazem
*grapefruit will markedly raise blood levels of statins
*lovastatin & simvastatin most affected
**pravastatin least affected-its metabolized by kidneys
gihydropyridines :
-nifedipine
-amlodipine
cause:
edema
constipation
SSRIs cause
hyponatremia
sexual dysfxn
may cause platelet dysfunction
Topiramate causes
non anion gap acidosis
kidney stones
HCTZ causes
hypoK+
hyper Ca++
hypo Na+
high uric acid
NSAIDS increase risk of
symptomatic CHF in pt at risk of CAD
bisphosphonates can cause
muscle and joint pain
PPIs may inhibit
antiplatelet activity of plavix
Risk factors for primary osteoporosis:
- hx of fragility fracture in 1st degree relative
- weight less than 127# or BMI<21
- alcohol intake of 2 or more drinks/day
- menopause before age 40
- current or prior steroid use: >3 months at dose of 5mg/d or more of prednisone
- smoking
- personal hx of fragility fracture
patients with the following should be screened for osteoporosis regardless of age or gender:
- GI dz: UC, crohns, celiac, gastric bypass, malabsorption
- endocrine: hyperparathyroid, cushings, hypogonad, hyperthyroid
- anorexia nervosa
- RA, SLE
- prolonged bedrest or wheelchair bound
- medications: glucocorticoids, thyroxine over replacement, lithium,phenobarbital, phenytoin, cyclosporine
3 most accurate methods of diagnosis of osteoporosis:
- quantitative CT
- dual photon absorptiometry (DPT)
- dual energy x-ray absorptiometry (DEXA)
Universal recommendations for all patients with osteoporosis:
- dietary calcium 1200-1500mg/d
- vitamin D 800-1000 IU D3 daily >age 50
- regular weight bearing exercise
- fall prevention
- avoid tobacco and excess alcohol
drug tx of osteoporosis
HRT
bisphosphonates
calcionin salmon-nasal spray
raloxifene (evista)
potential S/E of bisphosphonates
- osteonecrosis of the jaw-especially IV-caution in those with jaw problems or upcoming extensive dental surgery
- severe muscle/joint/bone pain
- Odd fractures of long bones-femur
most serious consequence of osteoporosis
fractures
mortality due to hip fractures is 20% within the first year
other complications of hip fractures
- DVT occur in 48% without anticoag. , 25% with anticoagulants
- pressure ulcers
- constipation, fecal impaction
geriatrics-diagnosis of “frailty” if 3 or more of the following are present:
- unintentional loss of 10# or more/ 1 year
- exhaustion due to lack of endurance
- decreased hand strength
- walking slowly
- reduced activity
geriatric patients need interval assessment of function which is related to longevity:
- ADLs
- instrumental ADLs
- cognition
- hearing
- vision
- gait & balance
- nutrition
- driving ability
gait & balance assessed well with timed “get up and go test”
*get up from chair, walk 10 feet, then turn around and come back to sit.. If takes >20 seconds they are high risk for falls, 10-20s is moderate risk
**performance on vision, hearing, gait assessment will give adequate assessment of pts ability to operate a vehicle
Malnutrition is diagnosed in any of these circumstances:
- unintentional wt loss of 10# or more/6 months
- BMI<3.8
- cholesterol <160
* any vitamin deficiency