Clinical pharmacology of old age Flashcards
(17 cards)
What is pharmacokinetics?
How the body interacts with administered substances for the entire duration of exposure
Proportionally more of basic drugs are absorbed in older patients than in younger patients. True/false?
True
As people age, there is increased gastric pH (decreased acid) and small bowel surface area decreases. When would this usually be a problem?
Previous GI surgery
NJ tube or PEG feed composition
Transdermal patches and oedema
Older patients have decreased fat (proportional to muscle mass). true/false?
False
Increased fat, this increases the vd pf lipophyllic drugs e.g. diazepam which results in longer half lives.
What is Vd (volume of distribution)?
Theoretical volume into which all of drug is fully dissolved in plasma
It is an indicator of the lipophilicity of a drug (very lipophilic = high Vd)
Meaning of half-life?
Time for drug concentration to fall to half of it’s maximum concentration
Roughly what % of body water decreased with age?
10-15%
Why does liver function decrease with age?
Occurs due to decreased liver size, blood flow and disease
Why does GFR decrease with age?
This occurs due to decreased size, tubular secretion and renal blood flow
What are the 4 main drugs associated with adverse reactions in the elderly?
Warfarin
Digoxin
Insulin
Benzodiazepines
What side-effect is frequently caused by opiates in elderly and how is this prevented?
Opiates frequently causes constipation - begin laxatives prophylactically
If steroids are used what needs to be given if used long term and what other condition can it lead to?
Osteoporosis prevention if used long term
Can lead to steroid induced diabetes
What can interfere with the absorption of levothyroxine?
Calcium
What can opioids and be benzodiazepines lead to?
Impaired psychomotor function which would result in falls and confusion.
Risk factors for adverse drug reaction in older patient?
Recent hospital discharge
Use of multiple drugs
Multiple prescribers
A change in the patients condition
Impaired cognitive status and /or communication problems
What are some options for reducing polypharmacy?
Review medications and indications regularly, discontinue unnecessary medications
If stable, consider use of combination preparations
Attempt to prescribe a drug that would treat more than 1 existing problem (e.g. calcium channel blocker/beta blocker for increased BP and angina)
Avoid treating adverse reactions/side-effects of drug with more drugs (e.g. amlodipine leading to oedema).
Is adherence to medication a major problem in the elderly and what specific issues can arise?
Can they open pill container?
Do they understand when and how to take it?
Are they remembering to take medications?
