60 DRUGS IN THE ELDERLY
4.Use the fewest possible number of drugs the patient needs.
5.Consider the potential for drug interactions and
co-morbidity on drug response.
6.Drugs should seldom be used to treat symptoms without
first discovering the cause of the symptoms (i.e. first
diagnosis, then treatment).- Drugs should not be withheld because of old age, but it
should be remembered that there is no cure for old age
either.
8.A drug should not be continued if it is no longer necessary.
9.Do not use a drug if the symptoms it causes are worse
than those it is intended to relieve. - It is seldom sensible to treat the side effects of one drug
by prescribing another.
In the elderly, it is often important to pay attention to mat-
ters such as the formulation of the drug to be used – many old
people tolerate elixirs and liquid medicines better than tablets
or capsules. Supervision of drug taking may be necessary, as
an elderly person with a serious physical or mental disability
cannot be expected to comply with any but the simplest drug
regimen. Containers require especially clear labelling, and
should be easy to open – child-proof containers are often also
grandparent-proof!
RESEARCH
Despite their disproportionate consumption of medicines, the
elderly are often under-represented in clinical trials. This may
result in the data being extrapolated to an elderly population
inappropriately, or the exclusion of elderly patients from new
treatments from which they might benefit. It is essential that,
both during a drug’s development and after it has been licensed,
subgroup analysis of elderly populations is carefully examined
both for efficacy and for predisposition to adverse effects.Initial laboratory results revealed that the patient had
acute on chronic renal failure, dangerously high potassium
levels (7.6 mmol/L) and anaemia (Hb 7.4 g/dL). Emergency
treatment included calcium chloride, dextrose and insulin,
urinary catheterization, furosemide and haemodialysis.
Gastroscopy revealed a bleeding gastric ulcer. The patient
was discharged two weeks later, when he was symptomat-
ically well. His discharge medication consisted of regular
doxazosin and ranitidine, and paracetamol as required.
Question
Describe how each of this patient’s drugs prescribed before
admission may have contributed to his clinical condition.
Answer
Co-amilozide – hyperkalaemia: amiloride, exacerbation of
prostatic symptoms: thiazide
Chlorpromazine – urinary retention
Ketoprofen – gastric ulcer, antagonism of thiazide diuretic,
salt retention, possibly interstitial nephritis
Magnesium trisilicate mixture – additional sodium load
(6 mmol Na/10 mL).
Comment
Iatrogenic disease due to multiple drug therapy is common
in the elderly. The use of amiloride in renal impairment
leads to hyperkalaemia. This patient’s confusion and rest-
lessness were most probably related to his renal failure.
Chlorpromazine may mask some of the symptoms/signs and
delay treatment of the reversible organic disease. The anal-
gesic of choice in osteoarthritis is paracetamol, due to its
much better tolerance than NSAID. The sodium content of
some antacids can adversely affect cardiac and renal failure.NON-STEROIDAL ANTI-INFLAMMATORY DRUGSThe elderly are particularly susceptible to non-steroidal anti-
inflammatory drug (NSAID)-induced peptic ulceration, gastro-
intestinal irritation and fluid retention. An NSAID is frequently
prescribed inappropriately for osteoarthritis before physical
and functional interventions and oral paracetamolhave been
adequately utilized. If an NSAID is required as adjunctive
therapy, the lowest effective dose should be used. Ibuprofen
is probably the NSAID of choice in terms of minimizing gas-
tro-intestinal side effects. A proton pump inhibitor should be
considered as prophylaxis against upper gastro-intestinal
complications in those most at risk.
PRACTICAL ASPECTS OF PRESCRIBING
FOR THE ELDERLYImproper prescription of drugs is a common cause of morbid-
ity in elderly people. Common-sense rules for prescribing do
not apply only to the elderly, but are especially important in
this vulnerable group.
- Take a full drug history (see Chapter 1), which should
include any adverse reactions and use of over-the-counter
drugs.
2.Know the pharmacological action of the drug employed.
3.Use the lowest effective dose.
Case history
A previously mentally alert and well-orientated 90-year-old
woman became acutely confused two nights after hospital
admission for bronchial asthma which, on the basis of peak
flow and blood gases, had responded well to inhaled salbu-
tamol and oral prednisolone. Her other medication was
cimetidine (for dyspepsia), digoxin (for an isolated episode
of atrial fibrillation two years earlier) and nitrazepam (for
night sedation).
Question
Which drugs may be related to the acute confusion?
Answer
Prednisolone, cimetidine, digoxin and nitrazepam.
Comment
If an H 2 -antagonist is necessary, ranitidine is preferred in the
elderly. It is likely that the patient no longer requires digoxin
(which accumulates in the elderly). Benzodiazepines should
not be used for sedation in elderly (or young) asthmatics.
They may also accumulate in the elderly. The elderly tend to
be more sensitive to adverse drug effects on the central ner-
vous system (CNS).