C H A P T E R 4
Clinical decision making in drug therapy
45
for evaluating the effectiveness of the drug and the
occurrence of any adverse effects. Relevant aspects of
the person’s physical examination specifically related to
drug therapy are discussed in the following text.
Weight
A person’s weight helps to determine whether the rec-
ommended drug dose is appropriate. Because the
recommended dose typically is based on a 70-kg adult
man, people who are much lighter or much heavier often
need a dose adjustment.
Age
People at the extremes of the age spectrum—children
and older adults—often require dose adjustments
based on the functional level of the liver and kidneys
and the responsiveness of other organs. The child’s
age and developmental level will also alert the health-
care provider to possible problems with drug delivery,
such as the ability to swallow pills or follow directions
related to other delivery methods. The child’s develop-
mental age will also influence pharmacokinetics and
pharmacodynamics; the immature liver may not metab-
olise drugs in the same way as in the adult or the kidneys
may not be as efficient as those of an adult. As people
age, the body undergoes many normal changes that can
affect drug therapy, such as a decreased blood volume,
decreased gastrointestinal (GI) absorption, reduced
blood flow to muscles or skin and changes in receptor-
site responsiveness. Older adults often have a variety
of chronic medical conditions and can be receiving a
number of medications that need to be evaluated for
possible interactions. Older adults with various central
nervous system disorders, such as Alzheimer’s disease or
Parkinson’s disease, may develop difficulty swallowing
and might require liquid forms of medication. Through-
out this book, Drug Therapy Across the Lifespan
features present information related to the drug class
being discussed as it pertains specifically to children,
adults and the older adult population. These boxes high-
light points that the nurse and midwife should consider
to assure safe and effective therapy in each age group.
Physical parameters related to disease or drug effects
The specific parameters that need to be assessed depend
on the disease process being treated and the expected
therapeutic and adverse effects of the drug therapy.
Assessing these factors before drug therapy begins
provides a baseline level to which future assessments can
be compared to determine the effects of drug therapy.
For example, if a person is being treated for chronic
pulmonary disease, their respiratory status and reserve
need to be assessed, especially if a drug is being given
that is known to affect the respiratory tract. In contrast,
a thorough respiratory evaluation would not be war-
ranted in a person with no known pulmonary disease
who is taking a drug with little or no known effects on
the respiratory system. The nurse or midwife has the
greatest direct and continued contact with the person
and is in the best position to detect minute changes that
ultimately determine the course of drug therapy—ther-
apeutic success or discontinuation because of adverse or
unacceptable responses.
Identifying health problems
Information gathered during assessment is analysed to
arrive at some conclusions that lead to a particular goal
and set of interventions. Healthcare priorities reflect
identified alterations in a person’s function based on
the assessment of the clinical situation. Because drug
therapy is only a small part of the overall person’s situ-
ation, priorities that are related to drug therapy must be
incorporated into a total picture of the person.
Implementation
involves taking the information
gathered and synthesised to plan care. This process
includes setting goals and desired outcomes to assure
safe and effective drug therapy. These outcomes usually
involve ensuring effective response to drug therapy,
minimising adverse effects and understanding the drug
regimen. Three types of interventions are frequently
involved in drug therapy: drug administration, provision
of comfort measures and education of the person and
their family.
Proper drug administration
Nurses and midwives must consider a series of points,
or “rights”, to ensure safe and effective drug admin-
istration. These are correct drug and person, correct
storage of drug, correct and most effective route, correct
dose, correct preparation, correct timing and correct
recording of administration. See the later section on the
prevention of medication errors for a detailed explana-
tion of the nurse’s and midwife’s role in implementing
these rights. Remembering to review each point before
administering a drug will help to prevent medication
errors and improve care outcomes.
Medications:
The Three Checks and the Five Rights
of Medication Administration
Safe medication administration
Review the monographs in a drug guide or handbook
for specific parameters to be assessed in relation to the
particular drug being discussed. This assessment provides
not only the baseline information needed before giving that
drug, but also the data required to evaluate the effects of
that drug on the person. This information should supplement
the overall assessment of the person, which includes social,
intellectual, financial, environmental and other factors.
