710
P A R T 8
Drugs acting on the cardiovascular system
R.A. stabilised rapidly and was given IV fluids to
dilute the drug effects and encourage excretion. His PVCs
became less and less frequent, and he remained in normal
sinus rhythm. R.A. should be questioned about how and
when he takes his drug and any other drugs he might be
taking. He should also be reminded that antihistamines
should be avoided while on digoxin. Because he was
self-medicating with antihistamines, it is possible that
the toxicity that developed was a drug–drug interaction.
He should be encouraged to try increased fluid intake,
use a room humidifier and possibly use a non-steroidal
anti-inflammatory drug for pain relief to get through the
cold that he experienced. Before leaving, he should have
drug information reviewed to increase its safe use. He
should take the drug twice a day and not skip any doses.
If he does miss a dose, he should not catch up doses, but
should just resume the regular schedule. He should avoid
antihistamines, as well as other antiarrhythmics, while on
this drug. It is a good idea to keep a complete list of drugs
being taken—including over-the-counter drugs and herbal
remedies—so the healthcare provider can check and make
sure that there is no potential reaction to be concerned
about. He should also be reminded about the importance
of regular medical follow-up, which will include an
electrocardiogram and blood tests, to evaluate the effects
of the drug on his body.
While R.A. is within the healthcare system, it would
be a good idea to do a full electrocardiogram and to get
blood tests to measure his creatinine levels, as well as serum
electrolytes, which have an effect on cardiac conduction.
CARE GUIDE FOR R.A.: DIGOXIN
(ANTIARRHYTHMIC AGENTS)
Assessment: History and examination
Assess the person’s health history for allergies to digoxin;
for any heart block or prolonged QT intervals; history
of atrial fibrillation, including onset of last episode; and
drug history for use of antihistamines, drugs that could
prolong the QT interval, other antiarrhythmics or tricyclic
antidepressants.
Focus the physical examination on the following areas:
Cardiovascular: blood pressure, pulse, heart rhythm,
perfusion
Neurological (CNS): orientation, affect, reflexes
Respiratory system: respiratory rate and character,
adventitious sounds
Laboratory tests: renal function tests, serum electrolytes,
electrocardiogram
Implementation
Continually monitor cardiac rhythm when initiating or
changing dose.
Ensure that emergency life support equipment is readily
available.
Establish safety precautions, including side rails, lighting and
noise control, if CNS effects occur.
Arrange for periodic monitoring of cardiac rhythm when
the person is receiving long-term therapy
.
Provide comfort measures, including small, frequent
meals to minimise nausea and vomiting; access to
bathroom facilities; and environmental controls, such
as temperature regulation, light control and decreased
noise.
Offer support and encouragement to help the person deal
with the diagnosis and the drug regimen.
Provide teaching regarding drug name, dosage, schedule of
administration, measures to reduce adverse effects, other
drugs to avoid, what to report, and the need for regular,
periodic monitoring.
Evaluation
Monitor response to the drug (stabilisation of cardiac
rhythm and output).
Monitor for adverse effects (sedation, hypotension, cardiac
arrhythmias, respiratory depression, CNS effects).
Monitor for drug–drug interactions.
Evaluate the effectiveness of the teaching plan (person
can name drug, dosage, adverse effects to watch for,
specific measures to avoid them, and the importance
of continued follow-up).
Monitor the effectiveness of comfort measures and
compliance with the regimen.
TEACHING FOR R.A.
• An antiarrhythmic drug, such as digoxin, acts to stop the
irregular rhythm in your heart, helping it to beat more
regularly and therefore more efficiently.
• When taking digoxin, you should remember to take it
twice a day. If you miss a dose, do not make up the dose,
just return to your regular schedule. Never take more than
two doses in a day.
• Do not take antihistamines while you are on this drug;
this combination can increase the adverse effects
and can be quite serious. There are other drugs that
should be avoided; make sure you give your healthcare
provider a complete list of the drugs that you are
taking, including over-the-counter drugs and herbal
remedies, so the safety of any combinations can be
checked.
• Some adverse effects that might occur include the
following:
•
Headache
: Medication may be available to help if this
is a problem.
•
Dizziness, light-headedness
: Avoid driving a car or
operating dangerous machinery until you know how
this drug will affect you.
•
Nausea, diarrhoea, flatulence
: Small, frequent meals may
help to alleviate these problems.
