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Chemotherapeutic agents
is scheduled. She states that she has successfully used
low-dose oral contraceptives for 4 years and plans to
continue this method of birth control.
CRITICAL THINKING
How do doxycyclines and some other antibiotics and
oral contraceptives interact? What are the possible
ramifications of continuing to take oral contraceptives
during a pregnancy?
What care interventions are appropriate for G.S.?
What teaching points should be stressed with G.S.? Think
about the nature of her personality and the problems
that an unplanned pregnancy might cause. How can you
help G.S. to cope with her infection, her drug regimen
and her rigorous schedule?
DISCUSSION
Several antibiotics, including tetracycline, are known to
lead to the failure of oral contraceptives as evidenced
by breakthrough bleeding and unplanned pregnancy.
Although the exact way in which these drugs interact is
incompletely understood, it is thought that the antibiotics
destroy certain bacteria in the normal flora of the gastro
intestinal (GI) tract. These bacteria are necessary for
the breakdown and eventual absorption of the female
hormones contained in the contraceptives. The 5 days
of antibiotic treatment together with the time necessary
for rebuilding the normal flora can be long enough for
the hypothalamus to lose the negative feedback signal
provided by the contraceptives that prevents ovulation
and preparation of the uterus. Sensing the low hormone
levels, the hypothalamus releases gonadotropin-releasing
hormone, which leads to the release of follicle-stimulating
hormone and luteinising hormone, with subsequent
ovulation.
G.S. will need a clear explanation and follow-up in
written form about the risks of oral contraceptive failure
while she is receiving doxycycline therapy. She should
be encouraged to use an additional form of birth control
during the course of her antibiotic use and to read all of
the literature that comes with oral contraceptives, as well
as teaching information that should be provided with the
antibiotic.
G.S. also may need a great deal of support and
encouragement at this time. The sinus infection may increase
her stress by interfering with her ability to stick to her
rigid schedule. Discussing the possibility of an unplanned
pregnancy may cause even more stress. The health clinic
visit could be used as an opportunity to allow G.S. to talk, to
vent any frustrations and stress, and then to encourage her to
make time for herself. The nurse should stress the importance
of a good diet, which will ensure that her body has the
components she will need to fight this infection, to heal and
to ward off other infections, as well as the importance of
adequate rest and exercise. The nurse should also make sure
that G.S. is receiving annual gynaecological examinations and
has been advised not to smoke.
All healthcare professionals who are involved with G.S.
should consider the impact that an unplanned pregnancy
could have on this very organised woman and use this as an
example of the importance of clear, concise teaching in the
administration of drug therapy.
CARE GUIDE FOR G.S.: TETRACYCLINES
Assessment: History and examination
Allergy to any doxycycline
Hepatic or renal dysfunction
Pregnancy or breastfeeding
Concurrent use of oral contraceptives, antacids, iron
products, digoxin or penicillins
General: site of infection, culture and sensitivity
Skin: colour, lesions
Respiratory: respiration, adventitious sounds
GI: liver evaluation, bowel sounds, usual output
Laboratory data: liver and renal function tests, urinalysis
Implementation
Perform culture and sensitivity tests before beginning
therapy.
Administer drug on an empty stomach, 1 hour before or
2 to 3 hour after meals. Do not give with antacids, milk
or iron products.
Do not use outdated drug because of the risk of
nephrotoxicity.
Monitor for and provide hygiene measures and treatment
if superinfections occur.
Monitor nutritional status and fluid intake.
Provide ready access to bathroom facilities if diarrhoea is a
problem.
Provide support and reassurance for dealing with the drug
effects and infection.
Provide teaching regarding drug name, dosage, adverse
effects, precautions, warnings to report and drugs that
might cause a drug–drug interaction, including the
need to use a second form of contraception if using oral
contraceptives.
Evaluation
Evaluate drug effects: resolution of bacterial infections.
Monitor for adverse effects: GI effects, superinfections,
CNS effects.
Monitor for drug–drug interactions: lack of effectiveness
of oral contraceptives, lack of antibacterial effect with
antacids or iron.
Evaluate effectiveness of teaching program.
Evaluate effectiveness of comfort and safety measures.
Teaching for G.S.
• Doxycycline is an antibiotic that is specific for your infection.
You should take it throughout the day for best results.
