PENICILLIN AND DRUG-DRUG INTERACTIONS
Penicillin can produce adverse effects if it is administered in conjunction with
other drugs. This is the situation with giving penicillin with an anti-hypertensive
such as Captopril (angiotensin-converting enzyme [ACE] inhibitors), potassium-
sparing diuretics such as Aldactone, potassium-containing drugs, or potassium
supplements such as Kay Ciel. The combination of drugs may increase the
patient’s potassium level (hyperkalemia) and therefore require that the patient’s
serum potassium levels be carefully monitored while the patient receives penicillin.
There is an increased risk of bleeding when administering high doses of par-
enteral carbenicillin or ticarcillin as these drugs inhibit platelet aggregation.
These penicillins also increase the risk for severe bleeding if given with throm-
bolytic agents such as streptokinase.
The absorption of penicillin G when taken PO may be decreased if taken with
cholestyramine (Questran) or colestipol (Colestid). Similarly, the use of penicillin
might decrease the effectiveness of estrogen contained in contraceptives.
Two other drugs affected by penicillin are methotrexate (Folex) and probenecid
(Benemid). There is a decrease in the body’s ability to clear methotrexate when
penicillin is present. There can be a build up of methotrexate resulting in toxicity.
Probenecid decreases renal secretion of penicillin resulting in an increase of
the serum level of penicillin.Penicillin, Nursing Diagnosis, and
Collaborative Problems
A patient who is receiving penicillin may experience one or more conditions that
require intervention. Here are the common nursing diagnoses that are related to
a patient who is receiving penicillin.- Altered protection against infection related to reduction in normal flora
(superinfection) - Altered bowel elimination pattern related to antibiotic-associated pseudo-
membranous colitis - Fluid volume deficit related to nausea, vomiting, and/or diarrhea
(^214) CHAPTER 13 Antimicrobials—Fighting Infection