Learning Objectives
Upon completion of this chapter, you will be able to:
• Describe three common adverse reactions associated with the use of anti-infectives.
• Describe therapeutic actions, indications, pharmacokinetics, contraindications, and most common adverse reactions, and important d...
WEEK 4 – Chemotherapeutic Agents ➢ The cost of the drug as well as its potential
adverse effects and the possibility of patient
Learning Objectives
allergies must be considered.
Upon completion of this chapter, you will be able to:
PREVENTING PATHOGEN RESISTNACE
• Describe three common adverse reactions
- The usefulness of anti-infective drugs is limited
associated with the use of anti-infectives.
by the pathogens that may develop resistance
• Describe therapeutic actions, indications, to a drug’s action.
pharmacokinetics, contraindications, and most
common adverse reactions, and important RESISTANCE
drug-drug interactions associated with each of
- is the ability of a microorganism to live and
the classes of antibiotics.
grow in the presence of an anti-infective drug.
• Outline nursing considerations for patients
- Usually results from genetic mutation of the
receiving each class of antibiotic.
microorganism.
ANTI-INFECTIVE AGENTS
THE RISE OF THE RESISTANCE MOVEMENT
Drug List
➢ Indiscriminate use of anti-infective drugs has
• Bacitracin serious consequences.
• Chloramphenicol ➢ Unnecessary exposure of organisms to these
• Meropenem drugs encourages the emergence of resistant
• Polymyxin B strains.
• Vancomycin ➢ These resistant strains are likely to do far more
damage than their predecessors.
DRUGS AND INFECTION
Anti-infective drugs should be reserved for patients
When infection attacks the body, anti-infective drugs with infections caused by susceptible organisms and
can help turn the tide of battle. should be used in high enough doses and for an
appropriate period.
Four types of anti-infective drug exist:
New anti- infective drugs should be reserved for
• Antibacterial
severely ill patients with serious infections that don’t
• Antiviral
respond to conventional drugs.
• Antitubercular
• Antifungal ANTIBIOTICS
Selecting an appropriate anti-infective drug to treat a Antibacterial Drugs
specific infection involves several important factors:
➢ also known as antibiotics, are drugs that either
➢ The microorganisms must be isolated and kill bacteria or inhibit the growth of bacteria.
identified-generally through growing a culture. ➢ They’re mainly used to treat systemic (involving
➢ Its susceptibility to various to drugs must be the whole body rather than a localized area)
determined. bacterial infections.
(culture and sensitivity results take 48 hours, treatment AMINOGLYCOSIDES
typically starts at assessment and is then reevaluated
- Are bactericidal (they destroy bacteria)
when test results are obtained.)
amikacin
➢ location of the infection must be considered.
gentamicin
(for therapy to be effective, an adequate concentration kanamycin
of the anti-infective drug must be delivered to the neomycin
infection site.) streptomycin
tobramycin
1
,ARENAS, ERALY (BSN-2D) PHARMACOLOGIC NURSING
AMINOGLYCOSIDES THEY’RE EFFECTIVE AGAINST: ➢ The peak level is the highest concentration of a
drug in the patient's bloodstream.
• Gram-negative bacilli
➢ A trough level is drawn immediately before the
• Some aerobic gram-positive bacteria next dose of the drug is administered. A peak
• Mycobacteria level is drawn 1 to several hours after the drug
• Some protozoa is administered (depending on the drug).
PHARMACOKINETICS
(How the drugs circulate)
➢ Because aminoglycosides are absorbed poorly
from the GI tract, they’re usually given
parenterally except neomycin, which is given
orally for preoperative bowel cleansing.
➢ After IV or IM administration, aminoglycoside BACTERIAL RESISTANCE TO AMINOGLYCOSIDES MAY
absorption is rapid and complete. BE RELATED TO:
➢ Aminoglycosides aren’t metabolized. They’re
➢ failure of the drug to cross the cell membrane
excreted primarily by the kidneys.
➢ altered binding to ribosomes
PHARMACODYNAMICS ➢ destruction of the drug by bacterial enzymes.
(How drugs act)
Penetration power provided by penicillin
➢ Aminoglycosides act as bactericidal drugs
➢ Some gram-positive enterococci resist
against susceptible organisms by binding to the
aminoglycoside transport across the cell
bacteria’s 30S subunit, a specific ribosome in
membrane.
the microorganism, thereby interrupting
➢ When penicillin is used with aminoglycoside
protein synthesis and causing the bacteria to
therapy, the cell wall is altered, allowing the
die.
aminoglycoside to penetrate the bacterial cell.
➢ In combination therapy, penicillin should be
given first.
PHARMACOTHERAPEUTICS
(How drugs are used)
Aminoglycosides are most useful in treating:
➢ infections caused by gram-negative bacilli
➢ serious nosocomial (hospital-acquired)
infections, such as gram-negative bacteremia
(abnormal presence of microorganisms in the
bloodstream), peritonitis (inflammation of the
NURSING CONSIDERATIONS peritoneum, the membrane that lines the
➢ Monitor the patient for adverse effects, such as abdominal cavity), and pneumonia in critically ill
ototoxicity, nephrotoxicity, anaphylaxis, patients
thrombocytopenia, and agranulocytosis. ➢ urinary tract infections (UTIs) caused by enteric
➢ Peak gentamicin levels occur 1 hour after IM bacilli that are resistant to less toxic
injection and 30 minutes after IV infusion; antibacterial drugs, such as penicillins and
check trough levels before the next dose. cephalosporins
➢ The trough level is the lowest concentration in ➢ infections of the central nervous system (CNS)
the patient's bloodstream; therefore, the and the eye (treated with local instillation).
specimen should be collected just prior to
administration of the drug.
2
,ARENAS, ERALY (BSN-2D) PHARMACOLOGIC NURSING
Aminoglycosides are used in combination with ➢ Assess for drug interactions and adverse
penicillins to treat infections caused by gram-positive reactions.
organisms, such as staphylococci and enterococci. ➢ Assess the patient’s and family’s knowledge of
drug therapy.
Combination therapy increases the drugs’
effectiveness. KEY NURSING DIAGNOSES
INDIVIDUAL AMINOGLYCOSIDES MAY HAVE THEIR • Risk for injury related to adverse effects of drug
OWN PARTICULAR USEFULNESS: • Risk for infection related to drug-induced
superinfection
➢ Streptomycin is active against many strains of
• Risk for deficient fluid volume related to
mycobacteria, including Mycobacterium
adverse GI reactions
tuberculosis, and against the grampositive
bacteria Nocardia and Erysipelothrix. PLANNING OUTCOME GOALS
➢ Amikacin, gentamicin, and tobramycin are
• The patient’s risk of injury will be minimized.
active against Acinetobacter, Citrobacter,
• The patient’s risk of superinfection will be
Enterobacter, Escherichia coli, Klebsiella,
minimized.
Proteus (indole-positive and indole-negative),
• The patient’s fluid volume will remain within
Providencia, Pseudomonas aeruginosa, and
normal limits as evidenced by vital signs and
Serratia.
intake and output.
➢ Neomycin is given orally to suppress intestinal
bacteria before surgery and is active against E. IMPLEMENTATION
coli infectious diarrhea.
• Keep the patient well hydrated to minimize
ADVERSE REACTIONS chemical irritation of the renal tubules.
• Don’t add or mix other drugs with IV infusions,
• Neuromuscular reactions, ranging from
particularly penicillins, which inactivate
peripheral nerve toxicity to neuromuscular
aminoglycosides. If other drugs must be given
blockade
IV, temporarily stop infusion of the primary
• Ototoxicity
drug.
• Renal toxicity
• Follow the manufacturer’s instructions for
ADVERSE REACTIONS TO ORAL AMINOGLYCOSIDES reconstitution, dilution, and storage of drugs;
INCLUDE: check expiration dates.
• Shake oral suspensions well before
• Nausea
administering them.
• Vomiting
• Diarrhea EVALUATION
NURSING PROCESS ASSESSMENT • Patient maintains pretreatment renal function
and hearing levels.
➢ Obtain the patient’s allergy history.
• Patient is free from infection.
➢ Obtain culture and sensitivity tests before
• Patient maintains adequate hydration.
giving the first dose; therapy may begin pending
test results. Check these tests periodically to PENICILLINS
assess the drug’s efficacy.
- remain one of the most important and useful
➢ Assess vital signs, electrolyte levels, hearing
antibacterial drugs, despite the availability of
ability, and renal function studies before and
numerous others.
during therapy.
- The penicillins can be divided into four groups.
➢ Weigh the patient and review baseline renal
function studies before therapy and then
regularly during therapy. Notify the prescriber
of changes so that the dosage may be adjusted.
3
, ARENAS, ERALY (BSN-2D) PHARMACOLOGIC NURSING
PENICILLINS AND PENICILLINASE-RESISTANCE although specific penicillins are more effective
ANTIBIOTICS against specific organisms.
Penicillins (natural penicillins) ADVERSE REACTIONS
penicillin G benzathine
Hypersensitivity reactions are the major adverse
penicillin G potassium
reactions to penicillins,
penicillin G procaine
including:
penicillin V
• anaphylactic reactions
Extended-Spectrum Penicillins
• serum sickness (a hypersensitivity reaction
amoxicillin
occurring 1 to 2 weeks after injection of a
Ampicillin
foreign serum)
Penicillinase-Resistant Antibiotics • drug fever
• various skin rashes.
nafcillin
oxacillin Adverse GI reactions associated with oral penicillins
include:
PHARMACOKINETICS
(How drugs circulate) • tongue inflammation
• nausea and vomiting
- After oral administration, penicillins are
• diarrhea.
absorbed mainly in the duodenum and the
upper jejunum of the small intestine. CNS reactions may include:
PHARMACODYNAMICS • lethargy
(How drugs act) • hallucinations
• anxiety or depression
➢ Penicillins are usually bactericidal in action.
• confusion
They bind reversibly to several enzymes outside
• seizures.
the bacterial cytoplasmic membrane.
➢ These enzymes, known as penicillin-binding NURSING PROCESS ASSESSMENT
proteins (PBPs), are involved in cell wall
• Obtain a history of the patient’s infection
synthesis and cell division. Interference with
before therapy; reassess for improvement
these processes inhibits cell-wall synthesis,
regularly thereafter.
causing rapid destruction of the cell.
• Assess the patient’s allergy history. Try to find
out whether previous reactions were true
hypersensitivity reactions or adverse reactions
(such as GI distress) that the patient interpreted
as an allergy.
• Obtain culture and sensitivity tests before giving
the first dose; therapy may begin pending test
results. Repeat these tests periodically to assess
the drug’s effectiveness.
ASSESSMENT
PHARMACOTHERAPEUTICS
• Monitor vital signs, electrolytes, and renal
➢ No other class of antibacterial drugs provides as function studies.
wide a spectrum of antimicrobial activity as the • Assess the patient’s consciousness and
penicillins. As a class, they cover gram-positive, neurologic status when giving high doses; CNS
gram-negative, and anaerobic organisms, toxicity can occur.
4
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