Chapter 17 - Anti-Infective Drugs Flashcards
Terminology
Culture and sensitivity (C and S) tests
P. 283
The first step in treatment is identifying the causative organism and the specific medication to which it is sensitive. This test will be ordered ( e.g., wound, throat, urine, or blood), based on symptoms.
- it is imperative to obtain the appropriate specimen before administering medication.
- results of C and S tests will not be available for a 24 to 48 hours.
Empiric
P. 283
In the meantime, while waiting for the C&S test results, a physician may order an anti-infective regimen that would likely be active against the organisms in countered at the given site of infection (e.g., brain, lung, skin).
Resistance
P. 284 and 593
An organisms lack of response to antibiotics when they are used too often or treatment is incomplete.
• when drugs are no longer effective.
Methicillin-resistant Staphylococcus aureus (MRSA)
P. 284
An organism resistant to most antibiotics.
• Vancomycin IV is one of the small number of drugs effective against MRSA.
Effective strategies to combat the problem of resistance to antibiotics:
(P. 284)
- Better patient and physician education on appropriate anti-infective used, accurate diagnosis, and targeted treatment of infections.
- Strict adherence to preventative measures such as routine hand-washing or alcohol wiping between patient visit and Rapid isolation of patients with resistant infections is also extremely important.
Selection of anti-infective drugs is based on several factors:
(P. 285)
- Site of the infection. This helps determine the initial empiric anti-infective regimen.
- Status of hepatic and/or renal function. Lower doses or alternative drugs might be indicated with impairment.
- Age of the patient. Some anti-infective are more toxic to children or older patients. Lower doses or alternative drugs might be indicated.
- Pregnancy or lactation. Some anti-infective can cross the placenta and cause damage to the developing fetus, for example tetracycline or streptomycin. Others can be carried in the breast milk and can cause toxicity to the infant.
- Likelihood of organisms developing resistance. Sometimes a combination of drugs is used to decrease the chance of the organism developing resistance to a single drug. Examples of combination therapy and therapy include sulfamethoxazole and trimethoprim combined to treat UTIs. Another example is the combination of three or more drugs to treat tuberculosis.
- No one allergy to the anti-infective drug. In such cases, an alternative should be used.
Adverse reactions to anti-infective are divided into three categories:
(P. 285)
- Allergic hypersensitivity. This is an over response of the body to a specific substance. A mild reaction would be rash, hives or mild fever. Severe reaction would be anaphylaxis, a sudden onset of dyspnea, chest constriction, shock, and collapse.
- Direct toxicity. Results in tissue damage, such as ototoxicity (hearing difficulties or dizziness), nephrotoxicity (kidney problems), hepatotoxicity (liver damage), blood dyscrasias (abnormalities in blood components), phlebitis, or phototoxicity.
- Indirect toxicity, or superinfection. manifested as a new infection as a result of killing the normal flora in the intestines or mucous membranes, especially with broad-spectrum antibiotics and therefore allowing colonization of these areas with different resistant bacteria or fungi.
Vaccines
P. 286 and 595
Suspensions containing antigenic molecules derived from a microorganism, given to stimulate an immune response to an infectious disease.
Antibiotics
P. 286
Refers to a large spectrum of medicines that are useful for treating and preventing infections caused by bacteria.
• These types of medications have no effect on viral, fungal, or other types of infections.
☆ Their improper use or used without proper indication can lead to resistance.
Aminoglycosides
P. 288 and 583
Drugs used in combination with other antibiotics that treat many infections caused by gram-negative and gram-positive bacteria.
• usually administered parenterally (i.e., IM or IV).
Aminoglycosides
P. 288 and 583
Drugs used in combination with other antibiotics that treat many infections caused by gram-negative and gram-positive bacteria.
• usually administered parenterally (i.e., IM or IV).
Cephalosporins
P. 289
Are semi-synthetic beta-lactam antibiotic derivatives produced by a fungus.
☆ they are related to penicillin, and some patients allergic to penicillin are also allergic to cephalosporins.
• cephalosporins are classified as first, second, third, fourth, or fifth generation, according to the organism susceptible to their activity.
Macrolides
P. 290
Such as erythromycin, clarithromycin, and azithromycin, are used for the treatment of many infections of the respiratory tract, for skin conditions such as acne, or for some STIs when the patient is allergic to penicillin.
• Macrolides are considered among the least toxic antibiotics.
Penicillins
P. 292
Are beta-lactam antibiotics produced from certain species of a fungus.
- they are used to treat many streptococcal and some staphylococcal and meningococcal infections, including respiratory and intestinal infections.
- penicillin is the drug of choice for the treatment of syphilis and is also used prophylactically to prevent reoccurrences of rheumatic fever.
Carbapenems
P. 293
Such as meropenem (Merrem) belonging to the beta-lactam class of antibiotics and have a very broad spectrum of activity against gram-negative and gram-positive organisms, including anaerobes and many multidrug-resistant pathogens.
• they are primarily used to treat pneumonia, febrile neutropenia, intra-abdominal infections, diabetic foot infections, and significant polymicrobial infections.
Quinolones
P. 293
Such as ciprofloxacin (Cipro), levofloxacin (Levaquin) or moxifloxacin (Avelox) are used in adults for the treatment of some infections of the urinary tract, sinuses, lower respiratory tract, GI tract, skin, bones, and joints, and gonorrhea.
☆ these agents should be reserved for infections that require therapy with a fluoroquinolone such as pseudomonas infections or when a person is allergic to other antibiotics.
