Chapter 17 - Anti-Infective Drugs Flashcards Preview

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Flashcards in Chapter 17 - Anti-Infective Drugs Deck (41)
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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.



(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).



(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)

1. Site of the infection. This helps determine the initial empiric anti-infective regimen.

2. Status of hepatic and/or renal function. Lower doses or alternative drugs might be indicated with impairment.

3. Age of the patient. Some anti-infective are more toxic to children or older patients. Lower doses or alternative drugs might be indicated.

4. 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.

5. 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.

6. 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)

1. 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.

2. 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.

3. 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.



(P. 286 and 595)

Suspensions containing antigenic molecules derived from a microorganism, given to stimulate an immune response to an infectious disease.



(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.



(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).



(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).



(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.



(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.



(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.



(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.



(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.



(P. 296)

Are broad-spectrum antibiotics used in the treatment of infections caused by rickettsia, chlamydia, or some uncommon bacteria.


There are four antifungals:

(P. 297-299)

• Amphotericin B
• Fluconazole
• Micafungin
• Nystatin


Antifungal agents

(P. 297)

Are used to treat specific susceptible fungal diseases. The medications are quite different in action and purpose and are therefore treated separately.


Antifungal agent: Amphotericin B

(P. 297 and 298)

Is administered IV for the treatment of severe systemic, potentially fatal infections caused by susceptible fungi including Candidia.


Antifungal agent: Fluconazole

(P. 298)

Fluconazole (Diflucan) is one of the most widely prescribed antifungal agents. It acts against many fungal pathogens including most Candida without the serious toxicity of Amphotericin B.


Antifungal agent: Micafungin

(P. 299)

Micafungin (Mycamine) belongs to one of the newer classes of antifungals. Given IV, this drug provides new treatment options against Candida and aspergillus species.


Antifungal agent: Nystatin

(P. 299)

Is structurally related to Amphotericin B and is used orally to treat oral cavity Candidiasis.


Antituberculosis agents

(P. 299 - 302)

Are administered for two purposes:

1. to treat latent or Asystematic infection (no evidence of clinical disease), for instance, after exposure to active tuberculosis and or significantly positive PPD (purified protein derivative) skin test.

2. to treat active clinical tuberculosis and prevent relapse.


Tuberculosis (TB)

(P. 299)

Tuberculosis (TB) is caused by a bacterium called mycobacterium tuberculosis, which primarily attacks the lungs.



(P. 303)

Is used in the treatment of serious respiratory tract infections, septicemia, osteomyelitis, serious infections of the female pelvis caused by susceptible bacteria, and for pneumocystis jirovecii pneumonia associated with AIDS.

• it is also used in prophylactic regimen in dental procedures for penicillin allergic patients.

• clindamycin may be viable therapeutic option for community-acquired MRSA.

• Has a wider spectrum of activity than lincomycin, from which it is derived.


Metronidazole (Flagyl)

(P. 304)

Is a synthetic antibacterial and antiviral protozoal agent that is effective against protozoa such as trichomonas vaginalis and for the treatment of amebiasis and giardiasis.



(P. 305)

Is structurally unrelated to other available antibiotics. IV Vancomycin is used in the treatment of potentially life-threatening infections caused by susceptible organisms.

☆ It is the drug of choice for MRSA.



(P. 307)

A class of anti-infective drugs used in combination with other drugs to slow the development of resistance; used in the treatment of urinary tract infections, enteritis and opportunistic infections of AIDS.


Urinary anti-infectives

(P. 309 and 595)

Drugs used for initial or recurrent urinary tract infections caused by susceptible organisms, usually bacteriostatic instead of bactericidal.