Antibiotics, Antifungals & Antivirals Flashcards Preview

Pharmacy Technician > Antibiotics, Antifungals & Antivirals > Flashcards

Flashcards in Antibiotics, Antifungals & Antivirals Deck (39)
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1
Q

antibiotics

A

a class of drugs that inhibit the growth of bacteria without harming the human host

2
Q

selective toxicity

A

important feature of antibiotics that enable them to target and kill bacteria without harming the infected host

3
Q

Alexander Fleming

A

1929 discovered PCN

4
Q

Gram-positive bacteria

A

those bacteria that create a positive result in the Gram stain test for bacteria

5
Q

Gram-negative bacteria

A

bacteria that give a negative result on the Gram stain for bacteria

6
Q

Bactericidal

A
  • cidal = “to kill or have killing power”
  • bactericidal antibiotics typically kill the bacteria it targets
7
Q

Bacteriostatic

A
  • static = stopping or controlling
  • bacteriostatic antibiotics stop bacteria growth and replication. The host’s immune system must complete the task of clearing the body of the invading bacterial species
8
Q

Antibiotic Mechanisms of Action

A
  1. inhibit cell wall synthesis
  2. inhibit protein synthesis
  3. interfere with essential bacterial enzymes
9
Q

Antibiotic Classes

A
  • ß-lactam
  • Other cell-wall synthesis inhibitors (cell wall inhibitors that lack the beta-lactam ring)
  • Protein-synthesis inhibitors
  • Quinolone
10
Q

ß-lactam

A

works by inhibiting bacterial cell-wall synthesis by use of the beta-lactam ring molecular structure that interferes with the bacteria enzymes used to build its cell walls; ultimately killing the bacteria.

This class of antibiotics includes:

  • PCN
  • cephalosporins
  • carbapenems
  • monobactams
11
Q

ß-lactamase

A

enzymes bacteria have developed to become resistant to beta-lactam antibiotics. the lactamase reacts with the beta-lactam ring in the antibiotic, deactivating it = deactivating the antibitoic.

12
Q

Penicillinase

A

the specific beta-lactamase that dectivates PCN

13
Q

ß-lactamase inhibitor

A

one way around the inactivation of antibiotics is to give a beta-lactamase inhibitor such as:

  • clavulanic acid
  • sulbactam

which increase the effectiveness of the antibiotic

14
Q

Penicillins

A
  • group of antibiotics derived from Penicillium fungi
  • bactericidal
  • natural PCN’s are made from the fungi or mold
  • chemically modified PCN’s developed to improve resistance to beta-lactamases
  • -cillin
15
Q

paresthesia

A

numbness and tingling

16
Q

unicaria

A

hives

17
Q

PCN Allergic Reactions

A
  • itching
  • paresthesia
  • wheezing
  • choking
  • fever
  • swelling
  • generalized uticaria
18
Q

cephalosporins

A
  • beta-lactams derived from cephalosporium fungi
  • ceph- or cef-
  • classified by their generation (1st, 2nd, 3rd, etc.)
19
Q

carbapenems

A
  • -enem
  • broad spectrum beta-lactam
  • highly resistant to most beta-lactamases
  • not very soluble an have poor oral bioavailability
  • delivered via IV in hospital setting
  • used for serious infections as an antibiotic of last resort
20
Q

Poor Oral Bioavailability

A

given in oral dosage, the medication is difficult to absorb into the body and become effective

21
Q

monobactams

A
  • aztreonam is the only currently available drug in this class
  • works against gram-negative bacteria
  • highly resistant to beta-lactamases
22
Q

Other Antibiotic Cell-Wall Synthesis Inhibitors

(those lacking the ß-lactam ring)

A
  • vancymycin
  • bacitracin
  • fosfomycin
  • daptomycin

these medications work similar to the beta-lactam antibiotics, however these medications lack the ß-lactam ring.

additionaly, eacy one of these drugs is different in structure and mechanism of action against the bacterial cell wall

23
Q

protein-synthesis inhibitors

A

works by preventing protein synthesis in bacteria with selective toxicity

  • three main categories
  1. aminoglycosides
  2. tetracyclines
  3. macrolides
24
Q

aminoglycosides

A
  • -mycin
  • broad-spectrum antibiotics
  • poorly absorbed from GI tract
  • administered by IV or other parenteral means
  • Important to note:
    • ototoxic
    • nephrotoxic
    • neuromuscular toxic
  • small safety margin between toxic concentration and therapeutic effect
25
Q

tetracyclines

A
  • -cycline
  • broad-spectrum antibiotics used for both gram-positive and gram-negative bacteria
  • can be given orally – without food – food impares absorption (exceptions are doxycycline and minocycline)
  • major side effects:
    • insoluble chelates - kind of calcium bond that discolors the teeth and inhibits bone growth
  • should not be used with children or pregnant women
26
Q

macrolides

A
  • some end with -mycin
  • most end with -thromycin
  • can be given orally with relatively few side effects
  • useful in treating:
    • mycoplasma infections
    • pneumonia
    • Legionnaires disease
    • diptheria
    • pertussis
27
Q

quinolones

A
  • relatively new class of antibiotics
  • work by inhibiting DNA synthesis
  • -oxacin
  • primarily used to treat UTIs
  • broad spectrum
  • used orally
28
Q

antifungals

A

used to treat fungal infetions; either superficial infections that effect the outer layers of skin, nails and hair -or- systemic fungal infections

  • fungal infections replicate more slowly making treatment problematic
  • these drugs are poorly soluble - making distribution to the site of infection problematic
  • as a result, antifungals typically work to assist the host’s immune system in fighting against the infection
  • must have selective toxicity to be effective
29
Q

Antifungal Classes

A
  • polyene antifungals
  • azole antifungals
  • echinocandins
30
Q

polyene antifungals

A
  • polyene refers to the chemical structure that maks up this class
  • most popular is
    • amphotericin B
  • works by binding to sterols in the fungal cell membrane which disrupts membrane function causing leakage of electrolytes from the cell leading to cell death for the fungus
  • nephrotoxic
  • must be given by IV or topically
31
Q

azole antifungals

A
  • azole = chemical structure of the class
  • work by inhibiting an enzyme fungi use to make sterol, leading to cell death
    • ergosterol
32
Q

echinocandins

A
  • used to treat candida and aspergillus
  • inhibits fungi cell-wall production by targeting glucan
  • given by injection
33
Q

terbinafine

A
  • an antifungal given for superficial infections
  • targets poorly vascularized tissues such as hair, skin and nails
  • administered topically
34
Q

Antivirals

A
  • treat viral infections through the selective targeting of the viral-development cycle
  • vaccination is traditional method
    • a preventative strategy
  • selective toxicity
35
Q

antiviral chemotherapeutics

A
  • developed as an additional fight against viral infections
  • successful in treating HIV, herpes, hepatitis B & C, and influenza A & B
36
Q

Anti-HIV

A
  • drugs in this category work by a variety of mechanisms
  • multiple drugs, targeting different mechanisms, are given as a “cocktail”
  • targets an enzyme called reverse transcriptase
  • “cocktail” drugs are called RTIs - reverse transcriptase inhibitors
  • anti-HIV cocktails usually include one NNRTI and 2 NRTIs used in combinations
  • -ine
37
Q

RTI

A
  • reverse transcriptase inhibitors
  • further divided into:
    • NRTIs - nucleotide reverse transcriptase inhibitors
    • NNRTIs - non-nucleotide reverse transcriptase inhibitors
  • -ine
38
Q

PI

A
  • protease inhibitors
  • also anti-HIV
  • work by interfering with the processing of viral proteins, preventing the formation of new viral particles
  • -vir
  • used in combination:
    • 2 PIs + 2 NRTIs
39
Q

Influenza Drugs

A
  • vaccination is standard approach
  • some antivirals have been developed that work as an alternative to vaccination
  • work by targeting the development cycle of of the flu virus and stopping its replication
    • oseltamivir (Tamiflu)
      • used for influenza A, administered within 48 hours of infection, shortens the duration of symptoms by 1/2