Anti-infective Pharmacology

Question 1

What are antibiotics derived from?

Answer 1

Derived from microorganisms
Ex. Penicillin, cephalosporins
- All antibiotics are antibacterial, not all antibacterials are antibiotics

Question 2

How are antibacterial agents made?

Answer 2

Synthetic- made in a lab
Ex. Sulfonamides
- All antibiotics are antibacterial, not all antibacterials are antibiotics

Question 3

What does bactericidal mean?

Answer 3

• Have ability to kill bacteria
• Irriversible process

Question 4

What does bacteriostatic mean?

Answer 4

• Have the ability to inhibit or retard the growth of bacteria
• Reversible process (able to grow and multiply again)

Question 5

What does spectrum mean?

Answer 5

Range of anti-infective properties
- May be narrow (few organisms)
- May be wide or broad (many organisms)

Question 6

What is resistance?

Answer 6

• Ability of an organism to be unaffected by an anti-infective agent
• May be natural or acquired

Question 7

What is suprainfection (superinfection)?

Answer 7

• Appearance of a new infection w/ other than the original organism while the pt. is taking an antimicrobial agent
• Above and beyond the initial infection
• Ex. Candidiasis as a result of taking tetracycline

Question 8

What is synergism?

Answer 8

Effect of two agents used together is greater

Question 9

What is antagonism?

Answer 9

Effect of two agents together is lesser or negated

Question 10

What is the etiology of dental infection in the early stages?

Answer 10

Gram-positive aerobes

Question 11

What is the etiology of dental infection in the middle and later stages?

Answer 11

Gram-positive and gram-negative anaerobic organisms increase until they coalesce into an abscess

Question 12

What are first-line treatments?

Answer 12

Penicillin VK
Amoxicillin

Question 13

What is an alternative agent to Penicillin and amoxicillin? What also needs to be taken?

Answer 13

• Alternative agent: clindamycin
• Adjunctive agent: metronidazole
• The alternative agent does not always cover all gram (-) anaerobes so we add an adjunctive agent

Question 14

What is a second-line treatment? Why would we want to avoid this?

Answer 14

• Azithromycin (Z-Pack)
• Can cause drug interactions and arrhythmias

Question 15

What drug interaction can happen when an antibacterial agent is used in a pt. taking Coumadin (warfarin)?

Answer 15

• Antibiotics reduce gastrointestinal flora that make vitamin K which means no clotting factors
• Increases the effects of warfarin (bleeding)

Question 16

Why should bacteriostatic and bactericidal antibiotics not be used togther?

Answer 16

They will miss the anaerobes because they have slowed down

Question 17

What interaction can occur between antibacterial agents and oral contraceptives?

Answer 17

Reduced effectiveness

Question 18

What is the mechanism of action of penicillin?

Answer 18

Bactericidal: inhibits cell wall synthesis

Question 19

What are the types of Penicilins?

Answer 19

• Narrow- penicillin VK
• Broad- amoxicillin
• Penicillinase-resistant- methicillin and amoxicillin+clavulanate (Augmentin)- used to treat MRSA

Question 20

What are the uses and adverse effects of penicillins?

Answer 20

Uses: Treatment of abscesses and endocarditis prophylaxis
Adverse effects: Rash, GI distress

Question 21

What is the mechanism of action of clindamycin (Cleocin)?

Answer 21

Dose dependent: Bactericidal (large dose) or bacteriostatic (small dose)
- Inhibits bacterial protein synthesis
- Retards bacterial growth and reproduction

Question 22

When would clindamycin be used?

Answer 22

If a patient has a penicillin allergy

Question 23

Patient care considerations for clindamycin (Cleocin)

Answer 23

High risk of pseudomembranous colitis
- Severe, persistant diarrhea
- Do not use anti-diarrheals
- Discontinue drug

Question 24

Mechanism of action of Metronidazole (Flagyl)

Answer 24

Bactericidal (will kill C. dif)
- Causes bacterial DNA to lose structure

(End in -azole, but not an anti-fungal)

Question 25

Uses for metronidazole

Answer 25

• Tx of gram-negative infections
• Tx of protozoal infections
• Tx of trichomonal infections
• Tx of amoebic infections

Question 26

Adverse effects and patient care considerations for metronidazole

Answer 26

• Adverse effects: GI distress and black hairy tongue
• Pt. care: Metallic taste and rxns with alcohol and alcohol products (intense nausea/vomitting)

Question 27

Mechanism of action of macrolides

Answer 27

Bactericidal or bacteriostatic (dose dependent)
- Inhibits bacterial protein synthesis

Question 28

Types of macrolides and what are they used to treat?

Answer 28

• erythromycin (no longer used)
• clarithromycin (Biaxin)
• azithromycin (Zithromax/Z-pack)
• Used to treat lymes disease

Question 29

What are macrolides used for?

Answer 29

Tx of upper respiratpry infections and otitis media

Question 30

Mechanism of action of tetracyclines

Answer 30

Bacteriostatic
- Inhibit bacterial protein synthesis
- Not used in dentistry systemically

Question 31

Types of tetracyclines

Answer 31

• doxycycline (Vibramycin)
• minocycline (Minocin)

Question 32

What are tetracyclines used to treat?

Answer 32

• Acne, dermatologic conditions
• Periodontitis

Question 33

Adverse effects of tetracyclines

Answer 33

• GI distress
• Xerostomia, gossitis, stomatitis
• Photosensitivity (burning/freckling)
• Drug interactions (calcium, iron, aluminum, magnesium)
• Permanent tooth discoloration

Question 34

Tetracyclines used in dentistry

Answer 34

• Atridox (doxycycline hyclate gel)- used topically in the pocket
• Arestin (minocycline microspheres)
• Periostat (doxycycline hyclate capsules)- reduces elevated collagenase activity in GCF ** only one used systemically **

Question 35

Mechanism of action of cephalosporins

Answer 35

Bactericidal- inhiibit bacterial wall sysnthesis

Question 36

What are the types of cephalosporins, how are they organized?

Answer 36

Organized into “generations” based on width of spectrum
Narrow to broad
- 1st- cephalexin (Keflex), cefadroxil (Duricef)
- 2nd- cefcalor (Ceclor), cefuroxime (Ceftin)
- 3rd- cefdinir (Omnicef), cefpodoxime (Vantin)
- 4th cefepime (Maxipime)