Antibiotics

Question 1

Tetracyclines: Type, Names (3), category

Answer 1

Doxycycline
Minocycline (not commonly used)
Tetracycline
*Names w/ -cycline
Category D
Bacteriostatic

Question 2

Tetracyclines: Contraindications

Answer 2

Avoid in pregnancy, infancy, or children < 9 y.o.

They may cause permanent discoloration of teeth (brown/yellow) and skeletal defects if taken by the aforementioned Pts

Question 3

Tetracyclines: Adverse Rxns

Answer 3

Photosensitivity (severe sunburns w/ minimal sunlight): use sunscreen, wide-brim hats, sunglasses
Esophageal ulcerations (rare): take tablet w/ a full glass of H2O

Question 4

Doxycycline: Usage

Answer 4

Acne, rosacea
Chronic UTI
STDs (GC, chlamydia)
Lyme Dz
Rocky Mt. spotted fever
Anthrax

Question 5

Tetracycline: Usage

Answer 5

Moderate acne, rosacea (1st line)

AECB (chronic bronchitis, acute exacerbation)

Question 6

Macrolides: Type, Names (3), category

Answer 6

Erythromycin
Azithromycin (Z-pack)
Clarithromycin (Biaxin)
Category B except for clarithromycin (Cat. C)
Bacteriostatics that cover gram-pos cocci. Known for more drug interactions than some other Abx

Question 7

Macrolides: Drug interactions, contraindication

Answer 7

Many major drug interactions mediated by inhibition of hepatic cytochrome CYP (P450) 3A enzymes.
Contraindication: Myathenia gravis (resp. failure)

Question 8

Macrolides: Drug interaction w/ warfarin (Coumadin)

Answer 8

Warfarin (Coumadin), avoid taking w/ antacid (less effective)

Question 9

Macrolides: Drug interaction w/ verapamil, amlodipine, diltiazem, amiodarone

Answer 9

With verapamil (Calan), amlodipine (Norvasc), diltiazem (Cardizem), amiodarone, etc.: QT prolongation/bradyarrhythmias

Question 10

Erythromycin: Common side effects

Answer 10

N/V, abdomin pain, diarrhea. Rx azithromycin (Z-pack) or clarithromycin (Biaxin) instead

Question 11

A good alternative antibiotic for these patients with gram-positive bacterial infections

Answer 11

• Macrolides such as azithromycin x 5 days (Z-Pack) or clarithromycin (Biaxin) PO BID
• Clindamycin (Cleocin): slightly higher risk of C. diff
• Quinolones with gram-positive activity (levofloxacin, gatifloxacin) are an option for some infections

Question 12

Good Abx if a patient has both mono and strep throat

Answer 12

• penicillin (if not allergic) or a macrolide
  Note: Do not Rx Amoxicillin. About 70% to 90% of patients with mono taking amoxicillin may break out with a “nonallergic” generalized maculopapular rash (mechanism is not well understood).

Question 13

Which Abx to avoid if a Pt is allergic to penicillin?

Answer 13

Cephalosporin

Question 14

What should you consider if a Pt has atypical pneumonia and was on a macrolide in the previous 3 months?

Answer 14

Consider macrolide-resistant S. pneumoniae