CPJE Secrets 2026: Miscellaneous Notes

Which antibiotic is the only one that has been clinically proven to decrease the effectiveness of birth control pills?

Rifampin

What are first-line choices to treat P. aeruginosa?

Beta-lactams: penicillins, cephalosporins, and carbapenems (NOT imipenem)

Macrolides: azithromycin, erythromycin (NOT clarithromycin)

Other: clindamycin, metronidazole for bacterial vaginosis/vaginal trichomoniasis

What should be on the label for ALL oral suspensions?

“Shake, take until gone, and refrigerate after mixed.”

Which antibiotics should NOT be refrigerated?

Azithromycin

Clarithromycin

Clindamycin

Fluoroquinolones

Voriconazole

“As Clear as Loma Linda to Fountain Valley.”

Which antibiotics can cause a rash (non-serious)?

All beta lactams (and most other antibiotics)

C. diff Infection (CDI) Treatment

Firvanq (vancomycin PO) 125mg QID

• Add Flagyl (metronidazole) IV for severe/complicated CDI

AND/OR

Dificid (fidaxomicin) 200mg PO BID for 10 days

Other Treatment

Zinplava (bezlotoxumab) 10mg/kg IV for recurrent CDI in adults already receiving antibacterials. This is NOT an antibacterial in itself!

Important Pediatric Doses of Antibiotics

Amoxil, Moxatag (amoxicillin)

50 mg/kg to a max of 2g or 40mL

Suspension usually comes in 250mg/5mL → 50mg/mL.

Given this math: 1 mL/kg of child weight.

For children with penicillin allergies:

Cleocin (clindamycin) 20mg/kg max 600mg

Zithromax (azithromycin) 15mg/kg max 500mg

Biaxin (clarithromycin) 15mg/kg max 500mg

Treatment of Travelers’ Diarrhea

Zithromax (azithromycin) 1000mg PO once OR 500mg PO QD for 3 days

Cipro (ciprofloxacin) 750mg PO once OR 500mg PO BID for 3 days

Levaquin (levofloxacin) 500mg PO QD for 1-3 days

Ofloxacin 400mg PO BID for 1-3 days

Rifamycin SV 388mg PO BID for 3 days

Xifaxan (rifaximin) 200mg PO TID for 3 days

Can combine with Imodium (loperamide) 4mg initial dose followed by 2mg after each loose stool max 16mg in 24 hours

Rifaximin Indiciations

Xifaxan (rifaximin) is an antibacterial that has different dosing based on what it is used for. Be aware of the differences!

IBS w/diarrhea: 550mg PO TID for 14 days

Hepatic Encephalitis Prevention: 550mg PO BID

Travelers’ Diarrhea: 200mg PO TID for 3 days