Compare azithromycin vs. penicillin

Head-to-head comparisons of medication uses, side effects, ratings, and more.

Zithromax (azithromycin)

Prescription only
Treats bacterial infections.

Zithromax (azithromycin) is good for treating many bacterial infections and is available in generic form. However, it may cause headache, dizziness, or rash.

4.0/ 5 average rating with 909 reviewsforazithromycin
Treats bacterial infections.

Penicillin VK (penicillin) is good at treating strep throat and is cheap, however, it can only be used for certain infections as many bacteria have developed resistance to it.

3.9/ 5 average rating with 1297 reviewsforpenicillin
  • Available as a generic in the tablet and suspension form.
  • The suspension can be used if you have problems swallowing.
  • Used to treat many types of bacterial infections.
  • Bacteria is less resistant to this antibiotic, meaning that Zithromax (azithromycin) will fight off the bacteria better. Your doctor may run tests to see which antibiotics will kill the bacteria causing your infection.
  • Immediate release form can be taken with or without food.
  • Compared to alternatives, Penicillin VK (penicillin) is the preferred choice for treating strep throat infections.
  • This medicine is available as a generic, which is cheap.
  • It’s also available in different forms: pill and liquid.
  • Must space out antacids by at least 2 hours.
  • Use with caution if you have liver disease.
  • Must be used with caution if you are on medications to thin the blood (anticoagulants) because of increased risk of bleeding.
  • Many bacteria are resistant to Penicillin VK (penicillin), so it only works for certain infection typically in ear, nose, and throat.
  • Penicillin VK (penicillin) has a bitter taste. Children might not like the taste.
Used for
Dosage forms
  • Pill
  • Liquid
  • Extended-release liquid
  • Pill
  • Liquid
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909 reviews so far
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Have you used Zithromax (azithromycin)?

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1297 reviews so far
saidit'sworth it
saiditworked well
saidit'sa big hassle

Have you used Penicillin VK (penicillin)?

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Side effects
3possible side effects
  • Vomiting
  • Diarrhea
  • Abdominal pain
See more detailed side effects
The Penicillin VK (penicillin) FDA package insert doesn’t have numbers about how common side effects are.
Risks and risk factors
  • Diarrhea caused by bacteria (Clostridium difficile)
  • Liver damage
    • History of liver disease
  • Myasthenia gravis
    • Myasthenia gravis
  • Serious allergic reaction
  • Abnormal heartbeat
    • QT prolongation
    • Arrhythmia
    • Drugs that cause prolonged QT interval
    • Abnormal electrolytes
    • Elderly
See more detailed risks and warnings
  • Diarrhea
    • Taking Penicillin VK (penicillin) for a long time
  • Interaction with birth control pills
  • Allergic reaction
    • History of severe allergic reaction to Penicillin VK (penicillin)
    • Cephalosporin medication allergy
See more detailed risks and warnings