Compare Azithromycin vs. Penicillin

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

Zithromax
(Azithromycin)

Penicillin Vk
(Penicillin)

Kills bacteria. Zithromax (Azithromycin) is good for treating many bacterial infections. It is also available as generic. Talk to your doctor if you've ever had liver disease, myasthenia gravis, or on medications to thin the blood, as the doctor may write an alternative.Kills bacteria. Penicillin Vk (Penicillin) is good for treating many bacterial infections and is available as a generic. You may need to use another form of birth control along with your birth control pills. It's also best taken on an empty stomach but it can cause an upset stomach.
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Reviews & ratings
Button Group. All currently active
Button Group. All currently active
5.443093922651934Azithromycin
Reviews for Zithromax (Azithromycin)
74%
of people say Zithromax (Azithromycin) is worth it
59%
say it works well
11%
say it's a big hassle
Reviews for Penicillin Vk (Penicillin)
71%
3% vs. Zithromax (Azithromycin)
52%
7% vs. Zithromax (Azithromycin)
12%
1% vs. Zithromax (Azithromycin)
Side effects
AzithromycinPenicillin

The Azithromycin FDA package insert doesn’t have numbers about how common side effects are.

More about Azithromycin side effects »

The Penicillin FDA package insert doesn’t have numbers about how common side effects are.

More about Penicillin side effects »
How it works
AzithromycinPenicillin
Zithromax (Azithromycin) is an antibiotic. It kills bacteria by preventing them from reproducing and repairing themselves.Penicillin Vk (Penicillin) is an antibiotic. It kills bacteria by preventing them from making their own protective covering.
Type of medication
AzithromycinPenicillin
Antibiotic
Macrolide
Prescription only
Antibiotic
Penicillin
Prescription only
Available as
AzithromycinPenicillin
  • Pill
  • Liquid
  • Eye drops
  • Pill
Used for (click to learn more)
AzithromycinPenicillin
Risk factors for serious side effects
AzithromycinPenicillin
      • History of liver disease
      • History of myasthenia gravis
      Detailed Zithromax (Azithromycin) risks & warnings »
          • Prior severe allergic reaction to Penicillin Vk (Penicillin)
          Detailed Penicillin Vk (Penicillin) risks & warnings »
          Pregnancy category
          AzithromycinPenicillin
          BFDA pregnancy category (Probably safe)

          Research studies with animals haven’t found a risk to unborn babies, but it hasn’t been properly studied in humans.

          See the FDA package insert
          NFDA pregnancy category (Unknown)

          The FDA hasn’t classified this medicine’s effects on unborn babies. Talk with your doctor about this medicine if you’re pregnant or planning on it.

          See the FDA package insert
          Alcohol
          No specific alcohol-related info.No specific alcohol-related info.
          Food
          • Can be taken with or without food.
          • Can take with or without food.
          • Try to take it on an empty stomach. If this gives you an upset stomach, take it with food.
          Kidneys and liver
          No specific kidneys and liver-related info.No specific kidneys and liver-related info.
          Sex
          No specific sex-related info.No specific sex-related info.
          Sleep
          No specific sleep-related info.No specific sleep-related info.
          Weight
          No specific weight-related info.No specific weight-related info.
          Upsides and benefits
          AzithromycinPenicillin
          • Available in different forms: tablet, capsule, and suspension.
          • Less resistance seen in bacteria to this antibiotic. Your doctor may run tests to see which antibiotics will kill the bacteria causing your infection.
          • Can be taken with or without food.
          • Available in generic.
          • Used to treat many types of bacterial infections.
          • Available in different forms: tablet, capsule and suspension.
          • Available in generic.
          • Used to treat many types of bacterial infections.
          Downsides and risks
          AzithromycinPenicillin
          • Must space out antacids by at least 2 hours.
          • Has to be used with caution in people who've had liver disease.
          • Can't be used in people who've had myasthenia gravis.
          • Must be used with caution in people who are on medications to thin the blood (anticoagulants) because of increased risk of bleeding.
          • Can cause abdominal pain, diarrhea, vomiting, and nausea.
          • Many bacteria have developed resistance. Your doctor may run tests to see if Penicillin will work on your infection.
          • Can make birth control pills less effective.
          • Best taken on an empty stomach, but can cause stomach upset and diarrhea.
          Tips from our pharmacists for people taking the medication
          AzithromycinPenicillin
          • Take the medication exactly how your doctor tells you to.
          • Space out any antacids with magnesium or aluminum by at least 2 hours.
          • Can take with or without food.
          • Can cause diarrhea, nausea or vomiting.
          • Take this medication exactly how your doctor tells you to.
          • If you're taking birth control pills, this medication can make them less effective.
          • Try to take it on an empty stomach. If this gives you an upset stomach, take it with food.
          • Can cause diarrhea, nausea or vomiting.
          Learn more
          More about AzithromycinSide effectsReviews & ratingsAlternativesFDA package insert
          More about PenicillinSide effectsReviews & ratingsAlternativesFDA package insert