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.
Reviews & ratings
Filter group. All currently selected
Filter group. All currently selected
5.45Azithromycin
Reviews for Azithromycin
74%
of people (All ages) say Azithromycin is worth it
59%
say it works well
11%
say it's a big hassle
909 reviews
Have you used Zithromax (azithromycin)?
Worth itNot sureNot worth it
Reviews for Penicillin
71%
+3% better vs. Azithromycin
52%
+7% better vs. Azithromycin
12%
+1% better vs. Azithromycin
1297 reviews
Have you used Penicillin Vk (penicillin)?
Worth itNot sureNot worth it
Side effects
AzithromycinPenicillin
  • Diarrhea 5%
  • Nausea 3%
  • Abdominal pain 3%
  • Vomiting 6%
  • Rash 2%
  • Vaginitis 2%
More 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
Prescription onlyPrescription only
Available as
AzithromycinPenicillin
  • Pill
  • Liquid
  • Eye drops
  • Pill
Used for
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

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

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.

Food
AzithromycinPenicillin
  • Can take with or without food.
  • Can be taken with or without food.
No food related info.
Kidneys and liver
AzithromycinPenicillin
  • There have been reports of liver damage that can require hospitalization or can cause death. These have been rare. Talk to your doctor if you notice pain in your abdomen, loss of appetite, yellowing of your skin or eyes, or dark colored urine.
No kidneys and liver related info.
Pain
AzithromycinPenicillin
  • Can cause abdominal pain, diarrhea, vomiting, and nausea.
No pain related info.
Upsides and benefits
AzithromycinPenicillin
  • Available in generic.
  • Available in different forms: tablet, capsule, and suspension.
  • Used to treat many types of bacterial infections.
  • 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.
  • Available in different forms: tablet, capsule and suspension.
  • 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.
  • Can cause diarrhea, nausea or vomiting.
  • Space out any antacids with magnesium or aluminum by at least 2 hours.
  • Can take with or without food.
  • 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
Have you used Zithromax (azithromycin)?
Worth itNot sureNot worth it
More about PenicillinSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Penicillin Vk (penicillin)?
Worth itNot sureNot worth it