Compare Amoxicillin vs. Penicillin

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

Amoxil
(Amoxicillin)

Penicillin Vk
(Penicillin)

Treats bacterial infections. Amoxil (Amoxicillin) is a good and cheap antibiotic to treat many types of bacterial infections. However, many bacteria are resistant to this medication.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
5.0025641025641026Amoxicillin
Reviews for Amoxil (Amoxicillin)
62%
of people say Amoxil (Amoxicillin) is worth it
45%
say it works well
14%
say it's a big hassle
Reviews for Penicillin Vk (Penicillin)
71%
+9% vs. Amoxil (Amoxicillin)
52%
+7% vs. Amoxil (Amoxicillin)
12%
+2% vs. Amoxil (Amoxicillin)
Side effects
AmoxicillinPenicillin

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

More about Amoxicillin 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
AmoxicillinPenicillin
Amoxil (Amoxicillin) is an antibiotic. It kills bacteria and prevents them from reproducing and making their own protective covering.Penicillin Vk (Penicillin) is an antibiotic. It kills bacteria by preventing them from making their own protective covering.
Type of medication
AmoxicillinPenicillin
Antibiotic
Penicillin
Prescription only
Antibiotic
Penicillin
Prescription only
Available as
AmoxicillinPenicillin
  • Pill
  • Chewable tablet
  • Liquid
  • Pill
Used for (click to learn more)
AmoxicillinPenicillin
Risk factors for serious side effects
AmoxicillinPenicillin
  • Long antibiotic treatment period
  • History of penicillin allergies
  • Using oral birth control pills
    Detailed Amoxil (Amoxicillin) risks & warnings »
        • Prior severe allergic reaction to Penicillin Vk (Penicillin)
        Detailed Penicillin Vk (Penicillin) risks & warnings »
        Pregnancy category
        AmoxicillinPenicillin
        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
        • Take with food to decrease upsetting your stomach (nausea, vomiting).
        • 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
        AmoxicillinPenicillin
        • Available in different forms: tablet, capsule, and suspension.
        • 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
        AmoxicillinPenicillin
        • Suspension must be stored in the fridge.
        • Can make birth control pills and live vaccines less effective.
        • Many bacteria have developed resistance to this antibiotic.
        • Can cause diarrhea.
        • 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
        AmoxicillinPenicillin
        • Finish all of the medicine your doctor gives you, even if you start to feel better. Stopping it early can cause the bacteria to develop resistance, making the medicine ineffective.
        • If you're taking birth control pills, this medication may make them less effective.
        • Take with food to decrease upsetting your stomach (nausea, vomiting).
        • If you're giving the suspension, you can mix it with a cold drink, but make sure to take it right away.
        • Keep the suspension form in the fridge. All other forms should be kept at room temperature.
        • You may have loose stool when taking this medicine, but it should get better soon after finishing the course. If the diarrhea worsens, tell your doctor.
        • 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 AmoxicillinSide effectsReviews & ratingsAlternativesFDA package insert
        More about PenicillinSide effectsReviews & ratingsAlternativesFDA package insert