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Amoxicillin oral capsule vs. penicillin V potassium oral tablet: A detailed guide

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FAQCostBrand namesUsesDosageSide effectsWarnings
Amoxicillin oral capsule and penicillin V potassium oral tablet are prescription drugs used to treat certain bacterial infections. For example, both medications are used to treat strep throat or a tooth infection in certain cases.
Medically reviewed by Melissa Badowski, PharmD, MPH, FCCP
Updated on

This article explains how amoxicillin oral capsule and penicillin V potassium oral tablet are similar and different. You can view detailed articles about amoxicillin and penicillin V if you’d like more information about these drugs.

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Questions about amoxicillin and penicillin V

Below, you’ll find answers to some common questions about amoxicillin oral capsule and penicillin V potassium oral tablet.

Is amoxicillin a penicillin? Is it safe to take amoxicillin if I have a penicillin allergy?

Amoxicillin is a penicillin drug, and it should not be taken if you have a penicillin allergy.

Penicillins are a group of antibiotic drugs with very similar structures. If you experience an allergic reaction from taking a penicillin drug, you’ll likely have the same reaction with any penicillin drug.

Penicillin allergy can sometimes overlap with an allergy to cephalosporins. These are another group of antibiotic drugs. Examples include ceftriaxone and cefepime.

If you have a penicillin allergy, your doctor likely won’t prescribe amoxicillin oral capsule or penicillin V potassium oral tablet. Instead, they can discuss safer antibiotics that can work to treat your infection.

See the “Allergic reaction” section below for more about amoxicillin and penicillin allergy.

How do amoxicillin and penicillin compare vs. ampicillin?

Amoxicillin, penicillin, and ampicillin are similar drugs. They’re all penicillin antibiotics used to treat certain bacterial infections. One key difference is that, unlike amoxicillin and penicillin, ampicillin may be useful for treating infections in the genitourinary tract, including gonorrhea.

Some common side effects shared by these drugs include nausea, vomiting, and diarrhea. A rare but serious side effect is Clostridioides difficile (C. diff)-associated diarrhea.

Talk with your doctor or pharmacist to learn more about how amoxicillin, penicillin, and ampicillin compare.

Allergic reaction

For some people, amoxicillin or penicillin can cause an allergic reaction. But it’s not clear whether this side effect occurred in studies of amoxicillin oral capsule and penicillin V potassium oral tablet.

In general, symptoms of allergic reaction can be mild or serious. You can learn more about possible symptoms in this article.

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to amoxicillin, your doctor may recommend taking a different medication instead.

Cost of amoxicillin and penicillin V

As with the cost of other medications, the cost of amoxicillin and penicillin V can vary. Their price may be affected by:

  • whether they’re covered by health insurance, if you have coverage
  • the pharmacy they’re purchased from
  • the quantity prescribed

Coupons and cost savings

To view drug prices when Optum Perks coupons are applied, see the coupon pages for amoxicillin and penicillin V. You can also check with your doctor, pharmacist, or insurance provider.

The options described in this article may also help you save on your prescription.

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Brand-name versions

Here’s a summary about brand-name versions of amoxicillin oral capsule and penicillin V potassium oral tablet:

 Amoxicillin oral capsulePenicillin V potassium oral tablet
Active ingredientamoxicillinpenicillin
Available as a brand-nameyes (Amoxil)no

A generic medication is an identical copy of the active ingredient in a brand-name medication. (An active ingredient is what makes a medication work.) 

Generics usually cost less than brand-name drugs. And they’re thought to be as safe and effective as the brand-name version.

Uses of amoxicillin and penicillin V

Here’s a summary of amoxicillin oral capsule’s and penicillin V potassium oral tablet’s approved uses:

 Amoxicillin oral capsulePenicillin V potassium oral tablet
Approved to treat• upper respiratory bacterial infections of the ear, nose, or throat
• bacterial infections in the genitals or urinary system
• certain bacterial skin infections
• bacterial infections of the lower respiratory tract
Helicobacter pylori (H. pylori) infection and duodenal ulcer disease, used with other medications*
• other bacterial infections
strep throat
scarlet fever
• mild erysipelas (a bacterial skin infection)
• mild to moderate respiratory infections caused by pneumococcal bacteria
• skin infections caused by staphylococcus bacteria
• certain types of gingivitis and pharyngitis
• other bacterial infections
Prescribed toadults and children of any ageadults and children ages 12 years and older

* Amoxicillin is approved to treat this condition in adults only.

Amoxicillin oral capsule is prescribed together with lansoprazole and sometimes clarithromycin, for treating H. pylori infection and duodenal ulcer disease.

Doctors may not prescribe amoxicillin oral capsule or penicillin V potassium oral tablet in certain situations. For example, they’ll likely order a test that checks which antibiotics may work to treat your infection. This is called a susceptibility test. If the test shows your infection isn’t susceptible (likely to be successfully treated by) to amoxicillin or penicillin, your doctor will prescribe a different antibiotic that’s effective for your infection.

Doctors may also prescribe amoxicillin or penicillin for infections not listed in the chart above, if the susceptibility test shows your infection may respond to treatment with either medication. For example, amoxicillin may be prescribed for a tooth infection if testing shows the drug could work to treat the infection.

If you’d like to know more about taking either medication for your condition, ask your doctor. They can recommend whether amoxicillin oral capsule or penicillin V potassium oral tablet is an option to consider.

Dosage of amoxicillin and penicillin V

Below is dosage information for the conditions that both amoxicillin oral capsule and penicillin V potassium oral tablet are prescribed to treat. These dosages are provided by the drugmakers of amoxicillin and penicillin V.

If your doctor prescribes either medication, you should follow the dosage they prescribe. They’ll advise the dosage that’s best for your condition. Do not adjust your dosage without first talking with your doctor.

To find detailed dosage information for all conditions that amoxicillin oral capsule and penicillin V potassium oral tablet treat or help prevent, see these articles about amoxicillin dosage and penicillin V dosage.

Amoxicillin’s dosage

Below is a summary of amoxicillin oral capsule’s recommended dosages in adults and children ages 3 months and older who weigh more than 40 kilograms (about 88 pounds). Drug strength is measured in milligrams (mg).

ConditionHow it’s takenRecommended dose
certain upper respiratory infections by mouth500 mg every 12 hours; or 250 mg every 8 hours
certain lower respiratory infectionsby mouth875 mg every 12 hours; or 500 mg every 8 hours
certain bacterial skin infectionsby mouth500 mg every 12 hours; or 250 mg every 8 hours

The table below details amoxicillin dosing for children ages 3 months and older who weigh 40 kg (about 88 pounds) or less. It also includes dosing information for amoxicillin when used for children less than 3 months of age. For these uses, your child’s doctor will calculate the dose based on your child’s body weight. Doses are written as milligrams per kilogram per day (mg/kg/day).

ConditionHow it’s takenRecommended dose
certain upper respiratory infections, in children ages 3 months and older who weigh 40 kg or lessby mouth25 to 45 mg/kg/day, divided into two doses per day (every 12 hours); or 20 to 40 mg/kg/day, divided into three doses (every 8 hours)
certain lower respiratory infections, in children ages 3 months and older who weigh 40 kg or lessby mouth45 mg/kg/day, divided into two doses per day (every 12 hours); or 40 mg/kg/day, divided into three doses (every 8 hours)
certain bacterial skin infections, in children ages 3 months and older who weigh 40 kg or lessby mouth25 to 45 mg/kg/day, divided into two doses (every 12 hours); or 20 to 40 mg/kg/day, divided into three doses (every 8 hours)
certain upper respiratory, lower respiratory, or skin infections due to bacteria, in children less than 3 months of ageby mouthup to 30 mg/kg/day, divided into two doses (every 12 hours)

Penicillin V’s dosage

Below is a summary of penicillin V potassium oral tablet’s recommended dosages in adults and children ages 12 years and older. Strength is measured in mg.

ConditionHow it’s takenRecommended doseFrequency
certain upper respiratory infectionsby mouth125 to 250 mgevery 6 to 8 hours for 10 days
certain lower respiratory infectionsby mouth250 to 500 mgevery 6 to 8 hours
certain bacterial skin infectionsby mouth250 to 500 mgevery 6 to 8 hours

Side effects of amoxicillin and penicillin V

Amoxicillin oral capsule and penicillin V potassium oral tablet may cause mild or serious side effects. Some of the more common mild side effects of each drug are listed below. Serious side effects of amoxicillin and penicillin V are also listed.

Keep in mind that your side effects may differ from those listed below. They can vary based on your overall health, any other medications you take, and your age.

This article doesn’t include all possible side effects of these medications. To find more information, you can view the prescribing information for amoxicillin oral capsule and penicillin V potassium oral tablet. You can also check out these articles about amoxicillin side effects and penicillin V side effects.

Mild side effects

Below are some of the mild side effects reported with amoxicillin oral capsule and penicillin V:

 Amoxicillin oral capsulePenicillin V
diarrhea
nausea and vomiting
skin rash
upset stomach
black hairy tongue

Serious side effects

Below are serious side effects reported with amoxicillin oral capsule and penicillin V potassium oral tablet:

 Amoxicillin oral capsulePenicillin V potassium oral tablet
C. diff-associated diarrhea
severe skin reactions, including Stevens-Johnson syndrome
drug-induced enterocolitis syndrome 

For a lot of drugs, serious side effects are possible, but they’re not common. If you have serious side effects from amoxicillin or penicillin V, call your doctor right away. If your symptoms are severe or you’re having a medical emergency, call 911 or a local emergency number.

Warnings for amoxicillin and penicillin V

Some medications may not be recommended for you if you have certain factors affecting your health. These are referred to as a drug’s warnings.

Some people should not take amoxicillin oral capsule or penicillin V potassium oral tablet, and others should take either medication with caution.

Warnings for amoxicillin oral capsule and penicillin V potassium oral tablet are summarized below. Before taking either medication, talk with your doctor about your health conditions, past surgeries, and any medications you take. Your doctor can recommend whether either drug is safe for you.

Warnings

Warnings for amoxicillin oral capsule and penicillin V potassium oral tablet are summarized in the table below:

 Amoxicillin oral capsulePenicillin V potassium oral tablet
asthma
current mononucleosis infection
allergic reaction to either drug or any of their ingredients
allergic reaction to penicillin or cephalosporin drugs
currently pregnant or planning to become pregnant
currently breastfeeding or planning to breastfeed

You can view more detailed articles about amoxicillin and penicillin V if you’d like to know more about warnings for these drugs. You can also view the prescribing information for amoxicillin oral capsule and penicillin V potassium oral tablet.

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

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