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Ampicillin vs amoxicillin

Ampicillin vs amoxicillin 
Ampicillin vs amoxicillin

Ampicillin vs amoxicillin can be described as antibiotics employed in the treatment of many bacteria-related infections. Both are recognized through the U.S. Food and Drug Administration (FDA). Antibiotics are antimicrobial and are utilized to treat infections caused by bacteria. They are not helpful in the management of viral diseases (like the flu or the common cold, and other viral-born illnesses).

Ampicillin and amoxicillin are both parts of the class of medicines known as penicillin (or aminopenicillin) or beta-lactam antimicrobials. They stop bacteria from creating cell walls which cause the destruction of bacteria. Both antibiotics can be used to treat various types of bacteria-related diseases 

Although ampicillin and amoxicillin are both penicillin antibiotics, they are not exactly the same. Read on to find out more about ampicillin and amoxicillin.

The primary difference between ampicillin and amoxicillin

Ampicillin is a penicillin-based antibiotic. This antibiotic is employed to fight both Gram-positive and gram-negative bacterial strains. The name for ampicillin is Principen but Principen is no anymore available as a brand-name medication. The drug is available in generic form ampicillin, in an oral capsule, or an injection. Ampicillin is also available as an injectable form under the name Unasyn which has ampicillin in addition to Sulbactam (to combat resistance to antibiotics). Unasyn will no longer be available under the brand name, but it is available in generic ampicillin/sulbactam form only.

It is also known as a penicillin-based antibiotic. It has chemical similarities to ampicillin and provides a broad range of action against gram-positive and negative bacteria.

Amoxicillin’s one of the brand names is Amoxil, however, Amoxil is no longer commercially available. It is available in the generic version of amoxicillin. Amoxicillin is usually prescribed as capsules of amoxicillin in adults. It can also be used as a suspension to children. It can also be used with clavulanic acid (which stops antibiotic resistance) in the form of medicine known as Augmentin.

It’s crucial to remember that when you are taking an antibiotic, it is important to adhere to the directions and complete the entire course even if you feel better prior to the treatment ends. If, however, you’ve taken your antibiotic for a few days and aren’t feeling better or are experiencing worse, speak to your physician for guidance.

Main differences between ampicillin and amoxicillin
Ampicillin Amoxicillin
Drug class Penicillin (beta-lactam) antibiotic Penicillin (beta-lactam) antibiotic
Brand/generic status Generic Generic
What is the brand name? Principen (no longer available in the brand name) Amoxil, Trimox (no longer available in the brand name)
Dosage Forms Ampicillin: capsule, injection

Unasyn: (ampicillin-sulbactam): injection

Amoxicillin: capsule, suspension, tablet, chewable tablet

Augmentin: (amoxicillin-clavulanate): tablet, chewable tablet, suspension

Prevpac: a course of treatment containing amoxicillin capsules in combination with lansoprazole and clarithromycin (used for stomach ulcers caused by H. pylori bacteria)

Dosage Example: ampicillin 500 mg every 6 hours for 10-14 days Example: amoxicillin 500 mg 3 times a day for 10 days
 Length of treatment 10-14 days; may vary 7-10 days; may vary
Typically uses the medicine Adults and children Adults and children

 Primary conditions treated with ampicillin and amoxicillin

Ampicillin is a treatment for bacteria-related infections, including:

  • Genitourinary tract infections, including gonorrhea, are caused by P. mirabilis, enterococci, Shigella, S. typhosa, and other Salmonella and non-penicillinase-producing N. gonorrhoeae
  • Respiratory tract infections caused by non-penicillinase-producing influenza and staphylococci, and streptococci including Streptococcus pneumonia
  • Gastrointestinal tract infections triggered by Shigella, S. Typhosa and various Salmonella, E. Coli, P. mirabilis, and enterococci
  • Meningitis is caused in part by Meningitidis

Amoxicillin is used for treating many infections caused by bacteria:

  • Ear inflammations (otitis media) or nose infections or throat infections that are caused by specific strains of Streptococcus pneumoniae Staphylococcusspp. and Haemophilus influenzae
  • Urinary tract infections is caused by Escherichia Coli, P. mirabilis, or Enterococcus Faecalis
  • Skin conditions or infections that are caused by specific varieties from Streptococcus, Staphylococcus (such as Staphylococcus aureus), or E. coli
  • The lower respiratory tract infection is caused by specific varieties that are Streptococcus, Streptococcus pneumoniae, Staphylococcus, or H. influenzae
  • Acute, uncomplicated gonorrhea that affects males and females is caused by Neisseria Gonorrhoeae
  • Elimination of Pylorito decreases the chance of duodenal ulcer recurrence.
  • Amoxicillin may also be used in triple therapy using the combination of lansoprazole as well as clarithromycin (as Prevpac) for patients suffering from Pylori infections and duodenal ulcers.

Antibiotics such as ampicillin and amoxicillin should be only employed in cases of bacterial infection when they are deemed appropriate by your medical professional.


Ampicillin is more effective than amoxicillin?

Studies that compare the two drugs aren’t recent or have only in a small sample. A study in 1985 examined the effectiveness of both drugs to treat ear infections in children and discovered both medications to be equally effective. Amoxicillin was more well-tolerated, with fewer side reactions than ampicillin.

Ampicillin alone is not used more often than previously before because of the rise of resistance to the drug. Today, ampicillin is more frequently prescribed. But, ampicillin when combined along with Sulbactam (Unasyn) is usually administered by injection within a medical setting. Sulbactam is a beta-lactamase inhibitor that assists in the prevention of resistance to drugs. In the setting of outpatients, it’s similar to the patient who is taking Augmentin which is amoxicillin, and clavulanic acid, which is a beta-lactamase inhibitor.

The most effective medicine can be identified by your physician who will be able to diagnose your condition as either viral or bacterial. If the problem is bacterial, the choice about which antibiotic to choose will be determined by the bacteria is responsible for the illness (if it is known or, in the event that it is not known and suspected, the type of bacteria believed to be the cause). Your doctor will examine your complete medical history and other medical conditions you may have as well as other medications you are taking that could be incompatible with amoxicillin or ampicillin.


Cost and coverage comparisons of ampicillin and. amoxicillin

The typical ampicillin prescription would include 40 or 500 mg pills. The cost out of pocket is about $30. Utilizing the SingleCare card to buy ampicillin could lower the cost by less than.

Amoxicillin is a common prescription. is 30capsules of 500 mg. The price out-of-pocket could be higher than $20. If you have the amoxicillin SingleCare discount coupon, you can pay as little as $5.

  Ampicillin Amoxicillin
Typically covered by insurance? Yes Yes
Typically covered by Medicare Part D? Yes Yes
Standard dosage 40, 500 mg capsules 30, 500 mg capsules
Typical Medicare Part D copay $0-$1 $0-$1
Cost $20+ $5+

Common side effects of ampicillin vs amoxicillin

The most frequent adverse effects of ampicillin and amoxicillin are a result of penicillin sensitivity. These are more likely to happen for patients who previously experienced hypersensitivity to penicillins, as well as in those who have an allergy history or asthma. The most common side effects include nausea, vomiting, diarrhea, and skin rash/hypersensitivity reactions. Anaphylactic reactions with severe consequences require urgent treatment.

In general, treatment with antibiotics could make you more susceptible to a yeast infection. Discuss with your healthcare professional whether you should use an antibiotic.

This isn’t an exhaustive list of possible potential side effects that can be experienced. Talk to your healthcare professional for a complete list of adverse reactions.

  Ampicillin Amoxicillin
Side effect Applicable? Frequency Applicable? Frequency
Diarrhea Yes Not reported Yes >1%
Nausea Yes Not reported Yes >1%
Abdominal pain Yes Not reported Yes Not reported
Vomiting Yes Not reported Yes >1%
Rash Yes Not reported Yes >1%


Amoxicillin vs amoxicillin drug interactions

Ampicillin and amoxicillin share the same list of interactions due to the fact that they’re structurally identical medications.

Amoxicillin or ampicillin taken in conjunction with an anticoagulant medication like warfarin could cause bleeding. Patients must be closely monitored when taking this combination. Additionally, allopurinol, the medication used to treat gout, when used in conjunction with ampicillin and amoxicillin could increase the likelihood of developing a skin rash.

Oral contraceptives (also called birth control pills) can be less effective when used together with antibiotics like amoxicillin or ampicillin. Ask your physician about the need for alternative birth controls (such as condoms) when you take an antibiotic.


Drug Drug class Ampicillin Amoxicillin
Warfarin Anticoagulant Yes Yes
Allopurinol Xanthine oxidase inhibitor (used for gout) Yes Yes
Oral contraceptives Oral contraceptives Yes Yes
Probenecid Uricosuric Yes Yes
Vivotif Berna Typhoid vaccine (live) Yes Yes
Bupropion Aminoketone antidepressant Yes Yes
Methotrexate Antimetabolite Yes Yes
Magnesium citrate Saline laxative Yes Yes

Amoxicillin vs ampicillin warnings

  • Clostridium difficile associated diarrhea is a common occurrence by many antibiotics and may vary in severity, ranging from mild diarrhea to death from colitis. This type of diarrhea can happen when antibiotics are used (even some months after). If you notice nausea, diarrhea, or abdominal pain, as well as fever, consult your physician immediately.
  • If you’ve been a victim with an allergy reaction to penicillins avoid taking amoxicillin or ampicillin.
  • Rarely fatal hypersensitivity reactions (anaphylaxis) have been reported in penicillins. This can also happen to patients being treated with a cephalosporin, such as Cephalexin. Patients shouldn’t be prescribed amoxicillin or ampicillin if there is a prior reaction. If you experience an allergic reaction the ampicillin or amoxicillin must be taken off immediately and must seek immediate treatment.
  • Amoxicillin or ampicillin is not recommended to treat an infection that is bacterial. Utilizing antibiotics to treat an infection caused by viruses is not a cure for the illness as well as could cause resistance to antibiotics.
  • The long-term use of antibiotics can cause fungal infections that will require to be treated.
  • Patients who suffer from both gonorrhea and Syphilis also require appropriate penicillin parenterally (penicillin G) treatment.
  • In spite of treatment with ampicillin, patients might still require surgery, especially when there are a staphylococcal infections.

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