Principen vs. Keflex

Are Principen and Keflex the Same Thing?

Principen (ampicillin) and Keflex (cephalexin) are antibiotics used to treat many different types of infections caused by bacteria.

Keflex is also used before dental procedures in patients identified with certain heart-related conditions to prevent bacterial infections of the heart known as endocarditis.

Principen and Keflex are different types of antibiotics. Principen is a penicillin-type antibiotic and Keflex is a cephalosporin antibiotic.

Side effects of Principen and Keflex that are similar include nausea, vomiting, abdominal or stomach upset/pain, diarrhea, vaginal itching or discharge, or headache.

Side effects of Principen that are different from Keflex include mouth/tongue sores, oral thrush (white patches inside your mouth or throat), or swollen, black, or "hairy" tongue.

Side effects of Keflex that are different from Principen include dizziness, tiredness, joint pain, itching, swelling, and rash.

What Are Possible Side Effects of Principen?

Common side effects of Principen include:

  • nausea,
  • vomiting,
  • stomach pain,
  • diarrhea,
  • vaginal itching or discharge,
  • headache,
  • mouth/tongue sores,
  • thrush (white patches inside your mouth or throat), or
  • swollen, black, or "hairy" tongue.

Tell your doctor if you have rare but very serious side effects of Principen including:

  • dark urine,
  • persistent nausea or vomiting,
  • yellowing eyes or skin,
  • easy bruising or bleeding, or
  • persistent sore throat or fever.

What Are Possible Side Effects of Keflex?

Common side effects of Keflex include:

  • diarrhea,
  • dizziness,
  • tiredness,
  • headache,
  • stomach upset,
  • abdominal pain,
  • joint pain,
  • vaginal itching or discharge,
  • nausea,
  • vomiting,
  • itching,
  • swelling, and
  • rash.

What Is Principen?

Principen (ampicillin) is a penicillin-type antibiotic used to treat many different types of infections caused by bacteria, such as ear infections, bladder infections, pneumonia, gonorrhea, and E. coli or salmonella infection. Principen is available in generic form.

What Is Keflex?

Keflex (cephalexin) is a cephalosporin antibiotic prescribed to treat bacterial infections. Keflex is also used before dental procedures in patients identified with certain heart-related conditions to prevent bacterial infections of the heart known as endocarditis. Keflex is available as a generic drug.

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What Drugs Interact With Principen?

Principen may interact with allopurinol, methotrexate, sulfa drugs, or tetracycline antibiotics. Tell your doctor all medications you are taking. Principen should be used only when prescribed during pregnancy. This medication passes into breast milk. Consult your doctor before breastfeeding.

What Drugs Interact With Keflex?

Keflex and amoxicillin may interact with probenecid and blood thinners.

Keflex may also interact with metformin.

How Should Principen Be Taken?

The usual oral dose range of Principen for most infections is 250 to 500 mg 4 times daily for 7-14 days. To treat gonorrhea, a single 3.5 g dose is administered along with probenecid.

How Should Keflex Be Taken?

Keflex dosage depends on the condition being treated. Keflex should be used with caution in patients who have kidney disease and those who report a history of penicillin allergy.

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References
SOURCE:

DailyMed. Principen (ampicillin) Product Information.

https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=da8da9c0-fa46-40d3-82c6-1a18ffa1b585

Dailymed. Keflex Product Information.

https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=68fba58a-7748-4581-8432-f5286c46d90a

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