What is the Difference Between Ciprofloxacin and Amoxicillin

The key difference between ciprofloxacin and amoxicillin is that ciprofloxacin is a fluoroquinolone antibiotic that is effective against some gram-positive and many gram-negative bacteria, while amoxicillin is a penicillin antibiotic primarily effective against gram-positive bacteria.

Ciprofloxacin and amoxicillin are two commonly prescribed antibiotics with different modes of action and activity spectra. Ciprofloxacin belongs to the fluoroquinolone antibiotic family, effective against gram-positive and gram-negative bacteria. In contrast, amoxicillin belongs to the penicillin antibiotic family and is most effective against gram-positive bacteria. When selecting the best therapeutical regimen for illnesses, it is necessary to understand the difference between ciprofloxacin and amoxicillin.

CONTENTS

1. Overview and Key Difference
2. What is Ciprofloxacin 
3. What is Amoxicillin
4. Similarities – Ciprofloxacin and Amoxicillin
5. Ciprofloxacin vs Amoxicillin in Tabular Form
6. Summary – Ciprofloxacin vs Amoxicillin

What is Ciprofloxacin?

Ciprofloxacin is a fluoroquinolone antibiotic frequently used to treat bacterial infections such as pneumonia and urinary tract infections caused by gram-positive and gram-negative bacteria. It prevents bacterial DNA replication and repair by inhibiting enzymes such as DNA gyrase and topoisomerase, consequently inhibiting the growth of the bacteria and preventing further infections.

Ciprofloxacin is available in various forms, including oral tablets, intravenous (IV) infusions, and topical formulations. It is readily absorbed with a 70-80% bioavailability in oral administrations. The antibiotic is metabolized in the liver by cytochrome P450 1A2 (CYP1A2), producing high plasma concentration and distribution volume. Ciprofloxacin is cleared from the body through both renal and biliary clearance.

What is Amoxicillin?

Amoxicillin is a common β-lactam antibiotic belonging to the penicillin family. It binds with the penicillin-binding proteins (PBPs) enzymes to inhibit cross-linking peptidoglycan chains in the bacterial cell wall (transpeptidation), consequently inhibiting the formation of the bacterial cell wall and resulting in bacterial cell death.

Amoxicillin is often used to treat gram-positive bacterial infections, such as respiratory system, urinary tract, skin and soft tissues, dental infections, and some sexually transmitted diseases. It is available in various formulations such as intravenous (IV), intramuscular infusions, and oral pills and solutions. Nevertheless, topical medications are not common with penicillin. It rapidly absorbs after oral administration, and bioavailability has proven to be higher when it is taken fasting. Furthermore, amoxicillin binds with serum proteins with a low affinity, is poorly metabolized by the liver, and is excreted primarily through renal clearance.

What are the Similarities Between Ciprofloxacin and Amoxicillin?

• Ciprofloxacin and amoxicillin are effective against some gram-positive bacteria, including certain strains of Streptococcus and Staphylococcus.
• Both antibiotics may result in side effects such as nausea and diarrhoea, and allergic reactions.
• They are vulnerable to antibiotic resistance acquired by bacteria.

What is the Difference Between Ciprofloxacin and Amoxicillin?

Ciprofloxacin and amoxicillin are frequently prescribed antibiotics for a broad spectrum of bacterial infections. However, there is a difference between ciprofloxacin and amoxicillin in various aspects. Ciprofloxacin, a fluoroquinolone antibiotic, inhibits bacterial DNA synthesis in gram-positive and gram-negative bacteria, which cause respiratory, urinary, gastrointestinal, skin, and sexually transmitted infections. In contrast, amoxicillin, a penicillin antibiotic, primarily inhibits bacterial cell wall synthesis in gram-positive bacteria, which causes respiratory, urinary, dental, and specific skin and soft tissue infections.

Ciprofloxacin is available in various forms, including IV infusion, oral tablets, and topical preparations, while amoxicillin is predominantly administered orally as tablets, chewable tablets, capsules, or suspensions. Moreover, ciprofloxacin is comparatively well metabolized in the liver, while amoxicillin is poorly metabolized, and a high amount of unchanged drug is excreted with urine. However, resistance development occurs with both antibiotics, with ciprofloxacin experiencing resistance in some bacterial strains due to widespread use, while the susceptibility of amoxicillin is affected by the production of β-lactamase enzymes.

The following table summarizes the difference between ciprofloxacin and amoxicillin.

Summary – Ciprofloxacin vs Amoxicillin

Ciprofloxacin and amoxicillin are two frequently prescribed antibiotics for bacterial infections. Nevertheless, the difference between ciprofloxacin and amoxicillin lies in their classification, mechanisms of action, spectra of activity, routes of administration, indications, and resistance development. Ciprofloxacin is a fluoroquinolone antibiotic that inhibits bacterial DNA synthesis, effective against a broad spectrum of bacteria, including gram-positive and gram-negative strains. Amoxicillin, a penicillin antibiotic, interferes with bacterial cell wall synthesis and primarily targets gram-positive bacteria with limited effectiveness against gram-negative strains. Ciprofloxacin is available in various forms, including oral, intravenous, and topical preparations, while amoxicillin is predominantly administered orally. Moreover, ciprofloxacin is often used for respiratory, urinary, gastrointestinal, skin, and sexually transmitted infections, while amoxicillin is commonly prescribed for respiratory, urinary, dental, and specific skin and soft tissue infections.

Reference:

1. Castle, Sharon S. “Amoxicillin.” xPharm: The Comprehensive Pharmacology Reference, 2007, pp. 1–6.
2. Thai, Tony, et al. “Ciprofloxacin.” National Library of Medicine.

Image Courtesy:

1. “Ciprofloxacin” By Fvasconcellos – Own work (Public Domain) via Commons Wikimedia
2. “Amoxicillin” By Fvasconcellos (talk · contribs) – Own work (Public Domain) via Commons Wikimedia