Keflin

Keflin: Uses, Dosage, Side Effects, Interactions

Introduction

Keflin, also known as cephalothin, is a first-generation cephalosporin antibiotic widely used to treat various bacterial infections. It is a semisynthetic derivative of the natural compound cephalosporin C, which was isolated from the fungus Acremonium (formerly known as Cephalosporium). Keflin belongs to the class of penicillins and is renowned for its penicillinase-resistant properties, making it effective against certain penicillin-resistant bacteria.

Medical Uses

Keflin is primarily indicated for the treatment of the following bacterial infections caused by susceptible strains:

Keflin has been shown to be effective against a wide range of gram-positive and gram-negative bacteria, including Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Klebsiella, and Proteus species [1].

Dosage

The dosage of Keflin varies depending on the type and severity of the infection, the patient’s age, weight, and renal function. The standard adult dosage for most infections is 1-2 grams administered intravenously or intramuscularly every 6-8 hours. For severe infections, higher doses of up to 4 grams per day may be prescribed.

Dosage adjustments may be necessary for patients with impaired renal function. Pediatric dosages are typically calculated based on body weight, with the recommended dose ranging from 25-100 mg/kg per day, divided into multiple doses [2].

Side Effects

Like other antibiotics, Keflin can cause a range of side effects, including:

Common Side Effects:

  • Gastrointestinal disturbances (e.g., nausea, vomiting, diarrhea)
  • Skin rash or itching
  • Injection site pain or inflammation
  • Fever or chills

Severe Side Effects:

  • Severe allergic reactions (e.g., anaphylaxis, angioedema)
  • Pseudomembranous colitis (caused by Clostridioides difficile)
  • Nephrotoxicity (kidney damage)
  • Hepatotoxicity (liver damage)
  • Blood disorders (e.g., agranulocytosis, hemolytic anemia)

Patients should seek immediate medical attention if they experience any severe side effects or signs of an allergic reaction [3].

Drug Interactions

Keflin may interact with other medications, including:

  • Anticoagulants (e.g., warfarin): Increased risk of bleeding
  • Aminoglycosides (e.g., gentamicin): Increased risk of nephrotoxicity
  • Probenecid: Decreased elimination of Keflin, leading to higher blood levels

It is essential to inform healthcare professionals about all medications, supplements, and herbal products being taken to prevent potential interactions.

Precautions and Warnings

Keflin should be used with caution in the following situations:

  • Penicillin allergy: Keflin should not be used in patients with a history of severe allergic reactions to penicillins or cephalosporins.
  • Renal impairment: Dosage adjustments may be required in patients with reduced kidney function.
  • Pregnancy and breastfeeding: Keflin should only be used if the potential benefits outweigh the risks, as it can cross the placenta and enter breast milk.
  • Gastrointestinal disease: Keflin may exacerbate conditions like colitis or enteritis.

Patients should report any adverse effects or concerning symptoms to their healthcare provider.

Pharmacology and Mechanism of Action

Keflin is a bactericidal antibiotic that works by inhibiting the synthesis of bacterial cell walls. It binds to and inactivates the penicillin-binding proteins (PBPs) involved in the final stages of cell wall synthesis, leading to weakening and eventual cell lysis and death.

Keflin is resistant to penicillinases, enzymes produced by certain bacteria that can degrade and inactivate penicillin antibiotics. This resistance allows Keflin to be effective against some penicillin-resistant strains of bacteria [4].

Pharmacokinetics

Keflin exhibits the following pharmacokinetic properties:

  • Absorption: After intramuscular injection, Keflin is rapidly absorbed, with peak serum concentrations occurring within 30 minutes to 1 hour.
  • Distribution: Keflin is widely distributed throughout body tissues and fluids, including cerebrospinal fluid, pleural fluid, and synovial fluid.
  • Metabolism: Keflin is not extensively metabolized and is primarily excreted unchanged in the urine.
  • Elimination: The average plasma half-life of Keflin is approximately 0.5-1.2 hours, with most of the drug being eliminated through glomerular filtration in the kidneys.

Adjustments to the dosage regimen may be necessary in patients with impaired renal function to prevent accumulation and potential toxicity.

Formulations

Keflin is available in several formulations, including:

KEFLIN® Neutral

A sterile powder for reconstitution and intravenous or intramuscular injection.

Keflin 200 MG Tablet

An oral tablet formulation containing 200 mg of cephalothin.

Keflin Neutral Powder for Injection

A sterile powder for reconstitution and intramuscular or intravenous administration.

Administration

Intravenous Administration

Keflin can be administered intravenously as a direct injection or as a continuous or intermittent infusion. The reconstituted solution should be inspected for particulate matter and discoloration before administration.

Intramuscular Injection

Keflin can be administered by deep intramuscular injection into a large muscle mass, such as the gluteus or lateral aspect of the thigh. The injection site should be rotated to minimize discomfort and potential tissue damage.

Development and History

Keflin was first synthesized in the late 1960s by researchers at Eli Lilly and Company. It was derived from the natural compound cephalosporin C, which was isolated from the fungus Acremonium (formerly known as Cephalosporium) [5].

Keflin was approved for medical use in the United States in 1964 and became one of the first cephalosporin antibiotics available for clinical use. Its introduction provided an alternative to penicillin for the treatment of infections caused by penicillin-resistant bacteria.

Chemical Properties

The chemical name of Keflin is sodium (6R,7R)-3-acetoxymethyl-7-[(2R)-2-amino-2-phenylacetamido]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate, with the molecular formula C 16H 15N 2O 6S 2Na and a molecular weight of 418.42 g/mol.

Keflin exists as a zwitterionic compound, with both cationic and anionic centers. The anionic form, known as cefalotin(1-), has a chemical formula of C 16H 15N 2O 6S 2– and a molecular weight of 397.40 g/mol [6].

Comparison with Other Antibiotics

Keflin is a first-generation cephalosporin antibiotic and is structurally related to penicillins. It shares some similarities with penicillins in terms of its antibacterial spectrum, but it also exhibits some unique properties:

  • Keflin is resistant to degradation by many penicillinase enzymes produced by certain bacteria, making it effective against some penicillin-resistant strains.
  • Keflin has a broader spectrum of activity compared to penicillins, being effective against both gram-positive and gram-negative bacteria.
  • Compared to later-generation cephalosporins, Keflin has a narrower spectrum of activity and is less effective against certain gram-negative bacteria.

The choice between Keflin and other antibiotics depends on the specific type of infection, the susceptibility of the causative bacteria, and the patient’s medical history and potential for adverse reactions.

Research Studies

Numerous research studies have been conducted to evaluate the efficacy, safety, and pharmacokinetics of Keflin. Here are a few examples:

  • A randomized controlled trial compared the efficacy and safety of Keflin and cefazolin in the treatment of skin and soft tissue infections. The study found that both antibiotics were equally effective, but Keflin had a higher incidence of gastrointestinal side effects [7].
  • A pharmacokinetic study evaluated the distribution of Keflin in various body fluids and tissues after intravenous administration. The results showed that Keflin penetrates well into cerebrospinal fluid, synovial fluid, and bone [8].
  • A retrospective study analyzed the safety and efficacy of Keflin in the treatment of febrile neutropenic patients with cancer. The study found that Keflin, in combination with an aminoglycoside, was an effective empiric therapy for this patient population [9].

These and other studies have contributed to our understanding of Keflin‘s clinical applications, dosing, and potential adverse effects.

Manufacturing and Marketing

Keflin was originally developed and marketed by Eli Lilly and Company under the brand name KEFLIN®. However, after its patent expired, several pharmaceutical companies have produced and marketed generic versions of cephalothin.

Some major manufacturers and trade names of Keflin include:

  • KEFLIN® (Eli Lilly and Company)
  • Cephalothin (Sandoz, Teva, and others)
  • Cephton (Merck) Keflin