Cefazolin is a β-lactam type antibiotic belonging to the first generation cephalosporin class.
Cefazolin - Chemical Structure
Cefazolin is especially active against Gram-positive bacteria, while it is not very effective against Gram-negative bacteria.
Of all first-generation cephalosporins, cefazolin - when injected - is the least irritating.
Indications
For what it uses
The use of cefazolin is indicated for the treatment of infections caused by bacteria sensitive to the cefazolin itself, including:
- Airway infections;
- Genitourinary infections;
- Gynecological infections;
- Skin and soft tissue infections;
- Gastrointestinal infections;
- Eye infections;
- Otorhinolaryngological infections;
- Hepatobiliary infections;
- Osteoarticular infections;
- peritonitis;
- Septicemia;
- appendicitis;
- Bacterial endocarditis.
Furthermore, cefazolin can be used for the prophylaxis and treatment of surgical infections.
Warnings
Before starting cefazolin therapy it is necessary to have excluded any allergies towards other cephalosporins, penicillins or other β-lactam antibiotics.
In the event of allergic reactions, treatment with cefazolin should be discontinued immediately.
Caution should be exercised when administering cefazolin to patients who have suffered from gastrointestinal disorders, particularly colitis.
Treatment with cefazolin may favor the development of bacteria resistant to the antibiotic itself, or it may favor the appearance of clostridial superinfections responsible for the onset of pseudomembranous colitis. Mild cases of pseudomembranous colitis usually resolve with simple treatment interruption. The most serious cases, on the other hand, may also require pharmacological treatment.
Cefazolin may cause coagulation disorders, therefore, regular checks are necessary in the case of a concomitant anticoagulant therapy.
Cases of positivity to the Coombs test (sometimes false) have been reported during therapy with cefazolin, which can also occur in neonates and women who took the drug before giving birth.
Due to the nephrotoxicity of cefazolin, appropriate renal function checks should be performed in patients with suspected renal disease before starting treatment with the drug. Patients over 50 years of age, patients with a history of kidney disease and patients who also take other nephrotoxic drugs have an increased risk of developing renal toxicity.
Interactions
Probenecid (a drug used in the treatment of gout and hyperuricemia) decreases the rate of elimination of cefazolin and - consequently - increases its plasma concentration.
The concomitant use of cefazolin and nephrotoxic drugs - such as, for example, aminoglycosides, colistin or vancomycin (other antibiotic drugs) - should be avoided.
Some types of antibiotics - such as aminoglycosides, penicillins or chloramphenicol - can have a synergistic effect on the bactericidal activity of cefazolin.
In case of anticoagulant therapy already in progress - during treatment with cefazolin - it may be necessary to adjust the doses of oral anticoagulants administered.
Side effects
Cefazolin can cause various types of side effects, although not all patients experience them. This depends on the different sensitivity that each individual has towards the drug; therefore, it is not said that the undesirable effects are manifested all and with the same intensity in each patient.
The following are the main adverse effects that may occur during cefazolin therapy.
Allergic reactions
Cefazolin can trigger allergic reactions in sensitive individuals. These reactions can occur with symptoms such as:
- Urticaria;
- Itch;
- Skin eruptions;
- Temperature;
- Chills;
- Symptoms similar to those of serum sickness;
- eosinophilia;
- Edema;
- Erythema;
- Angioedema;
- Stevens-Johnson syndrome;
- Toxic epidermal necrolysis;
- Exfoliative dermatitis;
- Anaphylactic reactions, even serious ones.
Blood and lymphatic system disorders
Therapy with cefazolin can cause disorders in the system responsible for the production of blood cells (the hemolymphopoietic system, in fact). Such disturbances can cause:
- Aplastic anemia;
- Hemolytic anemia;
- Plateletopenia (ie the decrease in the number of platelets in the bloodstream), with consequent increased risk of bleeding;
- Leukopenia, ie the reduction in the number of leukocytes in the bloodstream;
- Agranulocytosis, ie the excessive reduction of granulocytes in the bloodstream.
However, these side effects are rare.
Hepatobiliary disorders
Treatment with cefazolin may cause changes in blood concentrations of liver enzymes, increased blood concentration of bilirubin, liver dysfunction and cholestasis.
Gastrointestinal disorders
Treatment with cefazolin can cause nausea, vomiting, diarrhea, abdominal pain, dyspepsia, glossitis and heartburn.
Generally, the effects on the gastrointestinal system are mild and transient. More rarely, on the other hand, they can occur in severe form and may necessitate interruption of therapy.
Renal disorders
Treatment with cefazolin may cause a temporary increase in creatinemia and azotemia. Furthermore - although more rarely - the drug can cause acute renal failure associated with interstitial nephritis.
Nervous system disorders
After intramuscular administration of cefazolin, headache, dizziness and fatigue may occur.
Other side effects
Other side effects that may occur during treatment with cefazolin are:
- Pain and hardening of tissues after intramuscular administration;
- phlebitis;
- Genital or anal itching;
- Vaginitis;
- Moniliasis.
Overdose
The symptoms that can occur in case of overdose with cefazolin are:
- Pain, inflammation and phlebitis at the injection site;
- Sense of failure;
- Headache;
- paresthesia;
- Convulsions, especially in patients with renal insufficiency in which there is an accumulation of medication;
- Alterations in creatinemia, bilirubinemia azotemia and blood levels of liver enzymes;
- thrombocytopenia;
- eosinophilia;
- Leukopenia;
- Prothrombin time extension.
Since there is no antidote against cefazolin hyperdosage, the treatment is only symptomatic and supportive. Hemodialysis, however, can be useful.
In any case, if you suspect you have taken an overdose of medication, you must immediately inform your doctor.
Action mechanism
Cefazolin is a cephalosporin, therefore, it acts by inhibiting the synthesis of peptidoglycan (the bacterial cell wall).
Peptidoglycan is a polymer made up of parallel chains of nitrogenated carbohydrates, joined together by transverse bonds between amino acid residues. These bonds are formed thanks to the action of a particular enzyme, transammidase.
Cefazolin is able to bind to transamidase thus preventing the formation of the aforementioned bonds. In this way, weak areas are generated within the peptidoglycan that lead to the lysis of the bacterial cell and, consequently, to its death.
Mode of Use - Posology
Cefazolin is available for intramuscular administration. It is in the form of a powder and solvent for a solution for injection which must be mixed just before the drug is given.
The dosage of cefazolin must be established by the doctor according to the type and severity of the infection to be treated and according to the patient's health conditions.
In any case, the dose of cefazolin usually given in adults is 1-3 g, to be divided into equal doses that will be administered two or three times a day.
In the treatment of mild or moderate infections in children, the daily dosage of cefazolin is 25-50 mg / kg of body weight, to be divided into 3-4 equal doses that will be administered during the day. In severe infections, the dose of the drug is increased to 100 mg / kg of body weight.
In children under one month of age, cefazolin should not be administered.
A reduction in the dose of cefazolin usually administered is necessary in patients with renal insufficiency.
In the prophylaxis of surgical infections, the dose of cefazolin usually used is 0.5-1 g of drug, to be administered 30 to 60 minutes before surgery.
Pregnancy and breastfeeding
The use of cefazolin by pregnant women should only be done in cases of real need.
Cefazolin is excreted at low concentrations in breast milk, therefore, caution should be used when administering the drug to breastfeeding mothers.
Contraindications
The use of cefazolin is contraindicated in the following cases:
- Known hypersensitivity to cefazolin itself, to other cephalosporins or to other β-lactam antibiotics (such as, for example, penicillins);
- In premature newborns;
- In newborns with less than a month of life.
