Antibiotics after surgery

In clinical practice, antibiotics are used after surgery to avoid purulent postoperative complications associated with bacterial infection of the surgical site.

Patients wonder whether antibiotics are needed after surgery? Doctors give an affirmative answer and argue that, in addition to the local infection that many patients undergoing surgery have, the presence of opportunistic infections (which develop against the background of decreased immunity) should be taken into account, as well as nosocomial infections (i.e. hospital-acquired), which quickly attack the body weakened by surgery.

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Indications for the use of antibiotics after surgery

Courses of antibiotics after surgery are mandatory for extensive interventions for penetrating injuries or purulent inflammation of the abdominal and thoracic organs.

Antibiotics after abdominal surgery – for pyogenic abscesses and necrosis of any internal organs, peritonitis, intestinal perforation, etc. – are designed to prevent the development of bacteremia and the most dangerous postoperative complications – abdominal or general sepsis.

During any operation, it is difficult to prevent microbial contamination - the penetration of nosocomial infections: Staphylococcus aureus, streptococci, Pseudomonas aeruginosa, Enterobacter, Pseudomonas, etc. Indications for the use of antibiotics after surgery are the elimination of existing foci of inflammation and a decrease in the likelihood of secondary infection during surgical interventions on the gastrointestinal tract (especially on the cecum, colon and rectum); on the gallbladder, bile duct and liver; on the kidneys (during nephrostomy or nephrectomy); on the pelvic organs (during surgical treatment of urological and gynecological diseases); on the lungs (in thoracic surgery); on the heart (in cardiac surgery); in vascular and neurosurgery.

In this case, antibiotics after surgery in case of purulent-inflammatory complications should be prescribed taking into account the place of their development, the intensity of the inflammatory process, the specificity of the infectious agent and its resistance (stability) to certain antibacterial agents. Doctors give preference to the most effective and fast-acting drugs with a wide spectrum of antimicrobial activity, with a lower risk of side effects and easier perception by the operated patients.

In surgical and intensive care units, antibiotics are released in the form of systemic use by parenteral administration - powders for the preparation of injection solutions (antibiotics of the cephalosporin and carbapenem group) or a ready-made solution in ampoules. It is possible to prescribe tablets, and for children - in the form of suspensions (if the patient's condition allows and the degree of inflammatory processes is insignificant). And how many days antibiotics are injected after surgery, as a rule, does not depend on its type or localization: the type of bacteria and the condition of the patients are important. The drugs of this pharmacological group have a strictly regulated and biochemically substantiated duration of use (at least six to seven days), however, in the presence of extensive purulent inflammation, bacteremia or sepsis, courses of antibiotics after surgery can be longer and more intensive - with a combination of several drugs, the synergistic effect of which will provide targeted and effective antibacterial therapy.

Pharmacodynamics

Like all cephalosporin antibiotics, Cefotaxime, Cefazolin and Ceftriaxone act bactericidally due to their ability to penetrate the cells of aerobic and anaerobic microorganisms and modify their protein enzymes (transpeptidases), which leads to inhibition of the synthesis of bacterial cell wall peptide and prevents their cell division.

The pharmacodynamics of the aminoglycoside Amikacin differs from the mechanism of action of cephalosporins: drugs of this group do not penetrate into bacterial cells, but disrupt protein synthesis in ribosomes, irreversibly binding to protein enzymes of the 30S subunit of the cellular ribosome. That is, cell mitosis becomes impossible, and the bacteria die.

Due to the smaller size of the molecules, the antibiotic of the carbapenem group, Merapenem, penetrates bacterial cells faster and also disrupts the synthesis of proteins necessary for the reproduction of microbes. In addition, carbapenems can suppress the synthesis of toxins by gram-negative bacteria, and this provides an additional therapeutic effect of Merapenem and all antibiotics of this group.

The drug Amoxiclav is a combination of the penicillin agent amoxicillin and clavulanic acid. Amoxicillin acts by reducing the enzymatic activity of bacterial transpeptidases and blocking the formation of their cell membranes. And clavulanic acid (in the form of potassium clavulanate), entering microbial cells, neutralizes their beta-lactamases - enzymes with which microorganisms protect themselves from antibacterial agents.

Pharmacokinetics

From 25 to 40% of the administered Cefotaxime binds to blood plasma proteins, penetrates into the tissues of internal organs and fluids and has a bactericidal effect for 12 hours. Two-thirds of the drug is excreted unchanged through the kidneys and intestines (with a half-life of 60-90 minutes). A third of the drug is transformed in the liver into active metabolites that have an antibacterial effect.

The pharmacokinetics of Cefazolin are identical to Cefotaxime, but the half-life is approximately two hours.

The bioavailability of Ceftriaxone, even with intramuscular administration, is almost 100%, and binding to plasma proteins is up to 95% (with a maximum concentration 90 minutes after injection). Ceftriaxone also penetrates all tissues of the body, from where it is excreted with urine and bile: the half-life is 6-9 hours, in old age - twice as much, and in children - up to 7-8 days. Poor kidney function contributes to the accumulation of the drug.

Meropenem also has high bioavailability; it enters the tissues and fluids of the body, with no more than 2% of the drug binding to plasma proteins. 12 hours after administration, up to 70% of this drug is excreted unchanged by the kidneys, the rest is metabolized in the liver.

Aminoglycoside antibiotics after surgery (Amikacin) are concentrated in fluids and in the intercellular space of the tissues of the lungs, liver and kidneys, the meninges (with craniocerebral localization of infectious inflammation); binding to plasma proteins does not exceed 11%. The maximum content in the blood is noted approximately 90 minutes after injection into the muscle. In the body, Amikacin is not subject to decomposition and is excreted by the kidneys (the half-life is approximately two hours).

The active ingredients of Amoxicillin (Augmentin) – amoxicillin and clavulanic acid – penetrate into tissues and fluids; bind to plasma proteins (20-30%); are maximally concentrated in the secretion of the maxillary sinus, middle ear cavity, pleural cavity and lungs, cerebrospinal fluid, uterus and ovaries. Amoxicillin is excreted from the body with urine, practically not undergoing metabolism; clavulanic acid is transformed in the liver and excreted by the kidneys, intestines and through the respiratory tract.

Names of antibiotics after surgery

The list below includes the names of antibiotics after surgery that are used more often than other drugs of this class in today's domestic surgery. These are drugs such as:

• cephalosporin antibiotics: Cefotaxime (other trade names: Claforan, Intrataxim, Kefotex, Clafotaxime, Talcef, Cefosin), Cefazolin (Cefamezin, Kefzol), Ceftriaxone (Longacef, Rocephin), etc.;
• antibiotics of the aminoglycoside group: Amikacin (other trade names: Amikacin sulfate, Amicil, Amitrex, Amikozid, Likacin, Fartsiklin);
• antibiotics of the carbapenem group Meropenem (synonyms: Mepenem, Mepenam, Meronem, Mesonex Meronoxol, Meropenabol, Propinem, Sayronem);
• drugs of the penicillin group: Amoxiclav (other trade names: Amoxicillin, potentiated with clavulanate, Augmentin, Amoxil, Clavocin, A-Clav-Pharmex, Flemoklav).

All these drugs are beta-lactam antibiotics. It is no coincidence that cephalosporin antibiotics after surgery were named first: their high activity against most gram-negative and many gram-positive bacteria allows them to successfully combat infectious inflammations after surgical interventions and hospital infections with minimal negative side effects.

Method of administration and dosage of antibiotics after surgery

The most appropriate way to use antibiotics after surgery is by injection.

Thus, Cefotaxime, Cefazolin, Ceftriaxone and other cephalosporin antibiotics are administered intramuscularly or by jet and drip into a vein. A single dose for adults is determined by the severity of the condition: 0.25-0.5 g every 8 hours, 1 g every 12 hours, 2 g every 6-8 hours. It is noted that the dose of antibiotics after surgery needs to be adjusted downward after the patient's condition improves.

Amikacin is injected intramuscularly (for 7-10 days) or administered intravenously by jet stream (for 3-7 days); the daily dose of the drug is calculated based on body weight (10-15 mg per kilogram) and is divided into two or three injections.

The antibiotic Meropenem is prescribed to be administered intravenously by bolus or by long-term intravenous infusions. The dosage varies depending on the severity of the condition after surgery: 0.5 g three times a day (for inflammatory foci in the lungs, genitourinary system, soft tissues and skin); 1-2 g - for bacterial contamination, including sepsis. The dosage for pediatric patients is calculated based on their weight (30-60 mg per kg).

Amoxiclav in the form of an injection solution is used intravenously (slowly): the dose for adults and children over 12 years old is 1.2 g (three times a day); children over 3 months and up to 12 years old - 30 mg per kilogram of weight. The standard course of treatment after surgery is two weeks.

Children under 6 years of age can be given Amoxiclav in suspension form: in a daily dose of 40 mg per kilogram of body weight (in three doses); children under three months - 30 mg per kilogram. Any changes in dosage are made by a doctor, assessing the patient's condition.

Use of antibiotics after surgery during pregnancy

According to official instructions, Cefotaxime, Cefazolin and Amoxiclav may be used during pregnancy and lactation only for strict indications (doctors must assess the balance between the benefits for the woman and the risk of negative effects of the drug on the fetus).

Ceftriaxone is not used in the first three months of pregnancy, and when using this drug during lactation, breastfeeding is temporarily suspended, since the antibiotic enters the mother's milk.

During pregnancy, the use of antibiotics Meropenem and Amikacin is contraindicated.

Contraindications for use

Contraindications to the use of Cefotaxime include hypersensitivity to cephalosporins and penicillin antibiotics, bleeding, and a history of inflammation of the small and large intestines (enterocolitis).

Cefazolin and Ceftriaxone are also not used in patients with hypersensitivity; Ceftriaxone is contraindicated in renal or hepatic insufficiency.

Amikacin has such contraindications as inflammation of the auditory nerve (neuritis), hyperuremia, liver and kidney failure, neonatal period of children. Meropenem should not be used in children under three months of age.

Amoxiclav is contraindicated for use in the treatment of patients with hypersensitivity to clavulanic acid, amoxicillin and all penicillins, as well as in hepatitis and mechanical jaundice resulting from cholestasis.

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Side effects of antibiotics after surgery

The use of almost all antibacterial drugs can be accompanied by nausea, vomiting, diarrhea, abdominal pain and disruption of the intestinal microflora (dysbacteriosis).

In addition, the side effects of antibiotics after surgery - when using Cefotaxime and Cefazolin - can be expressed in allergic reactions, headaches, a decrease in the level of leukocytes and platelets in the blood, inflammation of the tissues and walls of the veins at the injection site.

Ceftriaxone, in addition to the side effects already listed, can cause inflammation of the renal pelvis and the development of a fungal infection (candidiasis). The use of Amikacin can damage the kidneys and impair hearing.

Amoxiclav (Augmentin) may cause hematuria, and Meropenem side effects include seizures.

Overdose

Overdose of Cefotaxime, Cefazolin, Ceftriaxone and Meropenem is expressed in the increase of side effects of these drugs. Overdose of Cefotaxime is neutralized with desensitizing agents (antihistamines). If the dose of Cefazolin and Ceftriaxone is exceeded, accelerated hemodialysis can be used.

Overdose of Amikacin may cause dizziness, nausea and vomiting, hearing loss, dysuria, thirst, impaired coordination of movements and breathing. Intensive antitoxic therapy with hemodialysis and artificial ventilation may be required.

As noted in the instructions, an overdose of Amoxiclav (Augmentin) may manifest itself in the form of dizziness, sleep disorders, mental overexcitation and convulsions. Symptomatic treatment is prescribed.

Interactions with other drugs

The following interactions with other drugs have been noted for the indicated antibacterial agents used after surgery.

Cephalosporin antibiotics (Cefotaxime, Cefazolin, Ceftriaxone, etc.) should not be used simultaneously with diuretics and aminoglycoside antibiotics due to increased negative effects on the kidneys. NSAIDs should also be avoided to avoid increasing the risk of bleeding.

Amikacin is incompatible with such antibiotics as kanamycin, neomycin and monomycin. When Amikacin is used simultaneously with Levomycetin, tetracyclines and sulfanilamide agents, the effect of all drugs is significantly enhanced. Anesthetics in combination with aminoglycosides can lead to respiratory arrest.

Storage conditions and shelf life

After surgery, antibiotics should be stored in a place protected from light, at a temperature no higher than +24-25°C.

The shelf life of the drugs Cefotaxime, Ceftriaxone, Amikacin, Meropenem, Amoxiclav is 2 years, Cefazolin – 3 years.