The variety of antibiotics is not due to the fact that most drugs are ineffective, but because the pathogens are extremely diverse, and to destroy them, different active substances are needed. In addition, new strains often prove resistant to already known antibiotics, which leads to the need to develop new drugs.
Cephalexin - antibiotics of class 1 cephalosporins.
Features of the drug
Bacteria produce a variety of substances, in addition to toxins that have a negative effect on the human body, some of these compounds are a problem not so much for the body as for the drug. These, for example, include β-lactamases - enzymes that actively destroy penicillin. They are produced by gram-negative bacteria. As a result, this known and popular antibiotic is powerless before microorganisms.
Cephalosporins have been developed to increase drug resistance to β-lactamases. For now, 5 generations of semi-synthetic derivatives are known that can fight a wider spectrum. The mechanism of action of the whole series is general: suppression of the peptidoglycan layer of the cell wall at the stage of reproduction. At the same time, autolytic enzymes are released, which lead to the death of bacteria.
Cefalexin - Cefalexin, the chemical formula -( 6R, 7R) -7 - [(R) -2-amino-2-phenylacetamido] -3-methyl-8-oxo-5-thia-1-azabicyclo [4.2.0]oct-2-ene-2-carboxylic acid. Compared with all other antibiotics of the series, cephalosporin is characterized by one remarkable feature: it is digested in the gastrointestinal tract, that is, the drug, can be used in the form of tablets and suspensions, intravenous or intramuscular administration is not required. This makes the drug much more popular than its counterparts, since treatment with it does not require mandatory hospitalization.
Photo of Cephalexin
Medicinal forms of
Cephalexin is available in several forms that require oral administration.
- Tablets - with a fraction of monohydrate cephalexin in recalculation on cephalexin 250 mg, coated, are placed in blisters.
- Gelatin capsules - with a casing and lid of light green color with a dose of 250 mg, and with a dark green lid and a greenish-yellow casing at a dose of 500 mg. In the blister packs 8 capsules, are sold in cardboard boxes.
- Granules for the preparation of solutions - 250 mg, the solution is taken inside. The granules have a yellow-orange color, when mixed with water they form a suspension of a characteristic bright orange color, with a fruity smell. Flavors are used different: apple, raspberry, strawberry. Granules are packed in bottles of dark glass with a volume of 100 ml, complete with a measuring spoon.
- Powder for solution - yellow-orange, crystalline, is manufactured with a dosage of 125, 250, 500 mg of substance per 5 ml of powder. Powder is sold in bottles of dark glass with a volume of 100 ml. Since this option is also mainly intended for children who are difficult to swallow tablets, the composition includes flavorings and sucrose, therefore mistakenly is often called a syrup.
Composition of cephalexin
Composition of the drug depends on the form of release. The main active component is monohydrate cephalexin. In the dosage form the content of pure cephalexin is indicated, in fact the amount of monohydrate is higher.
- with the indicated cephalexin content of 250 mg, the amount of monohydrate is 263 mg;
- excipients - monocrystalline cellulose, magnesium stearate;
- gelatinous shell includes gelatin, titanium dioxide, indigo carmine, dye.
Composition of dissolution granules:
- cephalexin in the form of monohydrate in terms of pure substance - 250 mg;
- additional substances - dye, guar gum, sodium saccharinate, sucrose, citric acid anhydride, the corresponding flavor.
In the Russian market capsules and granules are most common for dissolution.
- Capsules with a dosage of 250 mg - packaging, cost from 23 to 40 p.
- Capsules in 500 mg - from 70 to 84 p.
- Granules for dissolution at the rate of 250 mg per 5 ml - from 59 to 70 p.
Pharmacological action of
The medicinal action of cephalexin is based on suppression of the production of membrane protein, which leads to the development of substances capable of destroying bacterial cells. Most of all, the drug is active against gram-positive bacteria, but it can destroy some kinds of gram-negative bacteria.
Cephalexin is a semisynthetic derivative of the class of cephalosporins, which is more resistant to beta-lactamases than penicillins, which allows it to be used more widely, and also when strains of microflora are resistant to penicillins.
The drug is prescribed if the causative agents of the disease are Gram-positive bacteria:
- staphylococci - both producing and not producing penicillas, an enzyme that destroys penicillin;
- sticks of diphtheria.
Also the drug is active against gram-negative bacteria: gonococci, shigella, Escherichia coli, Salmonella. Against anaerobic bacteria, tubercle bacillus, indolpositive strains, the antibiotic is powerless.
- The substance is perfectly absorbed through the walls of the stomach and intestines. Its bioavailability is 90-95%.If the medicine was consumed after a meal, then this somewhat slows the rate of absorption, but does not affect the completeness of absorption.
- When 500 mg of the substance is administered, an therapeutic concentration of 15 mg / ml is reached after an hour. If the excretory system of the patient is normal, then the substance is completely eliminated after 4-6 hours.
- The substance is fairly evenly distributed in all tissues - in bone tissue, in the joint, in bile, in the airways, into the pus. The maximum level is observed in the kidney and liver. Cephalexin enters the breast milk and into amniotic fluid in small amounts. With proteins in the blood binds a little.
- Antibiotic is excreted mainly through the kidneys - glomerular filtration, with urine - 79-89%, and also with bile - 0,5%.Cephalexin is not metabolized and leaves the human body unchanged.
Antibiotics of a wide profile prescribe and at the established diagnosis, that is, precisely knowing, about what originator there is a speech, and at illnesses of an obscure etiology. In the latter case, there is a high probability that the drug will be effective even if against a part of the pathogenic microflora. Cephalexin is classified in this category, as it is effective against both gram-positive and gram-negative bacteria.
The drug is used in the treatment of:
- infections of the respiratory tract - pharyngitis, otitis, tonsillitis, dangerous due to its numerous complications, acute pneumonia and exacerbation of chronic. Also effective antibiotic and with abscess of the lungs and with empyema - accumulation of pus in the cavity;
- infectious diseases of the genitourinary system - cystitis, pyelonephritis, endometritis, prostatitis, as well as gonorrhea and vulvovaginitis;
- infections of the skin and soft tissue - purulent accumulations under the skin - abscesses, necrotic purulent processes, diffuse purulent inflammation, where the lesions spread not only in the skin, but also in the subcutaneous tissue. No less effective is the drug for inflammation of the lymphatic vessels - lymphangitis, and lymph nodes - lymphadenitis;
- infections of bone and joint tissue - osteomyelitis, for example.
Instruction for use
The medicine package includes detailed instructions, but this does not mean that the patient can determine the required dose by himself. The recommended doses are calculated for the patient without deviations in the work of other systems, especially the kidneys and liver. The doctor, knowing about other ailments, calculates the dose taking into account these factors.
- The drug is prescribed for adults and children under 10 years of 250-500 mg. The drug is consumed every 6 hours. Take it you need 30-60 minutes before eating and always drink a glass of water.
- The daily dose of the drug is at least 1-2 g, otherwise it is impossible to maintain a therapeutic curative minimum. In severe infections, up to 4 g per day is prescribed. Complications are quite rare, since the substance is easily excreted in the urine.
- Course duration - 1-2 weeks. If the disease is caused by beta-hemolytic streptococcus A, then the minimum duration of the drug is 10 days.
Capsules are swallowed without chewing or separating the lid from the body. The suspension is pre-prepared. In a standard vial containing 2.5 or 5 g of substance, add 80 ml of distilled water - to the risks on the glass. The resulting suspension will contain 25 or 50 mg in every 5 ml. The suspension is shaken well until a homogeneous mixture is obtained. The suspension is stored for 14 days, before use, the formulation is shaken vigorously.
For infants and toddlers
For small patients under 10 years, the drug is almost always prescribed in the form of a suspension, since the tablets and capsules the children suffer worse. In addition, the suspensions include flavorings and flavoring agents. The dose is determined by taking into account the body weight.
At a weight of less than 40 kg, the daily dose is 25-100 mg / kg body, depending on the severity of the disease. So, with otitis media, the average dose reaches 75 mg / kg and is divided into 4 divided doses - not less. With infections of the skin and soft tissues with pharyngitis, the dose is kept the same, but divided into 2 doses. In severe cases, the daily dose can be increased to 100 mg / kg. The medicine takes 6 times a day.
Age is taken into account according to the following scheme:
- for children under 1 year - with a weight of up to 10 kg, appoint no more than 0.5 grams in knocking;
- for children from 1 to 6 years - 0.5-1 g;
- children under 10 years - 1 g;
- daily dose for children from 10 to 14 years is equal to the average dose for adults - 1-2 grams, but not more.
During pregnancy and feeding
Cephalexin during distribution will fall into both breast milk and amniotic fluid.
- In pregnancy, the drug is prescribed only when absolutely necessary.
- During lactation, if there is a need for a cure for a number of cephalosporins, breastfeeding should be discarded.
- High bioavailability and non-participation in metabolic processes make cephalexin a fairly safe drug. In fact, the limitation is only an excessive sensitivity to beta-lactam antibiotics.
- It is not recommended to use capsules for the treatment of babies under 3 years - this is not a matter of medicine, but only in form.
Side effects of
However, despite the safety of the drug, side effects in cephalexin are very diverse: this is due to the fact that the substance equally well penetrates both into soft tissues and organs.
- With a pronounced allergy, rashes on the skin - hives, erythema, rashes. Quincke's edema is possible, toxic epidermal necrolysis.
- Taking the drug may affect the condition of the digestive tract: vomiting, nausea, diarrhea, anorexia, candidiasis of the intestine. Against the background of existing diseases of the alimentary canal cholestatic jaundice, toxic hepatitis.
- Some patients experienced dizziness, weakness, headache, even hallucinations.
- Cephalexin can provoke candidiasis of the genital organs: vaginitis, vaginal discharge, itching.
- In some cases, changes in the composition of the blood - a decrease in the number of leukocytes or platelets.
- Pain in the joints and tendons is also possible.
- When a drug is prescribed for patients with ARI and CRF or other renal diseases, the dose is determined in view of the amount of creatinine. If the SC is 15-20 ml / min, the daily dose of cephalexin is 1.5 g, less than 5 ml / min - 0.5 g. The drug should be divided into 4 divided doses.
- With sensitivity to carbapenems and penicillins, sensitivity to cephalosporins is also possible.
- When taking antibiotics you need to give up alcohol in any form.
- A false positive reaction is possible when analyzing urine for glucose, as well as a positive direct Coombs reaction. At the survey, this factor should be taken into account.
Overdose of cephalexin causes vomiting, nausea, diarrhea, and convulsions may occur. To compensate for overdose, it is necessary to restore the water-electrolyte balance. To this end, prescribed droppers, forced diuresis, even hemodialysis in severe cases. There is no specific antidote for the substance.
Interaction with other medications
- Cephalexin enhances the effect of nephrotoxic drugs, so it can not be prescribed against a background of treatment involving furosemide, ethacrynic acid, aminoglycosides, otherwise there is a threat of kidney damage.
- The substance enhances the effect of indirect anticoagulants.
- Preparations such as salicylates and indomethacin reduce the rate of excretion of cephalexin.
The drug is actively used in children's therapy and in many respiratory diseases. The reason is not only in a wide range of actions, but also in a convenient form - oral. In addition, the completeness of excretion cephalexin makes it one of the safest antibiotics of the cephalosporin series.
From the patients' point of view, being able to use capsules rather than tolerating injections or droppers is one of the biggest pluses.
Cephalexin is a part of several antibacterial drugs, its structural analogues are
Cephalexin is one of the most popular antibiotics of the cephalosporin series. The reason for this is the effectiveness of the substance, and the possibility of ingestion through the mouth.