Doxycycline belongs to the group of antibiotics included in the category of tetracyclines. The spectrum of action of this semisynthetic drug is quite wide due to the bacteriostatic property. Doxycycline provides a blockage of the multiplication of microbes in the body due to a violation of the synthesis of proteins in the cell of the microorganism. The urgency of the drug is observed in infectious lesions of soft tissues and bones, the genitourinary system, esophagus, respiratory system and skin.
The preparation is produced in yellow capsules in the form of cylinders with semicircular ends. The composition of Doxycycline is represented by a yellow powder with white elements. The weight in the capsule can be compressed and look like a pill. If you use a glass rod to destroy this shape, it will crumble.
What is Doxycycline?
Doxycycline 100 mg acts as an active substance. Among the additional ingredients, there are such as potato starch, lactose monohydrate, as well as calcium stearate. In the manufacture of a hard gelatin capsule, a yellow dye of orange and quinoline shades, sodium lauryl sulfate, titanium dioxide, pure water, as well as a thickener and glycerin are used. The spectrum of the effect of the drug on microbes is very wide.
There is an inhibition of the production of proteins in the microbial cell, the connection between the 30S subunit of the ribosomal membrane and the transport aminoacyl-RNA is disrupted. There is also a bacteriostatic effect. Certain gram-positive microorganisms are very sensitive to Doxycycline. First of all, these are staphylococci, streptococci, listeria, causative agents of anthrax, clostridia, actinomycetes. Also, the drug adversely affects gram-negative microorganisms and intracellular pathogens. With respect to the hemophilic rod and granulocyte erlichiosis, the highest activity of the drug is observed.
What is Doxycycline Used for?
High efficiency is observed in the treatment of acute mycoplasma bronchitis and pneumonia. If concomitant diseases are absent, the drug can be administered to patients under 65 years of age. Speaking of elderly patients, the drug effectively treats urinary infections and acute prostatitis. Resistance to doxycycline is showed by viral and fungal infections, most bacteroids are fraigilis, serrations, proteus mirabilis and Pseudomonas aeruginosa.
Among the indications for the use of doxycycline, infectious pathologies, which were provoked by pathogens that are sensitive to doxycycline, are paramount. This group of pathologies includes the following infections:
- Recurrent typhus of epidemiological type (provocateur – Borrelia of recurrent type);
- Urethritis of non-gonococcal (provoker – T-mycoplasma);
- Rectal, endocervical and urethral infections without complications (provoker – chlamydia);
- Monotherapy is topical for conjunctivitis with discharge, it is possible to combine with local drugs;
- Trachoma is not eliminated in all patients, but treatment in some cases helps;
- Psittacosis (provocateur – Chlamydiapsittaci);
- Respiratory infections (provocative – mycoplasma);
- Tick-borne or spotted fever, typhus, Ku-fever.
Infectious pathologies caused by gram-negative microorganisms are also affected by Doxycycline. Doxycycline is effective in prostatitis, because half an hour later, on average, the necessary concentration of the active substance in the prostate gland is achieved. Such a good interaction with blood proteins demonstrates not every antibiotic. The course of treatment in this case is focused on a standard daily dosage – 2 tablets a day. If there are no complications, a week will be enough.
Among the treatable infections, which are caused by gram-positive microorganisms, anthrax and upper respiratory tract infections. This drug may act as an alternative to penicillin, when the latter is contraindicated. Doxycycline can successfully supplement amebicides in the treatment of acute amoebiasis of the intestine or be used as an auxiliary component in the treatment of acne in severe form. Among the indications is also the prevention of malaria.
Doxycycline Drug Class
Doxycycline belongs to the tetracycline derivative obtained synthetically from oxytetracycline. Doxycycline is a light yellow crystalline powder. Doxycycline monohydrate is very slightly soluble in water, its molecular weight is 462.46. Doxycycline hyclate (hemiethanolate hemihydrate hydrochloride) is soluble in water.
The group of tetracyclines includes a number of antibiotics and their semisynthetic derivatives, related in chemical structure, antimicrobial spectrum and mechanism of action. The basis of their chemical structure is a condensed four-ring system, commonly called “tetracycline“. Tetracyclines are one of the earliest classes of AMP, the first tetracyclines were obtained in the late 40s. Currently, due to the emergence of a large number of microorganisms resistant to tetracyclines and the numerous HPs that are characteristic of these drugs, their use is limited. The greatest clinical importance of tetracyclines (natural tetracycline and semi-synthetic doxycycline) is retained in chlamydial infections, rickettsiosis, some zoonoses, severe acne.
Tetracyclines are broad-spectrum antibiotics. They are active against gram-positive and gram-negative bacteria, spirochetes, leptospira, rickettsia, large viruses (pathogens of trachoma, ornithosis). Individual drugs differ among themselves in the strength of action, the rate of absorption and excretion from the body, metabolism. The mechanism of antibacterial action of tetracyclines is based on their suppression of the biosynthesis of the protein of the microbial cell at the level of the ribosomes. In commonly used doses, tetracyclines act bacteriostatically.
Doxycycline Mechanism of Action
The active substance successfully penetrates almost all tissues and organs of the body, the barrier is only the blood-brain barrier. The medicine can be found in a small amount or can not be detected at all if there are intact cerebral membranes in the cerebrospinal fluid. Determination in breast milk is guaranteed, as in the fetus, because the substance penetrates the barrier of the placenta. Distribution is based on 0.7 l per kilogram of weight.
About 30-60% is excreted by the liver, after 16 hours on average, the half-life of the drug occurs. The probability of cumulation increases with repeated admission. The drug promotes the accumulation in the teeth and bones of complexes with Ca2 +, which do not dissolve.
The following pharmacokinetic properties are also characteristic for this drug:
- Excretion with caloric masses in an amount of 20-60%;
- Exposure to intestinal-hepatic circulation;
- It is secreted by bile;
- Within 72 hours, 40% is excreted by the kidneys;
- The half-life of blood serum occurs in almost the same degree, regardless of the presence of renal pathology;
- The half-life of blood serum does not change after hemodialysis.
Is Doxycycline Safe?
In case of an overdose, the side effects of Doxycycline are neurotoxic reactions, especially if there are liver diseases. This can be increased pressure, cramps and vomiting, nausea and dizziness. Eliminate pathological symptoms can be by abolishing the drug and using activated charcoal to wash the stomach.
Prevention of absorption of the active substance involves the intake of magnesium sulfate and antacids. The lack of effectiveness of peritoneal and hemodialysis explains the fact that there is no special antidote for such cases. If you follow the dosage, the likelihood of side effects of Doxycycline is not high.
Doxycycline is forbidden during pregnancy. It is not allowed to take the medication while the fetus is being carried, otherwise such violations as fatty liver infiltration, suppression of the development of the skeleton and violation of the normal development of the teeth may occur. Similarly, the use of the drug during lactation is prohibited. If therapy is necessary, breastfeeding should be stopped.
Admission of Doxycycline by children: Doctors ambiguously treat the use of the drug in pediatric practice because the active component of the drug is able to slow the longitudinal development of the bones of the skeleton, tooth enamel develops worse, teeth for a long time acquire a gray-brown or yellow tint. However, there are a number of factors in favor of Doxycycline, due to which its use in the treatment of children is reviewed.
- Statistics of cases when adolescents are exposed to chlamydia, is increasing.
- Cases of pneumonia caused by mycoplasma and chlamydia are also being recorded more often.
- Doxycycline is the first choice medicine for the treatment of infections that occur against the background of a tick bite. The incidence of infections of this kind has increased significantly.
- Cosmetic distortion of tooth color is not such a serious side effect as most negative symptoms after taking alternative antibiotics.
- The drug in question is considered the most effective in certain infectious pathologies.
- The use of Doxycycline in pediatric practice has become more common after cases of biological terrorism in Canada and the United States. In some cases, its use in preschool age has become relevant.
Take into account that the simultaneous administration of Doxycycline and alcohol enhances the toxic effect, which is manifested by headaches and dizziness. A small interval between the medications and alcohol will bring the same effect. As to the effectiveness of the drug against the background of alcoholic intoxication, in some cases, there is an increase in the effectiveness of treatment, in others, a decrease.
The results are ambiguous and it is impossible to determine the reaction of the organism in advance. Since both alcohol and Doxycycline decompose in the liver, their simultaneous administration significantly increases the load on this organ, which can cause reactive hepatitis. Consequently, simultaneous reception is strictly prohibited and after the completion of therapy, alcohol can be consumed only after 35 hours.