Antibiotic is a substance that selectively suppresses the activity of microorganisms. Selective effect all a antibiotics means the activity only in against microorganisms without affecting host cells as well as action not on all microorganism but only on some strains. For example, fusidic acid is highly active agains...
Antibiotic is a substance that selectively suppresses the activity of microorganisms. Selective effect all a antibiotics means the activity only in against microorganisms without affecting host cells as well as action not on all microorganism but only on some strains. For example, fusidic acid is highly active against staphylococci, including methicillin-resistant, but has no effect on pneumococci.
The selectivity of antibiotics is closely related to spectrum of activity of antibacterial drugs. However, today the division of antibiotics on drugs with wide and narrow spectrum action is conditional and is subject of much criticism, primarily because of the lack of criteria for such a division. There is an erroneous idea that antibiotics with broad spectrum of activity are more "reliable", more "powerful", but the use of antibiotics with narrow spectrum of activity contributes to a lower development of resistance. However, it does not take into account the acquired resistance, resulting in, for example, tetracyclines, which in the early years of the application were active against most clinically relevant microorganisms and now lost much of their spectrum of activity because of the development of acquired resistance in pneumococci, staphylococci, gonococci, enterobacteria. Cephalosporin of 3rd generation are considered a broad spectrum antibiotics but they do not act on MRSA, many anaerobes, enterococci, Listeria, atypical pathogens, etc.
It is more reasonably to compare antibiotics in context of clinical effectiveness of certain infections as well as clinical evidence of effectiveness obtained in well-controlled (comparative, randomized, prospective) clinical trials which are certainly more important than the conventional type of antibiotic label "broad" or " narrow "spectrum of activity.
Traditionally, antibiotics are divided into natural (proper antibiotics such as penicillin), semisynthetic (modified products of natural molecules, such as amoxicillin or cefazolin) and synthetic (eg, sulfonamides, nitrofurans). Currently, this division has lost actuality because of a number of natural antibiotics produced by synthesis (chloramphenicol), and some medicines called antibiotics (fluoroquinolones), de facto are synthetic compounds.
Antibiotics should be differentiated from antiseptics- chemical compounds which on act on the microorganisms unselectively and are used for the elimination of microorganism in the living tissue. Antibiotics should not be compared with disinfectants intended to elimination of the microorganisms outside the living organism.
Antibiotics represent the largest group of medicines. The number of antibiotics is constantly rises, more than 300 of different antibiotics are currently used in clinical practice. In spite of different effectiveness, spectrum of activity, tolerability all the available antibiotics possess the common features:
First, the uniqueness of antibiotics is that, unlike most other drugs, their target receptor is not in human tissues but in the bacterial cells. Secondly, the activity of antibiotics is not constant, but decreases with time, due to the formation of multidrug resistance (resistance). Antibiotic resistance is an inevitable biological phenomenon and to prevent it is virtually impossible. Third, antibiotic-resistant bacteria pose a danger not only for the patient in whom there were found, but also for many other people, even separated by time and space. That is why the fight against antibiotic resistance has taken a global proportion.
Currently all the antibiotics are divided into several groups and classes.
This division is important in the context of understanding the spectrum of activity, pharmacokinetic characteristics, and the nature of antibiotics side effects. But it is wrong to consider all drugs from one group or class as clinically replaceable. Very often there are a lot of differences in antibacterial effects, spectrum of activity in antibiotics of one group or class. For example, among all cephalosporins of 3rd generation ceftazidine and cefaperazone are the only medications which have clinically significant activity against Pseudomonas aeruginosa. Therefore, even if we get the data in vitro sensitivity of Pseudomonas aeruginosa is sensitive in vitro to cefotaxime or ceftriaxone, these drugs should not be used to treat the infection, as the results of clinical trials which indicate a high failure rate. Another example is the difference in the pharmacokinetic characteristics of antibacterial drugs: cephalosporins I generation (cefazolin) should not be used in the treatment of bacterial meningitis due to poor permeability through the blood brain barrier.
The division of bactericidal and bacteriostatic antibiotics has major practical importance in the treatment of severe infections, especially in patients with disorders of immunity, which must take only bactericidal antibiotics. Among pharmacokinetic characteristics the most important are half-life period and bioavailability (for antibiotics used orally)
Thus, in spite of many commonalities that unite antibacterial drugs, the indication of antibiotics should be based on the results of their effective clinical application or well-controlled clinical trials.
The most common groups of antibiotics include the followings:
Penicillins or beta-lactam antibiotics - penicillins are the first developed antibiotics found in waste products of the microorganisms. Penicillins belongs to wide group of beta-lactam antibiotics. Beta-lactam antibiotics also includes: cephalosporins, carbapenems, monobactams. Beta-lactam antibiotics occupy the leading and important place in the treatment of the majority of infection. Among all penicillins the most widespread is Amoxicillin. Amoxicillin is sometimes used with clavulanic acid which is beta-lactamase inhibitor.
Cephalosporins belong to beta-lactam antibiotics and represent the widest class of antibacterial drugs. Currently there are available 5 generations of cephalosporins. Cephalosporins are used orally or in the form of intravenous or intramuscular injections. Due to their high effectiveness and low toxicity, cephalosporins occupy the leading role in antibacterial therapy among all other antibiotics. The indication of cephalosporin antibiotics depends on their activity, pharmacokinetic characteristics. The mechanism of action of cephalosporins is similar to penicillin.
Carbapenems (imipenem and meropenem) are β-lactams. If to compare to penicillins and cephalosporins, they are more resistant to hydrolysis action of bacterial β-lactamases, including ESBL, and have a broader spectrum of activity. Carbapenems are used in severe infections in various sites, including nosocomial, often as the reserve drugs reserve. In life-threatening infections can be considered as a primary empirical therapy.
Monobactams - among monobactams or monocyclic beta-lactam, only one antibiotic aztreonam is used in clinical practice. It possesses a narrow spectrum of antibacterial activity and is used in the treatment of infections caused by aerobic gram-negative flora.
Aminoglycosides. Aminoglycosides are one of the first antibiotics. The first aminoglycosides was streptomycin which was obtained in 1944. Currently there are 3 generations of aminoglycosides.
Quiolones. Preparations of quinolones class are used in clinical practice since 1960, the mechanism of action fundamentally is different from other antibacterial medications, which guarantee their activity against resistant strains of microorganisms. Class quinolones includes two main groups of drugs, principally differing in structure, activity, pharmacokinetics and indications: non-fluorinated quinolones and fluoroquinolones. Quinolones are classified according to time of introduction of new drugs with enhanced antimicrobial properties. According to the labor classification proposed by R. Quintiliani (1999), quinolones are divided into four generations. One the most well-known antibiotic is Levofloxacin (Levaquin).
Macrolides. Macrolides are a class of antibiotics, the basis of the chemical structure of which is macrocyclic lactone ring. Depending on the number of carbon atoms in the ring , macrolides are divided into 14-membered (erythromycin, roxithromycin, clarithromycin), 15-membered (azithromycin) and 16-membered (Midecamycin, spiramycin, josamycin). The main clinical significance of macrolides is the activity against Gram-positive cocci, and intracellular pathogens (mycoplasma, chlamydia, Campylobacter, Legionella). Macrolides are considered the most safe and well-tolerable antibiotics.
Tetracyclines. Tetracyclines are one of the earliest classes of antibiotics, the first tetracycline were obtained in the late 1940's. Currently because of the large resistance of the microorganism to tetracyclines their use is limited. The greatest clinical significance of tetracyclines (natural and semi-synthetic tetracycline doxycycline) occupy the treatment of chlamydial infections, rickettsial disease, some zoonoses, severe acne.
Lincosamides. Lincosamides include lincomycin which is a natural antibiotic and its semisynthetic analog- clindamycin. Lincosamides have a narrow spectrum of antimicrobial activity, used for the treatment of infections caused by gram-positive cocci (mainly as second-line drugs) and asporogenous anaerobic flora.
Glycopeptides. Glycopeptides include natural antibiotics - vancomycin and teicoplamin. Vancomycin is used in clinical practice since 1958, teicoplanin - since 1980's. Recently, interest in glycopeptides has increased due to the increased frequency of nosocomial infections caused by gram-positive microorganisms. Currently, glycopeptides are the drugs of choice for infections caused by MRSA, MRSE, and enterococci, resistant to ampicillin and aminoglycosides.
Oxazolidinones - is a new group of antibiotics. Currently there is only one antibiotic from this group- linezolid (Zyvox). The medication is used in the treatment of infections caused by the core meaning he has as the drug for the treatment of infections caused by multidrug-resistant gram-positive cocci.
Polymyxins. Polymyxins are one the first natural antibacterial preparations. They were obtained in the beginning of 1940's. The are characterized with a narrow spectrum of antibacterial activity and high toxicity. Polymixin M was used I the treatment of intestinal infections, Currently the use of polymixin is limited.
Sulfonamides. Sulfonamides are first class of antibacterial preparations. In recent years the use of sulfonamides in clinical practice is significantly reduced because of high toxicity and availability of new more effective antibiotics. In long-term use of sulfonamides, most microorganisms develop resistance. Among all sulfonamides the most safe and effective is Biseptol (Bactrim).
Nitroimidazoles. Nitroimidazoles are used to treat protozoa infections. These group include tinidazole, ornidazole, termidazole.
Nitrofurans. Nitrofurans are second class of synthetic antibacterial drugs proposed for broad medical application. They are indicated mainly in the treatment of acute uncomplicated infections, intestinal infections (nifuroxazide) and some protozoal infections - trichomoniasis and Giardiasis.
Where can I purchase antibiotics online?
You can purchase antibiotics online at our online pharmacy. However, you should absolutely b sure that these antibiotics are used for your conditions, that the infection is caused by sensitive to antibiotic microorganism. Do not purchase antibiotics online if you are not sure that the medicines will be effective and safe for our. Do not buy antibiotics online without medical consultation and approval.
How can I purchase antibiotics online?
You can purchase antibiotics online using your Visa card. Do not purchase antibiotics on your own initiative. Antibiotics are used only when the microorganism which caused the infection is determined.
How safe to purchase antibiotics online?
You should purchase antibiotics made by only well known manufacturers. Appropriate use of antibiotics does not cause any significant side effects.
I have infection, can I purchase antibiotics online?
No. At first you should visit your doctor which will prescribe the right medication for your health problems.
Rifaximin is a broad-spectrum antibiotic, it is a semisynthetic derivative of rifamycin SV. It irreversibly binds beta-subunits of bacterial enzyme, DNA-dependent RNA polymerase and thus inhibits the synthesis of RNA and proteins of bacteria.
Generic Zithromax is aт antibiotic used for the treatment of bacterial infections caused by susceptible to azithromycin microorganisms. This medication is a generic form meaning that it contains the same active ingredient as brand drug namely Azithromycin.
Generic Levaquin contains the active ingredient Levofloxacin which is a broad spectrum bactericidal antibiotic of fluroquinolone group. The medication is indicated for the treatment of bacterial infections.
Ciprofloxacin is a bactericidal antibiotic which is also known as Generic Cipro. It is used for treating the infections from the respiratory system, abdominal infections, sexually infections, genital infections and gastrointestinal infections. Ciprofloxacin is an antibiotic from the fluoroquinolone group.
Biaxin is an antibiotic which is having an active ingredient named Clarithromycin which is used to treat the whole respiratory system, especially the lungs. The Biaxin antibiotic is having a good effect against aerobic and anaerobic microorganisms.
Generic Biseptol is a combined antibacterial medication with possesses a broad spectrum of bactericidal activity. Bactericidal effect of the medication is associated with blocking the biosynthesis of folates in microbial cells.
Augmentin tablets or amoxicillin and clavulanate tablets are used for treating the bacterial infection, therefore is an antibiotic. This antibiotic is used in the medicine for fighting with the respiratory infection, dental infection, urinary tract infection,