Antibiotic Drugs

Antibiotic Resistance

The major mdr efflux pump of Escherichia co//belongs to the RND superfamily and consists of the pump AcrB, the membrane fusion protein AcrA, and the porin TolC. The expression of the genes acrAB is under control of the local repressor AcrR, while tolC and acrAB are additionally regulated by several global transcriptional activators, like MarA induced by salicylate, SoxS derepressed by oxidants, and by Rob directly activated by bile salts.

Order Amoxil (Amoxicillin) Without Prescription 500mg

Amoxicillin: A Broad Spectrum Antibiotic Amoxicillin though originally introduced in the early 1970's for oral use in U.K., has found a gradually regular place as broad spectrum antibacterial to treat the infections of various diseases. Amoxicillin has been found to be more effective against gram positive than gram negative microorganisms and demonstrated greater efficacy to penicillin and penicillin V. Moreover, it has been found comparable to other antibiotics, e.g. ampicillin, azithromycin, clarithromycin, cefuroxime and doxycycline in treatment of various infections / diseases. In the past decade, amoxicillin has been reported to be useful in the management of many indications and is used to treat infections of the middle ear (otitis media) […]

Penicillins: Side Effects

The basic structure of the penicillins consists of a thiazolidine ring, the beta-lactam ring, and a side chain. The beta-lactam ring is essential for antibacterial activity. The side chain determines in large part the antibacterial spectrum and pharmacological properties of a particular penicillin. The rapid emergence of bacteria, particularly Staphylococcus aureus, that produce beta-lactamases (penicillinase) has been partly countered by the development of compounds that resist hydrolysis by beta-lactamases and compounds that are more active than penicillin G against Gram-negative species. This has led to the production of many semisynthetic penicillins, the first of which was meticillin, active against beta-lactamase-producing S. aureus; followed by ampicillin, active against selected Gram-negative bacilli; carbenicillin, […]

Penicillins: Drug-Drug Interactions

Allopurinol The risk of rashes caused by aminopenicillins does not seem to be increased by parallel treatment with allopurinol, as had been suggested before. Aminoglycosides High doses of parenteral penicillin can inactivate aminoglycosides. In patients receiving low doses of aminoglycosides because of reduced renal function this can be clinically important. Parenteral administration of these drugs in neonatal dosages does not seem to produce relevant inactivation, and so temporal separation of the infusions is not required. Piperacillin protected against aminoglycoside nephrotoxicity without reducing its blood concentration; this was possibly a protective effect of co-administered mineral salts. Ciclosporin In a study in lung transplant recipients, ciclosporin nephrotoxicity was potentiated by nafcillin. Methotrexate Beta-lactams […]

Penicillins: Drug Administration

Drug formulations Embolictoxic reactions to penicillin depot formulations were first described in patients with syphilis. The symptoms include fear of death, confusion, acoustic and visual hallucinations, and possibly palpitation, tachycardia, and cyanosis. Generalized seizures or twitching of the limbs have been observed in children and adults. As a rule, the symptoms abate and disappear within several minutes to an hour. They rarely persist for up to 24 hours. If a cardiovascular reaction with a fall in blood pressure occurs simultaneously with typical symptoms, a combination with anaphylactic shock must be considered. Such reactions have been called "pseudo-anaphylactic reactions" or "acute non-allergic reactions", "panic attack syndrome," and "acute psychotic reactions". In several […]

Penicillins: Organs and Systems

Respiratory Bronchospasm may be a consequence of penicillin allergy. Acute severe dyspnea with cyanosis has also been observed without symptoms of bronchial obstruction or pulmonary edema. Specific mechanisms for such cases have yet to be identified. Allergic pneumonitis and transient eosinophilic pulmonary infiltrate (Loeffler's syndrome) are rare. These syndromes have also been observed with penicillin hypersensitivity. In one case, an alveolar allergic reaction, probably due to ampicillin, showed features of an adult respiratory distress syndrome. Nervous system High doses of penicillins, in the order of several million units/day of penicillin G, can produce myoclonic jerks, hyper-reflexia, seizures, or coma. Drowsiness and hallucinations can occur occasionally. Such reactions are due to a […]

Penicillins: Organs and Systems: Immunologic

Type I reactions Anaphylactic shock can occur, even after oral administration of penicillin and skin testing. However, anaphylactic shock is less common after oral than parenteral administration. In one study the incidence of anaphylactic shock was 0.04% of all patients treated with penicillin. It is also low in patients receiving long-term benzathine penicillin (1.2 million units every 4 weeks). Four episodes of anaphylaxis occurred in 0.012% of injections (1.2 reactions to 10 000 injections). Anaphylactic shock resulting in death occurred in 0.002% of all patients treated with penicillin and in 0.003% of those treated with benzathine penicillin. In nearly half of the cases, the course of anaphylactic shock, especially that induced […]

Penicillins: Organs and Systems: Skin

Skin reactions are the commonest adverse effects of therapeutically administered penicillins. Penicillin-contaminated milk or meat can cause itching or generalized skin reactions or even anaphylaxis. Incidence The overall annual incidence of severe erythema multi-forme (toxic epidermal necrolysis and Stevens-Johnson syndrome) is about one case per million, antibiotics being involved in 30-40%. The clinical differentiation between these syndromes can be difficult. Allergic contact dermatitis is usually caused by topical drugs, but is also seen in connection with ingestion, injection, or inhalation. The increased frequency of contact eczema due to cloxacillin and bacampicillin may be because they are intensely irritant and lipophilic. Mechanisms Mechanisms of non-immediate reactions are unclear; but may be immunological […]

Penicillins: Organs and Systems: Liver

Penicillin-induced hepatotoxicity may not be as uncommon as has been thought. There have been three reviews. The first was a comparison of the assessment of drug-induced liver injury obtained by two different methods, the Council for International Organizations of Medical Sciences (CIOMS) scale and the Maria & Victorino (M&V) clinical scale. Three independent experts evaluated 215 cases of hepatotoxicity reported using a structured reporting form. There was absolute agreement between the two scales in 18% of cases, but there was no agreement in cases of fulminant hepatitis or death. The authors concluded that the CIOMS instrument is more likely to lead to a conclusion compatible with the specialist's empirical approach. In […]

Penicillins: Organs and Systems: Hematologic

Since the days when chloramphenicol was more commonly used, it has been recognized that many antimicrobial drug are associated with severe blood dyscrasias, such as aplastic anemia, neutropenia, agranulocytosis, throm-bocytopenia, and hemolytic anemia. Information on this association has come predominantly from case series and hospital surveys (38^. Some evidence can be extracted from population-based studies that have focused on aplastic anemia and agranulocytosis and their association with many drugs, including antimicrobial drugs. The incidence rates of blood dyscrasias in the general population have been estimated in a cohort study with a nested case-control analysis, using data from a General Practice Research Database in Spain. The study population consisted of 822048 patients […]