Which of the following antimicrobial is not given in pregnancy: September 2011
Ans. B: Quinolone Betalactam antibiotics (penicillins and most of the cephalosporins) are safe during pregnancy Erythromycin base is safe but erythromycin estolate should be avoided Quinolones and fluoroquinolones They are chemotherapeutic bactericidal drugs, eradicating bacteria by interfering with DNA replication. Quinolones inhibit the bacterial DNA gyrase or the topoisomerase II enzyme, thereby inhibiting DNA replication and transcription. Quinolones can enter cells easily porins and, therefore, are often used to treat intracellular pathogens such as Legionella pneumophila and Mycoplasma pneumoniae. For many Gram-negative bacteria, DNA gyrase is the target, whereas topoisomerase IV is the target for many Gram-positive bacteria. Theophylline, nonsteroidal anti-inflammatory drugs and coicosteroids enhance the toxicity of fluoroquinolones. Products containing multivalent cations, such as aluminum- or magnesium-containing antacids and products containing calcium, iron, or zinc, invariably result in marked reduction of oral absorption of fluoroquinolones. Many fluoroquinolones, especially ciprofloxacin, inhibit the cytochrome P450 isoform CYP1A2.This inhibition causes an increased level of, for example, antidepressants such as amitriptyline and imipramine, clozapine (an atypical antipsychotic), caffeine, olanzapine (an atypical antipsychotic). Fluoroquinolones are well tolerated, with most side effects being mild to moderate. Some of the serious adverse effects that occur more commonly with fluoroquinolones than with other antibiotic drug classes include CNS and tendon toxicity.Fluoroquinolones are sometimes associated with an QTc interval prolongation and cardiac arrhythmias, convulsions, tendon rupture, torsade de pointes and hypoglycemia. Moxifloxacin carries a higher risk of QTc prolongation Gatifloxacin has been most frequently linked to disturbed blood sugar levels, although all quinolones carry these risks. Some quinolones were withdrawn from the market because of these adverse events (for example, sparfloxacin was associated with phototoxicity and QTc prolongation, thrombocytopenia and nephritis were seen with tosufloxacin, and hepatotoxicity with trovafloxacin).Fluoroquinolones are considered high-risk antibiotics for the development of Clostridium difficile and MRSA infections. The CNS is an impoant target for fluoroquinolone-mediated neurotoxicity. Moxifloxacin came out worst among the quinolones for causing CNS toxicity. Quinolones are contraindicated if a patient has epilepsy, QT prolongation, pre-existing CNS lesions, CNS inflammation or those who have suffered a stroke.There are safety concerns of fluoroquinolone use during pregnancy and, as a result, are contraindicated except for when no other safe alternative antibiotic exists. They are also contraindicated in children due to the risks of damage to the musculoskeletal system.
Penicillin G
Quinolone
Cephalosporin
Erythromycin