Antimicrobial drugs prescribing

Table 14.3 Clinical syndromes associated with adverse reactions of commonly prescribed antimicrobial drugs...

Antimicrobial resistance (AMR) is a major, worldwide problem with implications for mortality, morbidity, and consumption of healthcare resources. It is likely that the increase in AMR in recent years is attributable, to a large extent, to overuse of antimicrobial drugs in both humans and animals. Furthermore, it appears that prescribing patterns favouring tower doses of antibiotics for tonger durations contribute more towards AMR. 

These cases of interactions of aminophylline with macro-lide antibiotics illustrate that serious, even fatal, adverse effects can occur when possible interactions are not considered. In both cases, experienced physicians prescribed appropriate antimicrobial drugs, but omitted to consider the possibility of interactions with aminophylline, and failed to reduce the dose of aminophyUme or to measure theophylline concentrations. In the first case the development of tachycardia, hypokalemia, acidosis, vomiting, and convulsions can be explained on the basis of theophylline toxicity caused by ciprofloxacin, while in the second the anxiety, tremor, and cardiac arrests could all have resulted from an interaction of aminophylline and erythromycin. These cases add to an extensive literature that emphasizes the potential for interaction between aminophylline and drugs metabolized by CYP1A2. 

Vrijens B, Urquhart J. Patient adherence to prescribed antimicrobial drug dosing regimens. J Antimicrob Chemother 2005 55 616-627. 

Tetracyclines are produced by various Streptomyces strains and are extensively applied in human and veterinary medicine. They display a broad spectrum of antimicrobial activity in combination with low toxicity and can be applied orally. The most commonly prescribed tetracycline drugs are tetracycline itself and oxytetracycline, an oxygenated derivative, which are directly isolated from fermentation liquors, and doxycycline whose partial synthesis from oxy-... 

Figure 1.4 Percentage of drugs that have been prescribed in the United States for 2003-2005 as a fraction of the top 200 most prescribed drugs. Note that the total of the top 200 most prescribed was 2.1 bilhon, 2.8 biUion, and 2.3 billion for 2003, 2004 and 2005, respectively. AC = Antihypertension/cardiovascular medication, SH = sedatives/antipsychotics, AI = analgesics/anti-inflammatory, AM = antimicrobial, GI = gastrointestinal, AD = antidiabetic, DE = diuretics/electrol3ftes, TH = thyroid drugs. Re = respiratory, CR = contraceptives/ reproductive therapy, BP = biophosphonates and other anti-bone loss, St = steroids. He = hematology, Nu = nutritional, Tr = triptan, AP = antineoplast, AN = anesthetic, and DI = dopaminergics and immunomodulators.

Significant deficiencies in the security and control of samples have been well documented. " " In fact, it has been estimated that just over half of samples actually reach patients. Samples may be used by prescribers and staff, or they may be diverted. Personal use of drug samples by physicians and other healthcare providers raises ethical concerns and is not without risk." Limaye and Paauw described three medical residents who self-prescribed antimicrobials and were subsequently diagnosed with Clostridium difficile infection." Tong and Lien reported self-medication with samples and distribution of samples to nonphysicians by almost 60% of pharmaceutical representatives surveyed at a Canadian family practice office. A contributing factor to some of these issues is that institutional or facility sample policy and procedures are often absent, or compliance is poor. One institution found only 10% compliance when the inventory of samples was compared with the required written documentation. Even after an educational program in which the policy was explained to the house staff, a second audit found only 26% compliance. " Poor compliance with policy and procedure may jeopardize patient safety, as well as put the institution at risk for JCAHO recommendations or Board of Pharmacy penalties. 

Bronchial asthma has been described in a mother who had opened capsules of pancreatic extract, which had been prescribed for her children suffering from cystic fibrosis (Sakula 1977). Piperazine is an anthelmintic drug. Single cases of angioedema, urticaria, exanthema, and erythema multiforme have been reported in Sweden. Suppositories and ointments used for the anal region can cause allergic contact dermatitis. Procaine, benzocaine, cinchocaine, and antimicrobial agents are the most common offenders. We have seen two cases of purpura and one case of urticaria caused by such suppositories. 

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