Therapeutic drug monitoring in veterinary medicine

This article presents some of the more important principles and concepts of therapeutic drug monitoring and when it might be an appropriate diagnostic procedure in veterinary medicine.     

抗生素的安全使用

在兽医临床中使用抗生素类药物应注意以下几点：（1）严格掌握适应症,弄清致病微生物的种类及动物对药物的敏感性。动物对一些抗生素也有过敏反应,也应当进行皮试,有条件时应做药敏试验,为了减少损失,对一些敏感性强的名种畜,宜皮试为好。这样既可对症下药,又可节省用药,减少开支;（2）注意用量及疗程,应根据药物作用和对动物的药动学特点,制定给药方案与剂量。     

Antimicrobial use in the treatment of calf diarrhea

Calves with diarrhea often have small intestinal overgrowth with Escherichia coli bacteria, regardless of the inciting cause for the diarrhea, and 30% of systemically ill calves with diarrhea have bacteremia, predominantly because of E coli. Antimicrobial treatment of diarrheic calves should therefore be focused against E coli in the small intestine and blood, the 2 sites of infection. Fecal bacterial culture and antimicrobial susceptibility testing is not recommended in calves with diarrhea because fecal bacterial populations do not accurately reflect small intestinal or blood bacterial populations and because the break points for susceptibility test results have not been validated. Antimicrobial efficacy is therefore best evaluated by the clinical response of a number of calves to treatment, with calves randomly assigned to treatment groups. Amoxicillin, chlortetracycline, neomycin, oxytetracycline, streptomycin, sulfachloropyridazine, sulfamethazine, and tetracycline administered PO are currently labeled in the United States for the treatment of calf diarrhea. On the basis of published evidence for the oral administration of these antimicrobial agents, only amoxicillin can be recommended for the treatment of diarrhea. Dosage recommendations are amoxicillin trihydrate (10 mg/kg PO q12h) or amoxicillin trihydrate-clavulanate potassium (12.5 mg combined drug/kg PO q12h) for at least 3 days; the latter constitutes extra-label drug use. Parenteral administration of broad-spectrum beta-lactam antimicrobials--ceftiofur (2.2 mg/kg IM or SC q12h) and amoxicillin or ampicillin (10 mg/kg IM q12h)--or potentiated sulfonamides (25 mg/kg IV or IM q24h) is recommended for treating calves with diarrhea and systemic illness; both constitute extra-label drug use. In calves with diarrhea and no systemic illness (normal appetite for milk, no fever), it is recommended that the health of the calf be monitored and that oral or parenteral antimicrobials not be administered.     

兽药的合理使用

科学、高效、安全地使用兽药,不但能及时预防和治疗动物疾病,提高养殖效益,而且对控制和减少药物残留、提高动物产品质量具有重要意义。     

兽用合成抗菌药的安全使用

抗菌药物在保障畜禽健康、促进畜禽生长、提高经济效益方面起了积极的作用。然而长期使用,具有危害性。首先,导致细菌产生耐药性;其次,敏感菌得到了控制,不敏感菌或耐药菌乘机大量繁殖,产生新的致病菌,     

Sulphonamides: updates on use in veterinary medicine

Sulphonamides are the oldest class of antimicrobials and are still the drug of choice for many diseases in veterinary patients. They are classified based on their pharmacokinetics and pharmacodynamics. This article presents an overview of various sulphonamides in each classification, the mechanisms of bacterial resistance, and the effectiveness and maintenance of skin concentrations. Clinical indications, routes and frequency of administration, duration of therapy, compliance factors, cost, adverse drug reactions and drug interactions are described. Controversial topics such as current usage and recommendations for sulphonamide use in dermatology are also discussed.     

Computer use and applications in veterinary medicine.

An 8-year-old neutered male cat with a history of intermittent collapse and dyspnea was evaluated. Hypertrophic cardiomyopathy was diagnosed on the basis of findings from physical examination, radiography, and echocardiography. Cardiac arrhythmias were not recorded during routine electrocardiography. Continuous ambulatory electrocardiography documented severe ventricular arrhythmias (ventricular premature complexes, ventricular bigeminy, and paroxysmal ventricular tachycardia). Continuous ambulatory electrocardiography can detect intermittent and potentially life-threatening cardiac arrhythmias.     

Antimicrobial drug use and resistance in dogs

Fifteen years (1984-1998) of records from a Veterinary Teaching Hospital were analyzed to determine whether antimicrobial drug resistance in coagulase-positive Staphylococcus spp. (S. aureus, S. intermedius) isolated from clinical infections in dogs has increased, and whether there has been a change in the species of bacteria isolated from urinary tract infections in dogs. In coagulase-positive Staphylococcus spp., a complex pattern showing both increases and decreases of resistance to different classes of antimicrobial drugs was observed, reflecting the changing use of different antimicrobial drug classes in the hospital over a similar period (1990-1999). In canine urinary tract infections identified from 1984 to 1998, an increase in the incidence of multiresistant Enterococcus spp. was apparent, with marginal increases also in incidence in Enterobacter spp. and in Pseudomonas aeruginosa, both of which, like Enterococcus spp., are innately antimicrobial-resistant bacteria. A survey of directors of veterinary teaching hospitals in Canada and the United States identified only 3 hospitals that had any policy on use of "last resort" antimicrobial drugs (amikacin, imipenem, vancomycin). Evidence is briefly reviewed that owners may be at risk when dogs are treated with antimicrobial drugs, as well as evidence that some resistant bacteria may be acquired by dogs as a result of antimicrobial drug use in agriculture. Based in part on gaps in our knowledge, recommendations are made on prudent use of antimicrobial drugs in companion animals, as well as on the need to develop science-based infection control programs in veterinary hospitals.     

Population pharmacokinetics in veterinary medicine: Potential use for therapeutic drug monitoring and prediction of tissue residues

Population pharmacokinetics can be defined as a study of the basic features of drug disposition in a population, accounting for the influence of diverse pathophysiological factors on pharmacokinetics, and explicitly estimating the magnitude of the interindividual and intraindividual variability. It is used to identify subpopulations of individuals that may present with differences in drug kinetics or in kinetic/dynamic responses. Rooted in procedures used in engineering systems, population pharmacokinetics methods were conceived as a means to determine the pharmacokinetic profile in populations in which a sparse number of samples were obtained per individual, such as those in late stage human clinical trials. This is the situation commonly encountered in all aspects of veterinary medicine. The exploratory nature of this technique allows one to probe relationships between clinical factors (such as age, gender, renal function, etc.) and drug disposition and/or effect. Similarly, the utilization of these techniques in the clinical research phases of drug development optimize the determination of efficacy and safety of drugs. Given the observational nature of most studies published so far, statistical methods to validate the population models are necessary. Simulation studies may be conducted to explore data collection designs that maximize information yield with a minimum expenditure of resources. The breadth of this approach has allowed population studies to be more commonly employed in all areas of drug therapy and clinical research. Finally, in veterinary medicine, there is an additional field in which population studies are potentially ideally suited: the application of this methodology to the study of tissue drug depletion and drug residues in production animals, and the establishment of withdrawal times tailored to the clinical or production conditions of populations or individuals. Such application would provide a major step toward assuring a safe food supply under a wide variety of dose and off-label clinical uses. Population pharmacokinetics is an ideal method for generating data in support of the implementation of flexible labelling policies and extralabel drug use recently approved under AMDUCA (Animal Medicinal Drug Use Clarification Act. 21 CFR Part 530).