Pharmacokinetics, the process that involves drug absorption, distribution, metabolism and excretion (ADME) of antimicrobials, determines pharmacodynamic response, that is, what drugs do to the body. Therefore, of all the pharmacokinetic parameters, elimination half-life (T1/2β), volume of distribution (Vd), maximum plasma concentration (Cmax) and maximum time reached (Tmax) are the most important parameters. Hence, the parameters are unique in determining pharmacokinetic and pharmacodynamic response of antimicrobials. However, it is elimination half-life and minimum inhibitory concentration (MIC) that determine the dosing interval of antimicrobials. The dose range of 2.5 mg/kg for gentamicin passing through 4 mg/kg (ciprofloxacin), 4.2 mg/kg (ampicillin L/A), 5 mg/kg (kanamycin, enrofloxacin, gatifloxacin and norfloxacin), 7 mg/kg (mequindox), 10 mg/kg (amikacin, enrofloxacin, lincomycin, pefloxacin, cefpirome, erythromycin and isoniazid), 20 mg/kg (oxytetracycline) and 30 mg/kg (metronidazole) have elimination half-life of 1.2–67.2 h, Cmax of 0.12–54.4 μg/ml, Tmax of 0.2–24 h, bioavailability of 16–99.8% and plasma protein binding of 0–>80% when administered intramuscularly, intravenously and orally. Human equivalent dose formula could be used to extrapolate human-goat therapeutic doses of antimicrobials. However, some antimicrobials such as sulfadimidine, tulathromycin, oxytetracycline and azithromycin may have high residues in the milk, kidneys, liver, intestines, brain and skeletal muscles and may portend high risk of antimicrobial resistance, hypersensitivity reaction, epidermal necrolysis, Stevens-Johnson syndrome and other adverse drug reactions.
Part of the book: Goats (Capra)
A preponderance of therapeutic and toxic agents that affect erythrocytes is being used in preclinical and clinical settings. Such agents are responsible for wrong diagnosis of a myriad of diseases and poor prognosis of some therapeutic interventions. In view of this, literature search was carried out with a view to investigate morphometry of erythrocytes in various diseased conditions and species of animals. Findings have shown that erythrocyte size, area, and volume vary in different species of animals under different diseased conditions. Environmental factors, toxicants, toxins, therapeutics, and management system, among others, can cause erythrocyte deformation, leading to anemia. Erythrocyte-related diseases include but not limited to sickle cell anemia, malaria, cancer, psychiatric illness, and chronic inflammation. Hence the principal source of our survival is erythrocyte, because it transports oxygen needed for metabolism of cell nutrients.
Part of the book: Erythrocyte