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Topic:Oral Administration
Oral administration in horses refers to the delivery of medications, supplements, or nutrients via the mouth. This method is commonly used in equine veterinary medicine for its practicality and ease of use. Oral formulations can include powders, pastes, or liquids, which are designed to be palatable and easily ingested by horses. The effectiveness of oral administration depends on factors such as the horse's digestive physiology, the formulation of the product, and the consistency with which it is administered. This page compiles peer-reviewed research studies and scholarly articles that explore the techniques, efficacy, and considerations of oral administration in equine care.
Oral ivermectin paste for the treatment of chorioptic mange in horses. A single blind controlled clinical trial of oral ivermectin paste at a dose rate of 0.1 mg/kg daily for seven days for the treatment of chorioptic mange in horses was carried out. There was a statistically significant reduction in the numbers of mites in the samples taken from the treated horses compared with the untreated horses, but the mites were not eliminated from all the treated animals. Two further groups of horses were treated, one at a dose rate of 0.1 mg/kg daily for 10 days and the other with two doses of 0.2 mg/kg given two weeks apart. There were no statistically significant diffe...
The pharmacokinetics or oral and intravenous allopurinol and intravenous oxypurinol in the horse. The pharmacokinetics of oral and intravenous allopurinol was studied in five horses and compared with intravenous oxypurinol. The plasma concentration vs. time curves, following intravenous administration of 5 mg/kg, were best described by the biexponential equations Cp = 106.58e(-25.14t) + 159.93e(-10.96t) for allopurinol and Cp = 321.09e(-9.72t) + 82.39e(-0.44t) for oxypurinol, with an elimination half-life (t1/2 beta) of 0.09 h and an area under the curve (AUC) of 19.8 mumol.h/L after intravenous administration, while the t1/2 beta and AUC of oxypurinol were 1.09 h and 231 mumol.h/L, respec...
Influence of formulation on the pharmacokinetics and bioavailability of racemic ketoprofen in horses. The bioavailability of S(+) and R(-) ketoprofen (KTP) in six horses was investigated after oral administration of the racemic (rac) mixture. Two oral formulations were studied, an oil-based paste containing micronised rac-KTP and powder from the same source in hard gelatin capsules, each at a dose rate of 2.2 mg/kg. For the oil-based paste two feeding schedules were used; horses were either allowed free access to food or access to food was restricted for 4 h before and 5 h after dosing. The drug in hard gelatin capsules was administered to horses with restricted access to food. After intraveno...
Pharmacokinetics and therapeutic potential for repeated oral doses of trimethoprim/sulphachlorpyridazine in horses. The pharmacokinetic parameters of a powder formulation of trimethoprim/sulphachlorpyridazine were studied in eight healthy horses which received 5 mg/kg trimethoprim and 25 mg/kg sulphachlorpyridazine 12-hourly with concentrate for five days. The intake of the medicated concentrate by the horses was variable during the first two days, but after they became accustomed to the taste the intake by all the horses during the last three days was good. Faecal samples taken before and on the last day of the drug administrations were negative when cultured for salmonella. Compared with the results of a ...
The effects of tonicity, glucose concentration and temperature of an oral rehydration solution on its absorption and elimination. Effects of different tonicities, glucose concentrations and temperatures of an oral rehydration solution (ORS) on its uptake and elimination in resting horses were studied. Fluid and electrolyte deficits similar to those occurring during prolonged exercise were induced by the administration of 1 mg/kg bwt of frusemide i.m., 3 h prior to the ORS. Fluid was administered via nasogastric tube at a volume equivalent to 4% bodyweight, which approximated diuretic induced losses. The uptake of fluid was evaluated by changes in haematocrit (PCV) and plasma total protein concentration (TP). Changes in e...
Dose titration of moxidectin oral gel against gastrointestinal parasites of ponies. Moxidectin was tested as an oral gel formulation during a controlled test performed to evaluate dosages against equine gastrointestinal parasites. Four groups of ten ponies were used. Ponies ranged from 1 to 20 years of age and were naturally infected in southern Louisiana or Mississippi. Fecal exams and fecal cultures were performed on all ponies to determine the strongyle egg counts and the percent distributions of large and small strongyles. Following these determinations, ponies were allocated to replicates of four ponies to provide an even distribution of strongyle infection, age, weight ...
Effect of glucocorticoids on serum osteocalcin concentration in horses. The effects of dexamethasone (0.2 mg/kg of body weight; IV, IM, and PO) and methylprednisolone acetate (120 mg given intra-articularly) on serum osteocalcin and cortisol concentrations were studied in 6 horses. Serum osteocalcin and cortisol concentrations were serially monitored after each treatment. A significant (P < 0.05) decrease in serum osteocalcin and cortisol concentrations was observed from 12 to 24 and 2 to 48 hours, respectively, after IV and IM administrations of dexamethasone. Serum osteocalcin and cortisol concentrations were significantly decreased from 6 to 48 and 3 to 72 h...
Disposition of penicillin G sodium following intravenous and oral administration to Equidae. The present study was designed to determine and compare the plasma disposition and pharmacokinetics of penicillin G sodium following intravenous (i.v.) administration to horses, ponies and donkeys. The plasma disposition and pharmacokinetics of penicillin G was similar in horses, ponies and donkeys (elimination half-lives--39.0, 27.3 and 31.5 min, respectively) and a dosage interval of 6-8 h would be suitable to treat infections caused by susceptible bacteria. Although penicillin G was absorbed rapidly following nasogastric administration, the systemic availability was low (0.12-0.34%), theref...
Kinetic studies and production rate of melatonin in pony mares. The aims of the present study were to determine basic kinetic parameters and the nycthemeral production rate of melatonin in the horse. Seven pony mares were used for the kinetic studies. Five other pony mares were used under long and short days for the production rate studies. Melatonin was administered by intravenous, oral, and intragastric routes at different dose levels. The plasma melatonin clearance was 1.02 +/- 0.31 l.kg-1.h-1, and the volume of distribution was 0.89 +/- 0.53 l/kg for the 0.4 microgram/kg melatonin dose. The systemic availability after oral and intragastric administrati...
Intravenous disposition kinetics, oral and intramuscular bioavailability and urinary excretion of norfloxacin nicotinate in donkeys. An aqueous solution of norfloxacin nicotinate (NFN) was administered to donkeys (Aquus asinus) intravenously (once at 10 mg/kg), intramuscularly and orally (both routes once at 10 and 20 mg/kg, and for 5 days at 20 mg/kg/day). Blood samples were collected at predetermined times after each treatment and urine was sampled after intravenous drug administration. Serum NFN concentrations were determined by microbiological assay. Intravenous injection of NFN over 45-60 s resulted in seizures, profuse sweating and tachycardia. The intravenous half-life (t1/2 beta) was 209 +/- 36 min, the apparent vol...
Pharmacokinetics of trimethoprim/sulphachlorpyridazine in horses after oral, nasogastric and intravenous administration. In the present study, the pharmacokinetic parameters of a trimethoprim/sulphachlorpyridazine preparation following intravenous administration, administration by nasogastric tube and administration with concentrate were determined in the horse. Eight adult horses were dosed at 1 week intervals in a sequentially designed study at a dose of 5 mg/kg trimethoprim (TMP) and 25 mg/kg sulphachlorpyridazine (SCP) on all occasions. Plasma concentrations of both drugs were measured serially for 48 h. Pharmacokinetic parameters of clinical importance (distribution and elimination half-lives, clearance, bi...
Efficacy of moxidectin oral gel against Onchocerca cervicalis microfilariae. During a series of dose-titration experiments designed to evaluate the efficacy of moxidectin oral gel against equine gastrointestinal parasites, infection with Onchocerca cervicalis was diagnosed in 25 of 82 ponies prior to treatment. Microfilariae were identified in full-thickness skin biopsies taken from the ventral midline. Treatment with moxidectin in single doses of 300, 400, or 500 micrograms/kg of body weight was 100% effective in eliminating microfilariae from 20 skin biopsies taken 14 days posttreatment, whereas 5 microfilaria-positive ponies in 2 control groups remained positive fol...
Pharmacokinetics of ciprofloxacin in ponies. The pharmacokinetics of ciprofloxacin was investigated in healthy, mature ponies. Ciprofloxacin was administered intravenously to six ponies at a dose of 5 mg per kg body weight. Seven days later, ciprofloxacin was administered orally to each pony at the same dose. Intravenous ciprofloxacin concentration vs. time data best fit a two-compartment open model with first-order elimination from the central compartment. Mean plasma half-life, based on the terminal phase, was 157.89 min (harmonic mean). Total body clearance of ciprofloxacin was 18.12 +/- 3.99 mL/min/kg. Volume of distribution at stead...
Absorption and dosage of theophylline in the horse after single and repeated administration of a microencapsulated preparation. The kinetics of 2 formulations of theophylline were studied in horses. In an initial cross-over study (Phase I) serum concentration-time curves were determined for granulated and microencapsulated theophylline after a single oral administration (5 mg/kg bwt). In Phase II microencapsulated theophylline was administered at 5 mg/kg bwt/12 h for 10 days at feeding time, as in normal clinical practice. Although no significant differences between the 2 preparations were found with respect to the main kinetic parameters, the microencapsulated form was more evenly and completely absorbed from the dige...
Preliminary study of the metabolism of 17 alpha-methyltestosterone in horses utilizing gas chromatography-mass spectrometric techniques. Little is known about the metabolism of 17 alpha-alkyl anabolic steroids in horses. In this study, the metabolism of 17 alpha-methyltestosterone is investigated by oral administration of a (1 + 1) mixture of the steroid and its deuteriated analogue. Both compounds were synthesized from dehydroisoandrosterone (DHA), using a Grignard reaction followed by an Oppenauer oxidation. Post-administration urine extracts were analysed by gas chromatography--mass spectrometry (GC-MS) using both electron impact (IE) and chemical ionization (CI). Interpretation of the data was facilitated by observation of ...
A comparative study of the pharmacokinetics of intravenous and oral trimethoprim/sulfadiazine formulations in the horse. The biopharmaceutical properties of four fixed trimethoprim/sulfonamide combinations were investigated in the horse. Eight fasted horses were dosed at 1 week intervals in a sequentially designed study with one intravenous (i.v.) and three oral trimethoprim/sulfadiazine (TMP/SDZ) formulations (1, 2 and 3) administered at a dose of 5 mg/kg trimethoprim (TMP) and 25 mg/kg sulfadiazine (SDZ). Plasma concentrations of each compound were monitored for 48 h. Pharmacokinetic parameters (volume of distribution, bioavailability and total body clearance) for TMP and SDZ were calculated and compared. Afte...
Disposition of human drug preparations in the horse. III. Orally administered alclofenac. Concentrations of the non-steroidal anti-inflammatory drug (NSAID) alclofenac were determined by a sensitive high performance liquid chromatographic procedure in plasma and urine of horses following oral administration of a dose of 3 g. In plasma, alclofenac was present in detectable concentrations for 72 h. The plasma disposition in individual horses was best described by a bi-compartmental model with two successive rate constants ka1 = 0.05 +/- 0.06 h-1 and ka2 = 0.06 +/- 0.01 h-1. Alclofenac half-lives t1/2 alpha and t1/2 beta were 1.0 +/- 0.8 h and 6.9 +/- 1.5 h, respectively. Maximal conc...
Effect of drug formulation and feeding on the pharmacokinetics of orally administered quinidine in the horse. Quinidine is the drug of choice for the treatment of cardiac arrhythmias in horses. The plasma concentrations vs. time profiles following oral administration of two formulations of quinidine sulphate, an oral solution and an oral suspension paste, were evaluated in nine horses. They received multiple administrations of the oral solution under fed and non-fed conditions and of the paste under non-fed conditions. A loading dose of 20 mg.kg-1 and a maintenance dose of 10 mg.kg-1 quinidine with dosing interval of 6 h were used. The relative bioavailability of the oral solution under fed conditions...
Plasma disposition of amikacin and interactions with gastrointestinal microflora in Equidae following intravenous and oral administration. Amikacin was detectable (> 0.02 micrograms/ml) in plasma for 12 h in horses and donkeys and for 8 h in ponies following intravenous (i.v.) administration at a dose rate of 6 mg/kg bodyweight. The elimination half-life (harmonic mean) of amikacin was 2.8, 1.6 and 1.9 h in horses, ponies and donkeys, respectively, and the mean body clearance was relatively slow (45.2, 82.4 and 58.0 ml/h.kg, respectively). A suitable dosage interval for the i.v. administration of amikacin sulphate to horses, ponies and donkeys, at a dose rate of 6 mg/kg, would be every 8 h in horses, and every 6 h in ponies an...
Oral bioavailability of pivampicillin in foals at different ages. The plasma disposition of ampicillin after intravenous administration at a dose rate of 15 mg/kg was studied in six healthy, 1-month-old foals. The oral bioavailability of pivampicillin was determined in the same foals at four ages, ranging from 11 days to 4 months. Pivampicillin was administered orally at a dose rate of 19.9 mg/kg, which is equivalent on a molecular basis to 15 mg/kg ampicillin. Ampicillin concentrations in plasma were determined up to 12 hours after administration. After intravenous administration, the mean distribution and elimination half-lives of ampicillin were 0.121 and...
Prolonged presence of isoxsuprine in equine serum after oral administration. 1. Isoxsuprine [1-(4-hydroxyphenyl)-2-(1-methyl-2-phenoxyethylamino)-1- propanol] serum concentrations after single- and multiple-dose administration to horse were investigated using immunoenzymatic ELISA, HPLC-UV and thermospray HPLC-MS methods. 2. Using HPLC-MS, isoxsuprine was detected up to 72 h after a single administration (1.2 mg/kg by gastric probe) and up to 96 h after the end of serial administration (1.2 mg/kg every 12 h for 7 days). 3. ELISA detected the drug up to 96 h after a single dose and up to 6 days after the end of prolonged administration. 4. Isoxsuprine is present in hors...
Trimethoprim/sulfonamide combinations in the horse: a review. The indications for use, side-effects, and pharmacokinetic parameters of trimethoprim, sulfonamides and their combinations in the horse are reviewed. Trimethoprim/sulfonamide (TMPS) combinations are used for the treatment of various diseases caused by gram-positive and gram-negative bacteria, including infections of the respiratory tract, urogenital tract, alimentary tract, skin joints and wounds. TMPS combinations can be administered orally, since absorption from the gastrointestinal tract is relatively good. However, peak serum concentrations can vary significantly between individual horses....
Comparison of oral erythromycin formulations in the horse using pharmacokinetic profiles. The pharmacokinetic properties of four erythromycin formulations were compared in six adult horses after administration of single and multiple oral doses. Formulations of erythromycin administered were estolate and phosphate given 37.5 mg/kg every 12 h and 25 mg/kg every 8 h, and stearate and ethylsuccinate given 25 mg/kg every 8 h. Areas under the curve (AUC) and maximum plasma erythromycin concentrations (Cmax) were equal or greater (P > or = 0.05) following administration of erythromycin phosphate and stearate compared with those values following administration of erythromycin estolate or e...
Preventive administration of bovine colostral immunoglobulins for foal diarrhea with rotavirus. Foal diarrhea due to serotype 3 rotavirus broke out on a foal-raising farm in the years 1987 and 1989. In 1989, all of the foals, regardless of whether or not they suffered from diarrhea, received bovine colostral immunoglobulin (Ig) powder orally for 3 to 5 days during the epidemic. The morbidity of the diarrhea was lower than that observed in 1987, when the Ig powder was not administered to foals. These data suggested that the administration of Ig powder might partially prevent foal diarrhea with rotavirus infection.
Factors affecting drug withholding time estimates in horses. Although all the factors discussed in this article may have an effect on drug withholding time estimates, the factors that have the potential for the greatest effect or that have been found to cause positive tests in the past are 1. Dosage: Increasing the drug dosage will require a longer withholding time. 2. Dosing interval: Narrowing the dosing interval will require a longer withholding time. 3. Administration route: In general, oral administration results in lower peak plasma concentrations but may result in longer excretion in the urine and therefore longer withholding time. 4. Drug intera...
The disposition of suxibuzone in the horse. A high performance liquid chromatographic method is described to determine the anti-inflammatory drug suxibuzone (SXB) and its major metabolites phenylbutazone (PBZ) and oxyphenbutazone (OPBZ) in equine plasma and urine. When suxibuzone (6 mg/kg) was administered intravenously (i.v.) or orally (p.o.) no parent drug was detected in plasma or in urine. The disposition of the metabolite PBZ (i.v.) could be described by a 2 compartment model with a beta half-life varying from 7.40 to 8.35 h. Due to severe side effects the use of i.v. suxibuzone should not be encouraged in the horse. PBZ and OPBZ w...
Disposition, bioavailability and clinical efficacy of orally administered acepromazine in the horse. The pharmacokinetics and pharmacological efficacy of orally (p.o.) administered acepromazine were studied and compared with the intravenous (i.v.) route of administration in a cross-over study using six horses. The oral kinetics of acepromazine can be described by a two-compartment open model with first-order absorption. The drug was rapidly absorbed after p.o. administration with a half-life of 0.84 h, tmax of 0.4 h and Cmax of 59 ng/ml. The elimination was slower after p.o. administration (half-life 6.04 h) than after i.v. injection (half-life 2.6 h). The bioavailability of the orally admini...
Pharmacokinetics of digoxin administered to horses with congestive heart failure. Nine horses with (naturally acquired) congestive heart failure were treated with 2.2 micrograms of digoxin/kg of body weight by the IV route, followed by 11 micrograms/kg administered orally every 12 hours thereafter. Furosemide was administered IV concurrently with IV administered digoxin every 12 hours. Serum concentration of digoxin was measured after the first (IV) and seventh (orally administered) dose. After IV administration, digoxin disposition was described by a 2-compartment model, with a rapid distribution phase (t1/2 alpha = 0.17 hour), followed by a slower elimination phase (beta ...
Dung dispersal and grazing area following treatment of horses with a single dose of ivermectin. Environmental consequences of treating horses with recommended dosages of ivermectin paste were studied in two controlled experiments with 29 horses in Ohio. In 1988, dung dispersal rates were measured by changes in dry weight over time of 48 copromes (300 g) formed from feces taken from four treatment and four control horses 3 days post ivermectin treatment. There was delayed dispersal of copromes from horses treated with ivermectin in June, resulting in significantly heavier ivermectin copromes compared with those of control horses by September. There was no difference in ivermectin or contr...
