[Intravenous lysine clonixinate for the treatment of migraine: an open pilot study]

Several oral nonsteroidal anti-inflammatory drugs (NSAID) are effective to treat migraine attacks. Despite its efficacy to treat migraine and other pain, there are a few commercial NSAIDs available for intravenous (i.v.) administration. Lysine clonixinate (LC) is a NSAID derived from nicotinic acid that has been proven effective in various algic syndromes such as renal colic, nerve compression, muscular pain and odontalgias. The aim of this study was to evaluate the efficacy of the i.v. LC in the treatment of severe attacks of migraine. We studied prospectively 19 patients, 17 women and 2 men, ages from 18 to 57 years, with the diagnosis of migraine according to the International Headache Society criteria. The patients were oriented to proceed to the clinic once the headache has started, and were placed under an i.v. infusion of LC and saline in a superficial vein of the forearm, once the intensity reached severe. Evaluating the headache intensity after 30, 60 and 90 minutes, as well as the presence of side effects, we observed that all of the 19 patients were headache free after 90 minutes. Some patients presented mild adverse effects and the vital signs were not significantly affected. We then concluded that the i.v. infusion of the NSAID LC (2-3-chloro-o-toluidin)piridin-3-lysine carboxilate), a derived from the nicotinic acid with a chemical structure that resembles the flufenamic acid, was efficient abolishing a severe migraine attack after 90 minutes in 19 patients. Controlled studies with a double-blind and randomized design, and treating a greater number of patients and attacks are necessary to confirm these initial observations.

[Menstrual prostaglandin and dysmenorrhea: modulation by non-steroidal antiinflammatory drugs]

The analgesic efficacy and tolerance of lysine clonixinate (LC) as well as LC-induced changes in menstrual prostaglandin levels were studied according to a prospective double-blind randomized crossover design, controlled with ibuprofen (I) and placebo (P). Treatment consisted in 4 consecutive phases: in the first phase, patients refrained from taking medication and during the remaining three phases, they received double-blind fixed doses of 1 tablet of lysine clonixinate 125 mg, I 400 mg or P, q.6 h. at random, three days before onset of menses and during 8 days thereafter. Controls were carried out at each menstrual cycle, assessing pain according to a scale from 0 to 4, onset of premenstrual and intramenstrual symptoms, relief of pain and occurrence of side-effects. During menstruation, patients recorded their assessments of pain in a diary and collected the whole menstrual bleeding during the first three days. The intensity of menstrual pain remained unchanged in controls upon admission (3.16) and during the phase with no treatment (3.04), but was significantly reduced with P (2.4), LC (1.79) and I (1.54). Significantly lower pain intensities compared with placebo were seen with active treatment phases. Forty-two percent of patients treated with P reported premenstrual pain which was significantly reduced to 17% with LC and to 12.5% with I. Active treatment phases revealed 21% of asymptomatic patients during premenstrual and menstrual periods and 71% (LC) and 75% (I) of cases with partial relief of pain. Patients' diaries showed significant pain reductions with LC and I, during the 1st and 2nd days compared with P; such differences were gradually reduced to nil by the 4th day. Levels of menstrual PGs changed according to pain intensity reductions from baseline (P: 29%, (NS); LC: 58% and I: 61%; both were statistically significant, p < 0.01).

Drug disposition and dosage determination of once daily administration of gentamicin sulfate in horses after abdominal surgery

OBJECTIVE

To evaluate pharmacokinetics of once daily i.v. administration of gentamicin sulfate to adult horses that had abdominal surgery.

DESIGN

Prospective study.

ANIMALS

28 adult horses that underwent abdominal surgery for colic.

PROCEDURE

14 horses were treated with each dosage of gentamicin (i.e., 6.6 or 4 mg/kg, i.v., q 24 h) and blood samples were collected for pharmacokinetic analysis. Plasma gentamicin concentrations were measured by use of a fluorescence polarization immunoassay. Pharmacokinetic analysis measured the elimination half-life, volume of distribution, and gentamicin total systemic clearance. Treatment outcome, CBC, and serum creatinine concentrations were recorded.

RESULTS

1 horse in the high-dosage group died. All other horses successfully recovered, and did not develop bacterial infection or have evidence of drug toxicosis resulting in renal injury. Mean pharmacokinetic variables for gentamicin administration at a high or low dosage (i.e., 6.6 or 4 mg/kg, i.v., q 24 h) were half-life of 1.47 and 1.61 hours, volume of distribution of 0.17 and 0.17 L/kg, and systemic clearance of 1.27 and 1.2 ml/kg/min, respectively. Mean serum creatinine concentration was 1.74 and 1.71 for the high and low dosages, respectively, and serum creatinine concentration was not correlated with gentamicin clearance.

CONCLUSIONS AND CLINICAL RELEVANCE

Gentamicin administration at a dosage of 4 mg/kg, i.v., every 24 hours, will result in plasma concentrations that are adequate against susceptible bacteria with a minimum inhibitory concentration (MIC) of < or = 2.0 micrograms/ml. Gentamicin administration at a calculated dosage of 6.8 mg/kg, i.v., every 24 hours will result in optimum plasma concentrations against susceptible bacteria with a MIC of < or = 4.0 micrograms/ml.

Effects of flunixin on movement and performance of standardbred trotters on the track

An often discussed and controversial issue is the effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on performance. The purpose of this study was to investigate the effect of the NSAID flunixin on the movement pattern and performance capacity of Standardbred trotters using a standardised track model. Five adult Standardbred horses in training trotted at 2 occasions with a 2 week interval on the same oval dirt track. Before each occasion the horses were either injected with flunixin meglumine (Finadyne) or normal saline solution i.m. 4 h before the performance test (double blind crossover study). The kinematics for 5 consecutive strides were filmed. There was no significant difference in maximal speed between the saline and flunixin treatment sessions. Significant changes in the movement pattern were observed as an effect of the flunixin treatment. The horses maintained the same stride duration while significantly decreasing stance time and increasing swing time in the forelimbs. The horses' range of limb angle decreased significantly. Heart rates were monitored and plasma lactate and flunixin concentrations were measured. No significant differences were found in heart rate and plasma lactate. The results indicate that flunixin had a significant effect on locomotor pattern while it did not effect metabolic response in these horses (considered to represent a normal race track population). The overall effect on performance in racing horses may therefore be related to the anti-inflammatory and analgesic properties of NSAIDs by masking pain and lameness.

Comparison of medical and surgical treatment for impaction of the small colon in horses: 84 cases (1986-1996)

OBJECTIVE

To characterize clinical findings and compare effects of treatment and outcome for horses treated medically or surgically for impaction of the small colon.

DESIGN

Retrospective study.

ANIMALS

84 horses with impaction of the small colon.

PROCEDURE

Medical records were reviewed for history, physical examination findings, laboratory values, treatment, response to treatment, complications, out-come, and necropsy findings.

RESULTS

47 horses were treated medically and 37 horses were treated surgically. Significant differences between groups were not identified for duration of clinical signs, physical examination findings, or laboratory values. Horses treated surgically were hospitalized longer than horses treated medically. Complications recorded during hospitalization included diarrhea, jugular thrombophlebitis, recurrent colic, fever, and laminitis. Salmonella organisms were isolated from 20 horses. Horses treated surgically were more likely to have signs of moderate abdominal pain, gross abdominal distention, and positive results for culture of Salmonella spp than horses treated medically. Follow-up information was available for 27 horses treated medically and 23 horses treated surgically. Twenty-four (72%) and 21 (75%) of the horses, respectively, survived and were being used for their intended purpose at least 1 year after treatment.

CLINICAL IMPLICATIONS

Colitis may be a predisposing factor for impaction of the small colon in horses. Prognosis for horses treated surgically or medically is fair.

Arterially perfused eye model of uveitis

OBJECTIVE

To develop an in vitro model of uveitis based on an ex situ perfused eye to evaluate the anti-inflammatory activity of new pharmacological products.

PROCEDURE

Eyes were removed from more than 60 dogs and 9 horses immediately after euthanasia and perfused with nutrient medium through the lateral long ciliary artery. Perfused eyes produced aqueous humour, and perfusion pressure was adjusted to obtain an intraocular pressure in the physiological range. When the eyes were treated with histamine, a complement C5a analogue peptide and hydrogen peroxide, typical signs of uveitis were produced. These included miosis, vascular leakage, reduced intraocular pressure, reduced flow of perfusate and, in some eyes, conjunctival oedema.

RESULTS

Canine eyes showed a decrease in intraocular pressure and a decrease in perfusate flow rate when challenged with 100 mumol/L hydrogen peroxide. Flunixin meglumine (5 mumol/L), ketoprofen (5 mumol/L), indomethacin (5 mumol/L) as well as a new drug pirfenidone (10 mumol/L) prevented changes in intraocular pressure induced by hydrogen peroxide, but did not significantly moderate the mediator-induced changes in perfusate flow.

CONCLUSIONS

This model is suitable for evaluating potential anti-inflammatory activity of drugs without having to induce uveitis in an experimental animal. The technique is suitable for species that range in size from cats to horses.

Acute phase response in dairy cows with experimentally induced Escherichia coli mastitis

Six Finnish Ayrshire cows were challenged intramammarily with 1500 CFU of Escherichia coli (E. coli) into single udder quarters, and the challenge was repeated into contralateral quarters 3 weeks later. All cows received flunixine meglumine once, and 3 of them were also treated with enrofloxacin. At the 2nd challenge, treatments were changed vice versa. The development of mastitis was followed by monitoring of systemic and local clinical signs, and with serial milk and serum samples. Intramammary challenge with E. coli produced clinical mastitis in all cows, the severity of the disease varying greatly between the animals. No significant changes between the 2 treatment regimens or sequent challenges were found for any of the clinical parameters. The response of each cow followed the same pattern after both challenges; three of the cows became mildly and the other 3 either moderately or severely affected. Two severely affected cows had to be euthanized because of severe mastitis. Serum haptoglobin and amyloid-A concentrations peaked 2-3 days after bacterial challenge. Serum haptoglobin did not correlate with the severity of the disease. Serum amyloid-A rose gradually in the severely affected cows, and significant differences were found between severely versus moderately or mildly affected cows at day 4. Serum tumor necrosis factor alpha concentrations increased only in the severely affected cows. Serum cortisol response was prolonged in the severely diseased animals, and was significantly lower after the second challenge. Serum nitrite/nitrate concentration increased in the severely affected cows. This indicated excess nitric oxide production during acute E. coli mastitis. Strongly decreased milk production, and high bacterial growth in the infected quarters were best predictors for the outcome from acute E. coli mastitis.

[Investigations on the treatment of cerebrospinal nematode infections in goats]

In 17 goats the therapeutical outcome of cerebrospinal nematodiasis, a parasitic infection in the central nervous system with the nematode Elaphostrongylus cervi, is described. The diagnosis was made on the basis of physical findings and cerebrospinal fluid eosinophilia. The therapy was based on the administration of a non-steroidal antiinflammatory drug (flunixin meglumine) and two anthelmintics (fenbendazol, ivermectin) for five days. The response to therapy was documented immediately and 30 days after therapy and by owners report up to 30 months. Eleven goats (64.7%) showed an improvement of the neurological signs directly after therapy. Three had a complete recovery. Signs of a light and middle ataxie were still present in 6 and 2 goats, respectively. Six recumbent goats (35.3%) had to be euthanasied because of a non-therapeutical response. This study has shown a clinical impression of successful use of flunixin meglumine, fenbendazole and ivermectin in goats with light to middle neurological signs. The goats could accommodate the remaining ataxia without showing a reduced production. Goats with high neurological deficits could not be successful treated based on the high degree of the neurological damage.

The laryngeal mask airway in experimental pig anaesthesia

The pig is used as a large animal model in many research projects. Standard practice for airway maintenance under general anaesthesia is using endotracheal (ET) intubation after intravenous induction to a near surgical plane. This is a technically demanding skill, requiring the assistance of an experienced technician. A technique is required which simplifies pig anaesthesia. This study examined the feasibility and potential advantages of using the laryngeal mask airway (LMA) in 10 pigs during laparotomy under spontaneous breathing anaesthesia. The results show that the LMA can be inserted rapidly, with minimal time for airway control by researchers relatively inexperienced in anaesthesia and is associated with few complications. By removing the need for intravenous induction, an entire step in the anaesthetic process is removed. The LMA designed for humans fits well in the pig hypopharynx; all pigs could be manually ventilated with no detectable gas leak. Although the pigs in this study were spontaneously breathing it is proposed that the LMA should be further investigated in studies of artificially ventilated pigs.

Pharmacokinetic studies of flunixin meglumine and phenylbutazone in plasma, exudate and transudate in sheep

Flunixin meglumine (FM, 1.1 mg/kg) and phenylbutazone (PBZ, 4.4 mg/kg) were administered intravenously (i.v.) as a single dose to eight sheep prepared with subcutaneous (s.c.) tissue-cages in which an acute inflammatory reaction was stimulated with carrageenan. Pharmacokinetics of FM, PBZ and its active metabolite oxyphenbutazone (OPBZ) in plasma, exudate and transudate were investigated. Plasma kinetics showed that FM had an elimination half-life (t1/2beta) of 2.48 +/- 0.12 h and an area under the concentration - time curve (AUC) of 30.61 +/- 3.41 Lg/mL x h. Elimination of PBZ from plasma was slow (t1/2beta = 17.92 +/- 1.74 h, AUC = 968.04 +/- microg/mL x h). Both FM and PBZ distributed well into exudate and transudate although penetration was slow, indicated by maximal drug concentration (Cmax) for FM of 1.82 +/- 0.22 microg/mL at 5.50 +/- 0.73 h (exudate) and 1.58 +/- 0.30 microg/mL at 8.00 h (transudate), and Cmax for PBZ of 22.32 +/- 1.29 microg/mL at 9.50 +/- 0.73 h (exudate) and 22.07 +/- 1.57 microg/mL at 11.50 +/- 1.92 h (transudate), and a high mean tissue-cage fluids:plasma AUClast ratio obtained in the FM and PBZ groups (80-98%). These values are higher than previous reports in horses and calves using the same or higher dose rates. Elimination of FM and PBZ from exudate and transudate was slower than from plasma. Consequently the drug concentrations in plasma were initially higher and subsequently lower than in exudate and transudate.

Efficacy and tolerance of lysine clonixinate versus paracetamol/codeine following inguinal hernioplasty

In this study lysine clonixinate, a nonsteroidal antiinflammatory agent with selective inhibition of cyclooxygenase-2 and 5-lipooxygenase in in vitro and in vivo pharmacodynamic studies, was evaluated in a prospective, randomized, double-blind, double-dummy clinical study versus paracetamol/codeine, in 151 patients with pain following inguinal hernioplasty. Patients were treated with one 125 mg tablet of lysine clonixinate or paracetamol/codeine (500 mg + 30 mg) administered at fixed doses every 4 h during 2 days. Controls were carried out 1, 2 and 4 h after the first intake of day 1 and day 2. Each control included assessment of pain at rest, when coughing, sitting and upon moderate pressure. Both treatment groups (lysine clonixinate, 77 patients and paracetamol/codeine, 74 patients) were comparable in terms of demographic and baseline pain intensities. Spontaneous pain was reduced significantly in both treatment groups from the 1st-h control. The following values were recorded in the lysine clonixinate group during day 1: baseline: 6.86 +/- 1.24; 1st h: 4.49 +/- 1.77; 2nd h: 2.96 +/- 1.74; 4th h: 2.23 +/- 1.51. The following values for the same group during day 2 were: predose: 1.70 +/- 1.64; 1st h: 1.16 +/- 1.17; 2nd h: 0.78 +/- 1.06; 4th h: 0.63 +/- 1.05. The paracetamol/codeine group revealed the following values: day 1: baseline: 6.72 +/- 1.22; 1st h: 4.57 +/- 1.72; 2nd h: 2.97 +/- 1.68; 4th h: 2.47 +/- 1.68 and day 2: predose: 2.02 +/- 1.57; 1st h: 1.32 +/- 1.23; 2nd h: 0.82 +/- 0.99; 4th h: 0.66 +/- 0.89. Reduction of pain induced by coughing, sitting and pressure showed similar behavior patterns. No significant differences between both treatment groups were encountered in terms of analgesic efficacy. Incidence of adverse effects was significantly higher in the paracetamol/codeine group (X2: p < 0.05): 11 out of 74 patients; three patients had to discontinue treatment. In the lysine clonixinate group four out of 77 patients showed side effects but these did not require treatment discontinuation.

Streptococcal peritonitis in a young dromedary camel

A male dromedary camel was presented for a primary Streptococcal zooepidemicus septic peritonitis. An underlying gross lesion was not identified during abdominal exploratory surgery. The camel responded to peritoneal lavage, peritoneal drainage and systemic antibiotic therapy. Thrombophlebitis of the left jugular vein was diagnosed 14 days after surgery. The camel died of an unknown cause 24 days after surgery.

Lysine clonixinate vs. paracetamol/codeine in postepisiotomy pain

This study was conducted to compare the analgesic action of Lysine Clonixinate (LC) vs Paracetamol/Codeine association (PC) in the treatment of postepisiotomy pain in primiparae women: 131 primiparous patients with moderate-to-severe postepisiotomy pain were enrolled in a double blind dummy design study and randomly allocated to either treatment with fixed doses of LC 125 mg or Paracetamol 500 mg+Codeine 30 mg 6 qh during 24 hours. Intensity of spontaneous pain and pain on walking was assessed according to a visual analog scale (VAS) and patient's assessment before receiving treatment and after 1, 2, 6 and 24 hours. Intensity of spontaneous pain was reduced in 24 hours from 4.28 +/- 2.11 to 1.73 +/- 1.46 (P < 0.0001) in the LC group and from 4.78 +/- 2.08 to 1.90 +/- 1.72 in the PC-treated group (p < 0.0001); with no significant differences between treatments. 54% of the patients treated with LC and 55% of those receiving PC showed onset of analgesic action 30 minutes following dose administration. Patient's final global assessment revealed that 95% of LC-treated patients and 96% of the PC group showed total or partial pain relief during the first treatment day. No sleep disturbances were seen during the night in 75% of patients. Only one patient receiving LC showed nausea not requiring treatment discontinuation. It is concluded that both treatments are equally effective to relieve moderate-to-severe postepisiotomy pain.

Ivermectin toxicosis in a zebra

A 3-mo-old zebra was accidentally given 2.08 mg ivermectin/kg bw orally. Ataxia, blindness and depression developed within a few hours and resolved with symptomatic and supportive treatment by the fifth day post-exposure. These effects were similar to those reported in horses, including the temporary blindness.

[Analgesic-antispasmodic effect and safety of lysine clonixinate and L-hyoscinbutylbromide in the treatment of dysmenorrhea]

The purpose of this longitudinal open but not comparative study was to confirm the safety and efficacy of Lysine clonixinate (125 mg) and hyoscinbutylbromide (10 mg) capsules, during a period of observation of there menstrual cycles on 30 women with uterine dysfunction due to primary or secondary dysmenorrhea. The time of evolution for primary dysmenorrhea was of 4.46 years, and for secondary was of 1.77 years. Some associated manifestations of dysmenorrhea were: nausea (92%), vomit (92%), general pain (82.1%), abdominal pain (85.7%) and headache (46.4%). Regarding to the menstrual pain intensity, at first was highly severe in 10.7% severe in 42.9%, and moderate in 46.4%. At the end of the study, only 1 of 28 patients showed menstrual pain of moderate intensity. Only three adverse effects of light intensity were found without needing treatment, related to the manifestations of gastralgia and sleepiness. The association of a spasmolytic analgesic (Lysine clonixinate and hyoscinbutylbromide bromide) on the treatment for primary or secondary dysmenorrhea, reduces and prevents the menstrual pain (colic) as well as the associated manifestations with few spasmolytic association is efficacy and safety.

Effect of pentoxifylline, flunixin meglumine, and their combination on a model of endotoxemia in horses

OBJECTIVE

To compare effects of a single dose of pentoxifylline (PTX), flunixin meglumine (FM), and their combination (FM/PTX) in a model of equine endotoxemia.

ANIMALS

24 healthy horses, aged 2 to 15 years.

PROCEDURE

4 groups (n = 6/group) received 30 ng of Escherichia coli O55:B5 endotoxin/kg of body weight, i.v., over 30 minutes, and 1 of the following preparations 15 minutes before and 8 hours after endotoxin infusion: FM, 1.1 mg/kg; PTX, 8 mg/kg; FM/PTX, 1.1 mg of FM and 8 mg of PTX/kg; and saline solution bolus (ENDO). Clinical and hematologic variables were measured over 24 hours.

RESULTS

Compared with ENDO, FM given before endotoxin significantly reduced TxB2, and 6-keto-PGF1 concentrations, pulse, rectal temperature, and attitude score. Pentoxifylline given before endotoxin resulted in significantly higher 6-keto-PGF1 concentration at 1.5 hours and significantly lower PAI-1 activity at 12 hours. Tumor necrosis factor and IL-6 activities in horses given PTX alone were not significantly different from values in those given the saline bolus. FM/PTX induced effects similar to those of FM alone on endotoxin-induced changes in temperature and TxB2 concentration, and 6-keto-PGF1 concentration was significantly lower than that in horses of the ENDO group at 1 hour. In horses of the FM group, 6-keto-PGF1 concentration was significantly lower than that in horses of the ENDO group, from 0.5 hour to 2 hours. Horses of the FM and FM/PTX groups had significantly higher IL-6 activity at 1.5 and 2 hours than did horses of the PTX and ENDO groups; those of the FM and FM/PTX groups had significantly lower WBC count than did those of the PTX and ENDO groups.

CONCLUSIONS

FM/PTX may help offset deleterious hemodynamic effects of endotoxin more effectively than does either FM or PTX alone.

Comparison of carprofen and flunixin meglumine as adjunctive therapy in bovine respiratory disease

In an open, controlled, multi-centre clinical field trial, seven 'naturally occurring' outbreaks of acute febrile (rectal temperature > or = 39.5 degrees C) respiratory disease in housed calves were treated with a single antimicrobial agent, and either the non-steroidal anti-inflammatory drug (NSAID) carprofen (n = 95) or flunixin meglumine (n = 92) on an alternate basis. Carprofen was administered as a single subcutaneous injection at a mean dosage of 1.4 mg kg-1 (range 1.2 to 1.9 mg kg-1) body weight on the first day and flunixin meglumine by intravenous injection at a mean dosage of 2.0 mg kg-1 (range 1.2 to 2.6 mg kg-1) body weight on the first 3 consecutive days. All calves were examined clinically immediately prior to initial treatment and on three occasions up to 1 week after the end of treatment. There were no statically significant differences between NSAID groups in reduction of clinical parameters between examinations, or in overall efficacy. This trial demonstrated that a single dose of carprofen was equally effective as three daily doses of flunixin meglumine as adjunctive therapy to antimicrobial treatment in acute respiratory disease in calves.

Infectious temporomandibular joint disease in the horse: computed tomographic diagnosis and treatment of two cases

Diagnostic imaging and treatment of unilateral destructive temporomandibular joint disease in two horses is described and discussed. Computed tomography appeared to be the best imaging technique for these lesions. The disease can be followed by functional recovery after the infection has resolved.

Combination of medical and surgical therapy for pleuropneumonia in a horse

Medical management was unable to prevent the development of an extrapulmonary abscess in a 10-year-old Thoroughbred gelding with anaerobic pleuropneumonia. Intercostal thoracostomy achieved drainage of the abscess. Resolution of the abscess and subsequent bronchopleural fistulas was monitored by ultrasonography and video-endoscopy. The horse returned to training 4 mo after discharge.

Use of carprofen for the treatment of pain and inflammation in dogs

Most studies of nonsteroidal anti-inflammatory drugs (NSAID) do not demonstrate appreciable differences in efficacy. As awareness of the adverse effects associated with NSAID use increases, safety is becoming the primary concern among physicians when selecting NSAID for use by their human patients. However, veterinarians may be less aware of the safety concerns associated with NSAID use. A wide range of NSAID is used to treat human beings with osteoarthrits; however, it is imperative to remember that dogs are especially sensitive to these drugs, and reports of serious, and occasionally fatal, complications are numerous. Carprofen is a propionic acid-derived NSAID that has anti-inflammatory, analgesic, and antipyretic activity. In animals, carprofen is as potent as indomethacina and more potent than aspirin or phenlbutazone, but carprofen appears to be safer than most other NSAID.

Epizootic of equine protozoal myeloencephalitis on a farm

OBJECTIVE

To determine the clinical findings, course of treatment, and long-term outcome of horses on a farm in central Kentucky during an epizootic of equine protozoal myeloencephalitis (EPM).

DESIGN

Cohort study.

ANIMALS

21 horses on a farm in central Kentucky, 12 of which developed clinical signs of EPM.

PROCEDURE

Horses on the farm were serially examined for signs of neurologic disease and serum and CSF antibodies to Sarcocystis neurona. Horses were considered to have EPM if they had neurologic signs and positive test results for antibodies to S neurona in CSF. Blood values were monitored for evidence of abnormalities resulting from long-term pyrimethamine and trimethoprim-sulfamethoxazole administration Physical, neurologic, and fetal necropsy examinations were performed as needed. Horses were treated for EPM until they had negative test results for CSF antibodies to S neurona.

RESULTS

Of 21 horses on the farm, 12 had EPM over the course of 6 months. The duration of treatment ranged from 45 to 211 days, excluding 1 horse that persistently had CSF antibodies to S neurona. Adverse effects from pyrimethamine and trimethoprim-sulfamethoxazole administration included transient fever, anorexia, and depression (n = 2); acute worsening of ataxia (2); mild anemia (4); and abortions (3).

CLINICAL IMPLICATIONS

EPM may develop as an epizootic. In the horses of this report subtle clinical signs that were originally considered unimportant ultimately progressed to obvious neurologic signs. Adverse effects associated with EPM treatment included worsening of neurologic signs, anemia, abortion, and leukopenic and febrile episodes.