Prescription items are
NON-RETURNABLE
and
NON REFUNDABLE
ReBalance Antiprotozoal Oral Suspension
ReBalance® Antiprotozoal Oral Suspension is supplied in 946.4 mL (1 quart) bottles. Each mL of ReBalance® Antiprotozoal Oral Suspension contains 250 mg sulfadiazine (as the sodium salt) and 12.5 mg pyrimethamine.
Indications
ReBalance® Antiprotozoal Oral Suspension is indicated for the treatment of horses with equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona.
Dosage and Administration
ReBalance® Antiprotozoal Oral Suspension is to be administered at a dose of 20 mg/kg sulfadiazine and 1 mg/kg pyrimethamine daily or 4 mL of ReBalance® Antiprotozoal Oral Suspension per 110 lb (50 kg) of body weight once per day. The duration of treatment is dependent upon clinical response, but the usual treatment regimen ranges from 90 to 270 days.
Administer orally by suitable dosing syringe at least one hour prior to feeding with hay or grain. Insert nozzle of syringe through the interdental space and deposit the dose on the back of the tongue by depressing the plunger. Shake well before each use.
Contraindications
The use of ReBalance® Antiprotozoal Oral Suspension is contraindicated in horses with known hypersensitivity to sulfonamide drugs or pyrimethamine.
Warnings
For use in horses only. Do not use in horses intended for human consumption. Not for human use. Keep out of reach of children.
Precautions
Prior to treatment with ReBalance® Antiprotozoal Oral Suspension, EPM should be distinguished from other diseases that may cause ataxia in horses. Injuries or lameness may also complicate the evaluation of an animal with EPM. In most instances, ataxia due to EPM is asymmetrical and affects the front and/or the hind limbs.
Treatment may cause generalized bone marrow suppression, anemia, leukopenia, neutropenia and thrombocytopenia. A complete blood count (CBC) should be performed monthly to monitor horses for development of these conditions. The administration of the drug may need to be discontinued and/or treatments for bone marrow suppression initiated.
Worsened neurologic deficits (treatment crisis) may be observed during a period beginning with the first few days of treatment with ReBalance® Antiprotozoal Oral Suspension and ranging out to 5 weeks. This neurologic deficit exacerbation may be the result of an inflammatory reaction to the dying parasites in the CNS tissue.
The safe use of ReBalance® Antiprotozoal Oral Suspension in horses used for breeding purposes, during pregnancy, or in lactating mares has not been evaluated. The safety of ReBalance® Antiprotozoal Oral Suspension with concomitant therapies in horses has not been evaluated.
Adverse Reactions
Seventy-five horses (37 horses in the 1X group; 38 horses in the 2X group) that were treated with test article for at least 90 days were evaluated for adverse reactions.
Bone marrow suppression:
Anemia: ReBalance® Antiprotozoal Oral Suspension administration caused overall anemia (classification of anemia based on RBC, Hgb, and PCV/HCT values) in 12% of the observations in the 1X group and 21% of the observations in the 2X group. In the 1X group, anemia was noted in 22%, leukopenia in 19%, neutropenia in 5%, and thrombocytopenia in 3% of the cases. In the 2X group, anemia was noted in 58%, leukopenia in 55%, neutropenia in 29% and thrombocytopenia in 5% of the cases. The incidence of bone marrow suppression in the 2X treatment group was two or more times that of the 1X group and the degree of suppression was more serious (mild to severe vs. mild to moderate). Because of these blood dyscrasias, test article was interrupted over four times more often in horses treated at the 2X dosage than those treated at 1X, although both groups were off treatment for about the same amount of time (approximately 20% of the treatment period). In some instances of bone marrow suppression, diet was supplemented with folinic acid.
GI: Anorexia was observed in two horses in the 1X group and one horse in the 2X group. One horse in the 1X group and one horse in the 2X group were observed to be off feed. Observations of anorexia and decreased appetite occurred predominantly during the first 90 days of the treatment period. Observations of anorexia/decreased appetite in two of the above-referenced cases were due to unrelated illnesses. Loose stools were observed in three horses in the 1X group and five in the 2X group. The majority of these observations occurred in the first thirty days of treatment.
Diarrhea was observed in one horse in the 2X group on Day 4 of the study. The appearance of loose stool/diarrhea observations was self-limiting and resolved without treatment or discontinuation of test article. Brief, mild colic was observed in three cases (one in the 1X group and two in the 2X group). Colic was treated conservatively or not at all and resolved without sequelae.
Integument: Urticaria was observed in one horse in the 1X group and two horses in the 2X group. One horse was treated topically, two were untreated. All cases resolved without sequelae.
Treatment crisis (marked worsening of the neurological condition) was reported in one horse in the 1X treatment group.
Depression/lethargy was observed infrequently, occurred during the early part of the study in both groups and was primarily associated with the EPM syndrome. In one case, depression was associated with acute onset of a liver disorder.
Seizure: One horse in the 1X treatment group suffered from seizures. Seizure activity may be associated with CNS damage from EPM.
Storage
Store at controlled room temperature 15° to 30°C (59° to 86°F). Protect from freezing.