Changes

The Food and Drug Administration (FDA) has approved four treatments for use in horses with EPM, but not all of these are commercially available:<ref name="Johnson">Johnson, A.L (2009) Evidence-based review of diagnosis and treatment of ''Sarcocystis neurona'' infection (Equine Protozoal Myeloencephalitis).  ''Proceedings of the Annual Convention of the AAEP'' - Las Vegas, NV, USA, 55:172-176.</ref>

The Food and Drug Administration (FDA) has approved four treatments for use in horses with EPM, but not all of these are commercially available:<ref name="Johnson">Johnson, A.L (2009) Evidence-based review of diagnosis and treatment of ''Sarcocystis neurona'' infection (Equine Protozoal Myeloencephalitis).  ''Proceedings of the Annual Convention of the AAEP'' - Las Vegas, NV, USA, 55:172-176.</ref>

*'''Sulfadiazine and pyrimethamine combination, 'RebalanceTM'''': administered PO daily for a minimum of 90 days. Due to availability and ease of administration, some use an off-label regimen of trimethoprimsulfa tablets with pyrimethamine tablets.  ''Mode of action'': trimethoprim, sulfadiazine, and pyrimethamine all inhibit enzymes of folic acid synthesis.  ''Efficacy'': 61.5% improvement by one clinical grade.(98 in furr)''Potential adverse effects'': bone marrow suppression (mild anaemia, leucopenia, neutropenia, thrombocytopenia), fever, anorexia, depression, acute worsening of ataxiam altered reproductive performance in stallions (19 in IVIS 4), congenital defects(20 in IVIS 4) and abortion.  Folic acid deficiency may also cause gastrointestinal disturbances such as glossitis.(18 in IVIS 4) Blood dyscrazias are typically self-limiting and resolve on withdrawal of treatment. (Furr)

*'''Sulfadiazine and pyrimethamine combination, ('RebalanceTM', Antiprotozoal Oral Suspension, IVX Animal Health)''': administered PO daily for a minimum of 90 days. Due to availability and ease of administration, some use an off-label regimen of trimethoprimsulfa tablets with pyrimethamine tablets.  ''Mode of action'': trimethoprim, sulfadiazine, and pyrimethamine all inhibit enzymes of folic acid synthesis.  ''Efficacy'': 61.5% improvement by one clinical grade.(98 in furr)''Potential adverse effects'': bone marrow suppression (mild anaemia, leucopenia, neutropenia, thrombocytopenia), fever, anorexia, depression, acute worsening of ataxiam altered reproductive performance in stallions (19 in IVIS 4), congenital defects(20 in IVIS 4) and abortion.  Folic acid deficiency may also cause gastrointestinal disturbances such as glossitis.(18 in IVIS 4) Blood dyscrazias are typically self-limiting and resolve on withdrawal of treatment. (Furr)

*'''Ponazuril (Marquis(R), Bayer Animal Health)''': PO daily for 28 days, use in pregnant animals is off-label.  ''Mode of action'': ponazuril is a triazinetrione that targets the “apicoplast” organelle and inhibits the respiratory chain.  ''Efficacy'': well absorbed PO, achieves steady state therapeutic concentration in CSF within 3 days(100 in Furr), clinical response within 10 days, 60% improvement by at least one clinical grade, 8% relapse within 90 days of stopping treatment(91 in Furr).  ''Potential adverse effects'': none in a multi-centre field study<ref name="Johnson">Johnson, A.L (2009) Evidence-based review of diagnosis and treatment of ''Sarcocystis neurona'' infection (Equine Protozoal Myeloencephalitis).  ''Proceedings of the Annual Convention of the AAEP'' - Las Vegas, NV, USA, 55:172-176.</ref>, no systemic toxicity even at high doses.(101 in Furr)However, the manufacturer reports signs that may have been related to treatment including blisters on nose and mouth, skin rash or hives, loose stools, mild colic, and a seizure.<ref name="Johnson">Johnson, A.L (2009) Evidence-based review of diagnosis and treatment of ''Sarcocystis neurona'' infection (Equine Protozoal Myeloencephalitis).  ''Proceedings of the Annual Convention of the AAEP'' - Las Vegas, NV, USA, 55:172-176.</ref>

*'''Ponazuril (Marquis(R), Bayer Animal Health)''': PO daily for 28 days, use in pregnant animals is off-label.  ''Mode of action'': ponazuril is a triazinetrione that targets the “apicoplast” organelle and inhibits the respiratory chain.  ''Efficacy'': well absorbed PO, achieves steady state therapeutic concentration in CSF within 3 days(100 in Furr), clinical response within 10 days, 60% improvement by at least one clinical grade, 8% relapse within 90 days of stopping treatment(91 in Furr).  ''Potential adverse effects'': none in a multi-centre field study<ref name="Johnson">Johnson, A.L (2009) Evidence-based review of diagnosis and treatment of ''Sarcocystis neurona'' infection (Equine Protozoal Myeloencephalitis).  ''Proceedings of the Annual Convention of the AAEP'' - Las Vegas, NV, USA, 55:172-176.</ref>, no systemic toxicity even at high doses.(101 in Furr)However, the manufacturer reports signs that may have been related to treatment including blisters on nose and mouth, skin rash or hives, loose stools, mild colic, and a seizure.<ref name="Johnson">Johnson, A.L (2009) Evidence-based review of diagnosis and treatment of ''Sarcocystis neurona'' infection (Equine Protozoal Myeloencephalitis).  ''Proceedings of the Annual Convention of the AAEP'' - Las Vegas, NV, USA, 55:172-176.</ref>