Long acting Barbiturates
90-60% effectiveness (combination or substitution)
Slow (10-20 min) onset of actions: not good for seizure treatment
Long hl 37-73h
Dose:
IV dog: 2.5-3 mg/kg BID initial dose - Cpss in 2-3 weeks, optimal plasma concentration 1h before administration
IV cats: half this
Good oral absorption
For parenteral maintenance in status epilepticus: 2-6 mg/kg IV, IM
For oral maintenance in status epilepticus: 2-3 mg/kg PO every 12h
Indication:
- Subhypnotic dose: Long term treatment of epilepsy (Anticonvulsives)
- Primidone is a last resort treatment for long term epilepsy (Anticonvulsives)
- Sedative (SedatoHypnotics)
- Behavior Modifiers: For travelling
Side effects:
- Sedation, ataxia
- Polyphagia
- PU/PD
- Elevated liver enzymes
- Autoinduction (not in cats) of CYP450 > need to increase dose of other liver metabolized drugs such as Levetiracetam and Benzodiazepines (BDZ) = Drug interaction
- Strong ROS prod in the liver: need to take Antioxidant Hepatoprotectives such as Silymarin
- Idiosyncratic reactions:
- Hepatotoxicity (Not in cats)
- Pancreatitis
- Necrolytic dermatitis
Contraindications:
Liver failure patients