Changes

{{unfinished}}

{{unfinished}}

primidone is a close congener of phenobarbital. The drug is a white, crystlalling tastless substance. Orimidone is approved by the FDA for use in the dog for control ov convulsions associated with "true" (rimary" epilepsy, epileptform seizures, virus encephalitis, distemper and "hardpad" disease. It may be the most commonly used antiepileptic agent in veterinary medicine. Although primidone does not appear to have an advantage over phenobarbital therapy in control of seizure disorders, this does not exclude the possibility that a single animal may respond more favourable to one or the other. Primidone is less well tolerated that phenobarbital because of its potential for inducing hepatotoxicity.

Primidone is a barbiturate derivative that is closely related to phenobarbital. It is a colourless, tasteless substance that forms crystals and is metabolised to the active metabolites phenobarbital and phenylethylmalonamide (PEMA). Primidone is widely used in veterinary medicine for the control of epileptiform seizures, but does not appear to have an advantage over phenobarbital despite its greater potential to cause hepatotoxicity. However, it appears that certain individuals may respond more favourably to primidone than phenobarbital.  

Primidone is a barbiturate derivative metabolised to phenobarbital (major) and phenylethylmalonamide, or PEMA (minor). Primidone and its two major metabolites hace anticonvulsant activity, but at leas 85% od the pharmacologic activity is derived from phenobarbital.

Although seizures can be controlled with primidone in dogs, primidone has little advantage over phenobarbital in dogs. Control of seizures ion dogs is correlated with the plasma concentration of phenobarbital rather than primidone. In a comparison between primidone and phenobarbital. there was no significant difference between phenobarbital and primidone with respect to seizure control, and primidone appeared more likely to induce liver injury than phenobarbital. The authors conluded that phenobarbital, rather than primidone, should be the drug of first choice for treatment of canine epilepsy. However, there may be rare cases that respons to primodone when phenobarbital alone has not been effective (1 out f 15). primodone is more expensive than phenobarbital but is not classifies as a controlled drug in the US and therefore does not require the same degree of record keeping.

[[Image:Primidone.jpg|thumb|right|300px|The structure of primidone. Source: Wikimedia Commons; Author: Jesse (2006)]]

 

==Mechanism of Action==

==Mechanism of Action==

Primidone is more toxin in cats and rabis. cats metabolise primidone to phenobarbital to a lesser extent than dogs - less effective, more toxic.

Primidone is more toxin in cats and rabis. cats metabolise primidone to phenobarbital to a lesser extent than dogs - less effective, more toxic.

==Side Effects and Contraindications==

==Side Effects and Contraindications==