Epilepsy drugs

Question 1

Chemical categories

Answer 1

1. Barbiturates
   - Phenobarbital
   - Pentobarbital
   - Primidone
2. Benzodiazepines
   - Diazepam, Midazolam
   - Clonazepam
   - Carbamazepin
3. Others:
   - Phenytoin
   - Valproic acid
   - Gabapentin
   - Felbamate
   - Topiramate
   - Lamotrigine
   - Bromide salts
   - Vigabatrin

Question 2

Drugs for treatment of Status Epilepticus

Answer 2

• Diazepam
• Phenobarbital (Pentobarbital)
• Propofol

Question 3

Drugs for prevention of seizures

Answer 3

• Phenobarbital (Luminal, Sevenal)
• Phenytoin
• Valproic acid
• Bromide salts
• Clonadepam
• Clorazepate
• Felbamate
• Gabapentin
• Levetiracetam
• Primidone
• Topiramate
• Vigabatrin

Question 4

Effects of Phenobarbital

Answer 4

• Sedation
• Drowsiness
• Ataxia
• Polyphagia, polyuria,

Question 5

Which is the drug of choice for controlling status epilepticus for dogs and cats, and the anticonvulsant of choice of horses?

Answer 5

Diazepam, Midazolam

Question 6

Types and effects of benzidiazepines

Answer 6

1. Clonazepam:
   •Better oral absorption and decr. tolerance development
   •Diarrhoea can develop, increase dosage from s.i.d. → t.i.d. or a period of several days to counteract
2. Clorazepate
3. Carbamazepine
   •Similar characteristics to Phenytoin but with less side effects.
   •Good for psychomotor epilepsy.

Question 7

Administration of Primidone

Answer 7

-Do not adm. w. barbiturates!

Question 8

Administration of Bromide salts (Na/K)

Answer 8

Alone or with phenobarbital

Question 9

Effects of Bromide salts (Na/K)

Answer 9

• Long ½ life
• Side effects: sedations, pruritic (itchy) skin lesions, polydipsia, polyuria, ataxia, stupor (lack of cognitive function)

Question 10

Effects of Phenytoin

Answer 10

• Cardiac anti-dysrhythmic activity
• Anticonvulsant
• Absorption and metabolism variable
• Short elimination ½ life in dog (difficult to achieve therapeutic levels), extremely long in cats (toxicity!)

Question 11

Effects of other antiepileptic drugs:

1. Na Valproate
2. Gabapentin
3. Felbamate

Answer 11

1.	Na Valproate
•Excellent oral absorption in dogs but short ½ life. 
•Used in patients where other drugs have failed, mainly in combination
2.	Gabapentin
•	Food has no effect on absorption. 
•	Side effects uncommon, non-sedating. 
•	Mainly used in combination.
3.	Felbamate
•	Well tolerated in dogs (not humans)

Question 12

Contraindicated drugs for epileptics

Answer 12

•Tranquilizers
•Others drugs capable of inducing seizures:
→	Morphine/opioid derivatives
→	Ketamine
→	Alpha 2 agonists
→	Methylxanthines
→	Metoclopramide
→	Fluorinated quinolones
→	Chloramphenicol