Anticonvulsants Flashcards

(77 cards)

1
Q

Anticonvulsants

A

Anti-seizure, Anti-epileptic Drug used to treat seizures **Control signs not cause of problem**

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Seizure (convulsion)

A

Clinical manifestation of abnormal activity in the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Epilepsy

A

Multiple seizures during long period of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Status epilepticus

A

Seizure lasting 5+mins, or two or more discrete seizures without full recovery of consciousness between seizures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Anticonvulsant Causes of seizures

A

Primary Secondary Reactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Primary type causes of seizure

A

Idiopathic epilepsy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Secondary type causes of seizure

A

Distemper Head/Injury Encephalitis CNS tumors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Reactive type causes of seizure

A

Fever/ Heatstroke Poisoning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Anticonvulsant Mechanism of action

A

Limit either the initialization or spread of seizure focus *PICTURE*

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Anticonvulsant- Status Epilepticus At-Home treatment

A

Diazepam - Emergency! 1-2 mg/kg per rectum (teat cannula, rubber catheter) up to 3x within a 24 hour period -Suppositories, gel formations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Anticonvulsant- Status Epilepticus In-hospital management

A

ABC - airway, breathing, circulation STOP SEIZURES Treat cause Prevent further brain damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Anticonvulsant- Status Epilepticus Stop Seizure! Treatment Name the drugs

A

Diazepam (IV, Rectal, CRI) Lorazepam Midazolam Clonazepam Clorazepate Phenobarbital General anesthesia (last resort)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Anticonvulsant- Status Epilepticus - Treatment Diazepam - IV

A

5-10 mg to effect ~= 0.5 mg/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Anticonvulsant- Status Epilepticus - Treatment Diazepam - Rectal

A

1-2 mg/kg if no IV access

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Anticonvulsant- Status Epilepticus - Treatment Diazepam - CRI

A

0.5 mg/kg/h - absorption into plastics -If seizures recur after diazepam boluses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Anticonvulsant- Status Epilepticus - Treatment Phenobarbital

A

10-20 mg/kg IV increments to effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Anticonvulsant Prevention When to start treatment?

A

More than one seizure per month Seizure within one week of head injury Brain lesion identified

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Anticonvulsant Treatment

A

Drugs given long term Quality of life Reduce frequency & severity while avoiding serious side effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Anticonvulsant - Long term treatment stats

A

Effective in about 33% Some control in 33% Ineffective in the rest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Anticonvulsant Benzodiazepines Used for long term treatment?

A

No! not for long-term

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Anticonvulsant -Benzodiazepines Duration of action?

A

Short, frequent administration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Anticonvulsant -Benzodiazepines Cross tolerance?

A

No further use in status epilepticus Enzyme induction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Anticonvulsant -Benzodiazepines Oral diazepam in cats

A

Leads to fatal liver necrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Anticonvulsant - Client education

A

Client compliance Goals of treatment Potential side effects Missed dose Supply of medication Data log

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Anticonvulsant - Drug choice criteria
Efficacy Safety Price Pharmacological information Clinical experience Single drug vs. combination
26
Anticonvulsant - Drug dose
Recommended doses are only a guide Lower end for new patients, (adjust upward as needed) Higher end of "loading dose" for frequent & severe seizures (then adjust downward)
27
Anticonvulsant - PK considerations
Loading Dose PK change over time (phenobarbital)
28
Anticonvulsant - PK considerations - Loading Dose
For drugs eliminated slowly (brombide & phenobarbital) No time for tolerance to sedative side effects
29
Anticonvulsant - Drug list
Peanut Butter Love Zone Feels Very Good Phenobarbital Brombide Levetiracetam Zonisamide Felbamate Valproate Gabapentin
30
Anticonvulsant Phenobarbital Length of action
Long-acting barbiturate
31
Anticonvulsant Phenobarbital Receptor activity
Potentiates GABAa receptor activity
32
Anticonvulsant Phenobarbital Drug of choice in what species
Dog & Cat
33
Anticonvulsant Phenobarbital Loading dose administration
Loading Dose can be given IV
34
Anticonvulsant Phenobarbital Target concentration
Target concentration = 15-40ug/ml
35
Anticonvulsant Phenobarbital Side Effects
Cytochrome p450 induction Sedation Hyperexcitability Restlessness Polyuria/Polydipsia/Polyphagia
36
Anticonvulsant Phenobarbital Cytochrome p450 induction
Initial T1/2 beta in dogs ~100hrs T 1/2 beta after induction ~24hrs
37
Anticonvulsant Phenobarbital Toxicosis
Hepatotoxicity Anorexia Sedation Ataxia Icterus Ascites
38
Anticonvulsant Brombide
Unknown mechanism of action
39
Anticonvulsant Brombide Ways it is used
Initial therapy or as add-on to phenobarbital
40
Anticonvulsant Brombide T 1/2
21-24 days!
41
Anticonvulsant Brombide Excretion
Filtered & reabsorbed in kidneys High chloride intake increases elimination
42
Anticonvulsant Brombide Loading dose
Use NaBr if given IV KBr - congestive heart failure NaBr- hypoadrenocorticism
43
Anticonvulsant Brombide Side effects
Vomiting Sedation Ataxia Weakness Polyuria/ Polydipsia/ Polyphagia Pancreatitis
44
Anticonvulsant Brombide Toxicosis
Blindness Ataxia Paresis Altered behavior Dysphagia Megaesophagus
45
Anticonvulsant Brombide Toxicosis protocol
Reduce/stop Br Diuresis (IV fluids, furosemide) Do not use in cats! Pneumonitis!
46
What anticonvulsant drug should not be used in cats?
Brombide! Pneumonitis!
47
Anticonvulsant Levetiracetam
Unknown mechanism of actio Synaptic vesicle protein GABA- & Glycine-gated currents Voltage-dependent K+ currents
48
Anticonvulsant Levetiracetam Half life
T 1/2= 3-4 hours (Dogs) = 3 hrs (Cats)
49
Anticonvulsant Levetiracetam Uses/ Combinations
Monotherapy or as add-on with phenobarbital
50
Anticonvulsant Levetiracetam Side effects
Sedation & decreased appetite (uncommon)
51
Anticonvulsant Zonisamide
Unknown mechanism Blocks voltage-gated sodium channels Blocks T-type calcium channels Potentiates GABAa receptors Enhances Glu uptake Reduces GABA uptake
52
Anticonvulsant Zonisamide Uses/Combination
Monotherapy or as add-on to phenobarbital
53
Anticonvulsant Zonisamide Half-life
T 1/2 beta = 15 hr in dogs = 35 h in cats
54
Anticonvulsant Zonisamide Side effects
Cytochrome P450 induction Sedation, ataxia, vomiting Metabolic acidosis
55
Anticonvulsant Gabapentin Mechanism of action
Blocks N-type voltage-gated calcium channels (a2 gamma subunit)
56
Anticonvulsant Gabapentin Metabolism/Excretion
Excreted in urine Only partially metabolized in liver to N-methyl-gabapentin
57
Anticonvulsant Gabapentin Half-life
T 1/2b = 2-4 hours in dogs
58
Anticonvulsant Gabapentin Uses/ Combination
As add-on with phenobarbital & /or bromide
59
Anticonvulsant Gabapentin Effect
Mild sedation & ataxia
60
Anticonvulsant Gabapentin Oral solution
Oral solution contains xylitol (toxic to dogs)
61
Which drug's oral solution is toxic to dogs? What is the toxic chemical?
Gabapentin oral solution Contains xylitol
62
Anticonvulsant Felbamate Mechanism of action
Potentiates GABAa receptors Blocks voltage-dependent Na+ channels Blocks NMDA receptors
63
Anticonvulsant Felbamate Metabolism/Excretion
Dogs: 30% metabolized in liver Rest excreted unchanged in urine
64
Anticonvulsant Felbamate Half-life
T 1/2b = 5-6 hrs in dogs
65
Anticonvulsant Felbamate Uses/ combinations
Monotherapy or Add-on with phenobarbital
66
Anticonvulsant Felbamate Effects
Nervousness Mild thrombocytopenia Leucopenia Hepatic disease
67
Anticonvulsant Valproate Mechanism of action
Blocks voltage-gated Ca channels Potentiates GABAa receptors Reduces T-type calcium currents
68
Anticonvulsant Valproate Half-life
T 1/2B = 1.5-3 hr (dogs) = 8.5 hr (cats)
69
Anticonvulsant Valproate Uses/Combination
As add-on with phenobarbital
70
Anticonvulsant Valproate Effects
Alopecia Hepatotoxicity Vomiting (give with food)
71
Anticonvulsant Primidone
Approved in dogs Metabolized to phenobarbital Very Hepatotoxic More expensive than phenobarbital Not controlled, not recommended Just use phenobarbital!
72
Anticonvulsant Phenytoin
Not reliable Not recommended Hepatotoxic
73
Anticonvulsant Phenytoin Problem at high doses
Zero-order kinetics @ high doses
74
Anticonvulsant Phenytoin Half-life
T 1/2b = 2hour (dogs) = ~100hr (cats)
75
Anticonvulsant Phenytoin Use in horses
Azoturia & antiarrhythmic treatment
76
Anticonvulsant Drugs to avoid!
P-FOB Phenothiazines Fluoroquinolones (+NSAIDS) Opioid agonists Butryophenones
77
Anticonvulsant Stopping treatment
Seizure-free for 1-2 years -Taper dose over ~6 months -2 weeks between dose changes -Retreat if seizures return