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105 Cards in this Set
- Front
- Back
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Major drug classes of anticonvulsants?
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Barbituates
Benzodiazepine Potassium Bromide Valproic Acid Gabapentin |
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What is a seizure?
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refers to an abnormal behavior
Abnormal discharges of cortical neurons. That may spread throughout the entire brain or be focal A Seizure is an observable phenomenon that is finite in time |
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Epilepsy?
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A chronic condition characterized by recurrent seizures.
A syndrome w/a cluster of symptoms & signs that occur together Unlike a disease, an epileptic syndrome does not have a single known etiology or pathology. cannot be diagnosed simply by direct observation or video review |
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How can you diagnose epilepsy?
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Based on pertinent information:
age of onset, etiology, genetic information, seizure frequency, imaging studies, precipitating factors, electroencephalography (EEG) and natural history. |
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Focal (or partial) epilepsy?
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may have simple partial, complex partial and secondarily generalized tonic-clonic seizures (e.g., partial seizures with secondary generalization).
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Generalized epilepsy?
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one or more of the following seizure types: absence, myoclonic, tonic, clonic, tonic-clonic and atonic.
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Can one seizure type define epilepsy?
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No. No seizure type is specific for a single type of epilepsy.
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Symptoms of gran mal seizures?
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Patients become unconsciousness followed by depression and or sleep lasting a few minutes up to hours
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Symptoms of status epilepticus?
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Patients fail to recover to a normal alert state between repeated tonic-clonic attacks or episodes that last at least 30 minutes.
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How do you treat convulsive seizures?
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As a medical emergency; you must treat with anticonvulsants.The longer an epileptic seizure persists, the greater neuronal injury, morbidity, and mortality.
Continuous muscle contraction leads to hyperthermia that can be life threatening. |
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Common physical sign of seizure?
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Scar on forehead.
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Breeds that are likely to have seizures?
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beagles,
all shepherds, border collies, boxers, cocker spaniels, dachshunds, retrievers (golden, Labrador), Irish setters, poodles, St. Bernards, shelties, Siberian huskies, Springer spaniels, welsh corgis, and wire-haired fox terriers |
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Gran mal series of events in dogs:
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Normal
Stagger Back uo & sits down on hind limbs Muscle fasciulations begin : facial muscles, eyelids, jaw muscles spasm Dog chattering teeth, salivate, foaming Appear to yawn but no voice or noise is heard Fall over and stretches out with extension of front and hind limbs & Neck extends Eyes rolled back and foaming at the mouth Dogs are now in a rigid extensor position and is unable to breathe due to extensive muscle contraction A few seconds later, the dog begins to relax and breathing returns to normal Some dogs lose consciousness if breathing is markedly interrupted Some animals get up and begin moving around Others remain unattentive for a period of time or go to sleep |
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Types of seizures in felines?
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Petite mal, grand mal, status epilepticus.
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Gran mal seizure in cat?
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most common form ;lasting >5 min.
cat falling to one side, urinating or defecating uncontrollably paddling the feet as if swimming, frothing at the mouth, and it may cry out loud Cats are generally unaware of their surrounding |
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Equine epilepsy:
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Unconscious, collapse, tremble and shake
Ears or tail may tremble Eyes will glaze over, giving a distant or vacant appearance Horse return to normal Differentials Epilepsy Tumors Infectious diseases Parasitic worms Equine protozoan encephalitis |
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How do we monitor Drug Monitoring?
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Factors: solubility, protein binding, size, affinity, route
Therapeutic drug monitoring (TDM) Peak, trough, steady state, clearance (renal, hepatic, total), half-life, bioavailability, etc. |
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Mechanisms of seizures?
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Altered neuronal membrane function which can lead to excessive depolarization
Decreased inhibitory NTs, e.g., GABA Increased excitatory NTs, eg, glutamate Altered extracellular potassium and calcium levels (Increased K+ and decreased Ca++) increase neuronal excitability and facilitate the initiation and spread of seizures. Once initiated, the seizure discharge may synchronize with other neurons and propagate to surrounding areas of the brain |
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What makes an anticonvulsant effective?
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Anticonvulsants that act at more than one mechanism!
AEDs that act at the GABA receptor tend to >>> efficacious |
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Can you cure epilepsy? And what is the route for medication since it is lifelong?
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No, not normally. Medication is given orally (Phenytoin not absorbed the best orally). IV in case of emergency!
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Are anticonvulsants water soluble?
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NO -- they are lipid soluble with a wide Vd giving it great capacity to hit the CNS.
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Is diazapam more effective than phenobarbitol?
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YES. Diazapam is the drug of choice for status epilepticus in dogs & cats b/c it crosses the BBB. 90% more effective, less protein binding.
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What are the drugs under the Barbituate Class of AEDs?
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Phenobarbitol, Primidone, Pentobarbitol. Also, thimylal & thiopental.
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What are the drugs under the Hydantoin Class of AEDs?
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Phenytoin
Mephenytoin |
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What are the drugs under the Benzodiazepine Class of AEDs?
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Diazapam
Clonazapam Midazolam Clorazepate |
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What is the first and sole TX for canine epilepsy?
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POTASSIUM BROMIDE.
Not recommended for cats. |
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How does phenobarbitol work?
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depresses the motor centers of cerebral cortex, giving it excellent anticonvulsant properties; (multiple antiseizure effects)
Widest anticonvulsant spectrum (broad spectrum) Most effective anticonvulsant to inhibit progressive intensification of seizure activity |
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Primary MOA of phenobarbitol?
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Enhancing responsiveness to the inhibitory postsynaptic effects of GABA. Increases seizure threshold.
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In which animals is phenobarbitol preferred?
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Dogs & cats.
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How do we give Phenobarbitol?
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Oral and IV. Is 60-80% effective. Eliminated in the urine.
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Adverse effects?
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seizures * drugs that lower seizure threshold induce seizures (ace) * enzyme induction * hepatotoxicity (most common) * interacts w drugs to inhibit drug metabolism * toxicosis (tolerance, weight gain, pupd)
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Most adverse effect of Phenobarbitol?
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Hepatic toxicity from enzyme induction.
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Trade names for Primidone?
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Mylepsin & Mysoline
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What is primidone effective for in dogs?
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primary epilepsy, epileptiform seizures, virus encephalitis, distemper
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Adverse effects of primidone?
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hepatotoxicity: increased liver enzymes;
anxiety and agitation (similar to phenobarbital. Not for use in cats. |
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Trade names of Pentobarbitol
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Nembutal, Sodium Pentobarbital
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Why is Pentobarbitol not a first line drug for epilepsy?
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B/c it is also a euthanasia agent. Also, not rec in cats. Give slowly IV for epilepsy.
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Adverse effects of pentobarbitol?
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Severe cardiopulmonary depression. USE W CAUTION IN CATS.
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When would we use phenytoin?
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As a supplement w phenobarbitol. Longer half life in cats. Can cause cardiac arrythmias.
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Adverse effects of mephenytoin?
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Possible blood dyscracias and hepatotoxicity
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Are the benzodiazipines lipiophilic?
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YES, HIGHLY protein bound making it all the more effective compared to pentobarb.
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How does diazipam work?
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Benzodiazepines decrease seizure spread and block arousal and centrally depress spinal reflexes --Binds gaba receptor; potentiates inhibitory effects of GABA in brain and spinal cord.
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One big side effect of diazipam that makes it hard to use all the time for maintence tx?
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Tolerance to diazepam develops rapidly. Other adverse effect is SEDATION.
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Clonazepam?
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more potent than diazepam,
tolerance develops not effective for chronic therapy |
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Why would we use Midazolam?
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B/c more potent than diazepam, anticonvulsant, muscle relaxer, tranquilizer, appetite stimulant; status epilepticus in the dog.
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Adverse effects of Midazolam?
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venous thrombosis, cardiovascular depression, arrthymias.
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Adverse effects of Clorazepate?
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dependence, and seizures upon withdrawal
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Is potassium bromide approved for vets in the US?
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No.
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MOA of Potassium bromide?
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generalized depression on neuronal excitability. Bromide competes with CL- transport across membraneshyperpolarized membrane (may be synergistic with phenobarbital.
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Indications of K+Bromide?
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First and sole treatment for canine epilepsy
Refractory seizure disorders in dogs; Adjunctive therapy with phenobarbital 2nd and 3rd drug for seizures in cats |
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When should we not use potassium bromide?
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In animals with liver dysfunction because it has a very long half life.
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Side effects of Potassium Bromide?
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bitter taste, gastric irritation, nausea, PUPD, polyphagia, sedation, ataxia
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Bromide Toxicosis?
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Neurological signs: lethargy, disorientation, delirium, and ataxia
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Trade names for Valproic Acid?
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Depakene, Depacon
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Why do vets use Valproic acid even though it is not labeled for vets in the US?
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Has been used as an adjunct to phenobarbital and primidone in dogs with refractory seizures
Also used to treat aggressive behavior problems |
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Trade name for Gabapentin?
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Neurontin
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In human medicine Gapapentin is used as a secondary/add-on drug to treat refractory seizures. What animals do we use it on in vet med?
Pain relief |
dogs and horses
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Issues we should be mindful of when using gabapentin?
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Therefore, excretion is decreased in patients with renal impairment and decreased cardiac function, and in elderly patients
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Trade name for Lamotrigine? It is mostly used in human medicine.
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Lamictal
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Adverse effects of Lamotrigine?
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dizziness, ataxia, somnolence, headache, blurred vision, nausea, vomiting and rash.
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Trade name for Felbamate?
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Felbatol
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Drug of choice for status epilepticus in dogs, cats, & horses?
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Diazepam
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Second tier DOC for dogs with status epilepticus?
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phenobarbital, Na pentobarbital
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Second tier DOC for cats with status epilepticus?
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Na pentobarbital
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Second tier DOC for horses with status epilepticus?
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guaifenesin, Thiamylal
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Maintence RX for dogs with status epilepticus?
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Dogs:Phenobarbital, primidone, clonazepam, chlorazepate, valproic acid
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Maintence RX for horses with status epilepticus?
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diazepam, phenobarbital, phenytoin
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Maintence RX for cats with status epilepticus?
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diazepam, phenobarbital
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Analeptic CNS stimulants?
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Doxaprom
Apomorphine Caffeine Ephedrine 4-Aminopyridine (4-AP) Yohimbine (competitive alpha2 agonist) Nicotine |
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Trade name for Doxapram?
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Dopram
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Primary use of doxapram/dopram?
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stimulate respiratory activity by directly stimulating chemoreceptors of the carotid and aortic regions. Also stimulate medullary respiratory center, increasing the tidal volume
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How do you reverse respiratory depression in a dog with AEDs?
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Doxapram:sublingually/topically/SC at 1-5 mg.
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How do we give apomorphine?
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IM, SC, conjunctiva
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What is apomorphine used for and in which animal should we avoid use?
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emetic; cats.
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What are Methylxanthines(MX)?
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Caffiene, theophylline, theobromine, aminophilline.
Alkaloids with a xanthine nucleus |
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What do MX's do?
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MXs are bronchodilators, stimulants of CNS & CVS
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Name the classes of neuroleptics:
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Antipsychotics
Antidepressants |
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Name the types of antidepressants:
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MAOIs
SSRIs TADs Anxiolytics Anxioselectives |
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Name the MAOI that is irrerversible?
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selegiline
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Name the 2 SSRI's most commonly used in human medicine?
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Sertraline (zoloft)
Fluoxetine (prozac) |
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Name the drugs used as antipsychotics:
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Phenothiazines: Chlorpromazine, acepromazine, haloperidol
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name the TADs:
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Clomipramine, amitripine, desimpramine
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Anxiolytics?
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benzodiazepines: diazepam, lorazepam
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Anxioselectives?
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Buspirone
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What is the common drug used to treat seperation anxiety in pets?
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Clomicalm
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How do we use anxiolytics in vet med?
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Diazepam has been used to treat fear-related behaviors in animals
-thunderstorm anxiety in dogs Social anxiety in cats decrease urine spraying Taming of wild animals Correction of sleep disorders in dogs Appetite stimulation in cats |
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Negative side effect of anxiolytics such as diazepam?
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Agression increased & doesn't treat fear aggression.
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Prototype for low potentcy antipsychotics?
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ACE
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Uses of antipsychotics in vet med?
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: tail chewing, growling, snapping, barking
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Side effects of antipsychotics in vet med (like ACE)?
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sedation, anticholinergic, alpha blockade
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High potentcy antipsychotic in vet med?
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Haloperidol
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Side effects of haloperidol?
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less sedation, autonomic effects, more commonly cause extrapyrimidal effects of parkinsonism, dystonia, dyskinesia, and akathisia
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What drugs do we use in vet med for mood stabilization?
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lithium, carbamazepine, Valproic acid
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Mood stabilizers in vet med TX what?
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biopolar, aggression
**Carbamazapine: tx cats that with fear related aggression against humans |
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Adverse effects of mood stabilizers?
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PUPD. Lithium toxicity (weight gain)
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TADs
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Amitryptyline
Impipramine Clomipramine |
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What is Amitryptyline used for in cats?
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urine marking, hypervocalization
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What is Amitryptyline used for in dogs?
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: Separation anxiety, anxiety related aggression; urination due to submission or excitement, allergy related pruritis
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Side effects of Amitryptyline?
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vomiting, hyperexcitability, sedation, arrthymias, orthostatic hypotension, mydriasis
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What drug is FDA approve for use in dogs for separation anxiety?
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Clomipramine (Clomicalm*)
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What else can clomicalm be used for in vet med?
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Urination due to submission or excitement
Reduce lick behavior (lick granuloma) |
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Fluoxetine(Prozac) treats what?
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Psychogenic alopecia,
allergy-related pruritis, dominance-related aggression, fearful behaviors obsessive-compulsive behaviors |
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What is the trade name for prozac in dogs?
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RECONCILE
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what do we use Anipryl (L-Deprenyl) for?
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Cushing’s disease, an adrenal hormone imbalance
Senile mental deterioration |
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Side effects of Anipryl?
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vomiting, diarrhea, drowsiness,
disorientation, hair loss, and shaking. |
