Anticonvulsants and Stimulants Flashcards
What is the MOA of carbamazepine (Tegretol)?
blocks Na channels = blocks propagation of impluses
decreases pre-synaptic transmission
What drug has the following known side effects: aplastic anemia, agranulocytosis, thrombocytopenia, rashes, altered skin pigment, alopecia, hepatoxicity, congestive heart failure, changes in BP?
carbamazepine (Tegretol)
Cabamezepine (Tegretol) is a classic inducer of what type(s) of drugs?
Dec. warfarin, doxycycline, theophylline and oral contraceptive effectiveness
cabamezepine (Tegretol) increases the hepatotoxicity associated with what medication?
acetaminophen
Toxic blood levels of cabamezepine (Tegretol) can occur with simultaneous use of what other drug?
erythromycin-type antibiotics (macrolides)
What is the MOA of phenytoin (Dilantin)?
- Stabilizes neuronal membranes by decreasing the neuronal membrane passage of Na/Ca ions
- Interferes with Ca mediated release of NT
- Reduces propagation of abnormal impulses in the brain to reduce the frequency of seizures
What medication is associated with the following adverse effects:
- megaloblastic anemia
- osteoporosis
- gingival hyperplasia
- hirsutism
phenytoin (Dilantin)
How does phenytoin (Dilantin) cause megaloblastic anemia?
by interfering with Vit B12 metabolism
How does phenytoin (Dilantin) cause osteoporosis?
By creating Vit D and folate deficiencies
What is the first symptom of folate deficiency seen as a result of Dilantin use?
oral mucosal ulceration or glossitis
T/F gingival hyperplasia associated with Dilantin use will regress with improved OH and drug termination
True
What is a recommended tx procedure to prevent gingival hyperplasia in patients taking Dilantin?
carbamazepine is sometimes used before phenytoin to avoid gingival hyperplasia
What are the teratogenic effects of Dilantin and what FDA category is is classified as?
Fetal syndrome: includes cleft lip, cleft palate, congenital heart disease
FDA category D
What is the MOA of GABAmimetic agents?
release of GABA from presynaptic interneurons = increase GABA fusion w/ presynaptic neurons
inhibit release of ACH from presynaptic neurons
What is the MOA of phenobarbital (Luminal)?
reduces Na/K transport along axonal membranes
potentiates inhibitory effects of GABA mediated neurons
What drug can produce hyperactivity in children and increases bleeding time?
valproic acid (Depakene)
What is the drug of choice for tx of absence seizures (petit mal)?
ethosuximide (Zarontin)
What drug is not effective in treating absence seizures (petit mal)?
phenytoin (Dilantin)
What two benzo can be used for tx to seizures?
clonazepam (Clonipin): all types of seizures
diazepam (Valium): status epilepticus and local anesthetic induced
When would a person use gabapentin (Neurontin)?
partial seizures and tonic-clonic
chronic pain
post-herpetic neuralgia (shingles)
What is a major side effect of gabapentin (Neurontin)?
oral mucositis
T/F gabapentin (Neurontin) has many drug interactions
False - it has very few since it is not metabolized
What is the MOA of lamotrigine (Lamictal)?
inhibit release of glutamate (excitatory amino acid)
inhibits voltage sensitive Na channels
stabilize neuronal membranes
weakly inhibits serotonin receptors
Which anticonvulsants act as hepatic cytochrome P450 inducers?
phenytoin (Dilantin)
phenobarbital (Luminal sodium)
carbamazepine (Tegretol)
How does metabolism of anticonvulsants differ based on doses?
Low dose = first order
High doses/liver enzyme saturation = zero order
T/F anticonvulsants cure epilepsy
False - drugs are used for symptomatic tx
T/F when adding additional anticonvulsants you must change the metabolism of all anticonvulsants
True
What drug is able to tx the following conditions:
- simple and complex partial seizures
- management of bipolar depression
- management of chronic pain
- Dental: trigeminal neuralgia (tic douloureux)
carbamazepine (Tegretol)
what are indications for phenytoin (Dilantin) use?
- simple and complex partial seizures
- tonic-clonic seizures
- status epilepticus
- dental: trigeminal neuralgia
What drug has the following indications for use:
- anticonvulsant
- tonic-clonic seizures
- partial seizures
phenobarbital (Luminal sodium)
What drug is the most common barbiturate used as an anticonvulsant?
phenobarbital (Luminal sodium)
What are the indications of use for primidone (Mysoline)?
partial seizures
tonic-clonic seizures
What are the indications of use for Valproates (Depakote)?
tonic-clonic seizures (grand mal)
generalized seizures: absence (petit mal), myoclonic
What is the first drug of choice for absence (petit mal) seizures? (think children)
ethosuximide (Zarontin)
What type(s) of seizures can the benzo clonazepam (Clonipin) be used to tx?
All types!
What are the indications for gabapentin (Neurontin)?
partial seizures
tonic-clonic
chronic pain
post-herpetic neuralgia (shingles)
What are the indications for lamotrigine (Lamictal)?
partial seizures
tonic-clonic
part of tx for bipolar disorder
What convulsant is used for provocative dx of epilepsy?
pentylenetetrazole (Metrazole)
Valium is indicated in what 2 situations?
- local anesthetic induced seizures in dental office
2. status epilepticus
When would a stimulant be used in medicine?
antidote for depression: analeptics
reverse respiratory, cardiac and CNS depression
What are the 3 primary classes of stimulants?
Xanthenes
Centrally acting sympathomimetics
Convulsants
What is the main effect of Xanthenes and its tx use?
bronchodilators
asthma tx
What is the main effect of centrally acting sympathomimetics and its tx indications?
amphetamine
tx: hyperkinetic children, diet pills
What is the main purpose of convulsant medications?
diagnostic
What are the common xanthene medications?
aminophylline
theophylline
caffeine
At what dosages of caffeine are the following structures effected:
- cerebral cortex
- brain stem
- spinal cord
- 50-200 mg
- > 250 mg
- 100 mg
T/F caffeine and theophylline are equally effective on the CNS?
True
Theophylline produces (more/less) effects on blood vessels, heart, smooth muscle, diuresis than caffeine does
Theophylline produces more than caffeine
Theophylline > Caffeine
Theophylline produces (more/less) effects on skeletal muscle than caffeine does
Theophylline produces less than caffeine
Theophylline
What what dosage does caffeine toxicity occur?
300 mg
What type of caffeine in take results in physical dependence?
5+ cups/day
What type of medication can be used to tx acute pulmonary edema and apnea in perterm infants?
Xanthenes: increases perfusion, decreases peripheral resistance causing bronchiodilation
CNS sympathomimetics increase or decrease the following:
- fatigue
- mood, motor activity, performance, wakefulness
- REM sleep
- appetite
- satiety center
- medullary respiratory center
- decrease
- increase
- decrease
- decrease
- increase
- increase
What drug type(s) have the following indications of use:
- narcolepsy
- hyperkinetic syndrome
CNS sympathomimetics
What is the popular drugs used for the management of children with hyperkinetic disorders?
Centrally acting sympathomimetics (amphetamine)
Why vasoconstrictors (epinephrine) must be used with caution in dental patients taking CNS sympathomimetics?
CNS sympathomimetics block reuptake of dopa and NE
inhibit MAO
Enhances sympathomimetic response of Epi/NE
What is the MOA of cocaine?
blocks Na/K ATPase reuptake mechanism
dopa and NE remain in synapse
crosses blood brain barrier
What 4 things do cocaine clinically increase?
- sympathetic system responses
- peripheral resistance
- cardiac output
- energy expenditure
What is the MOA of pentylenetetrazol (Metrazole)?
decreases neuronal recovery time by increasing K+ permeability
used for provocative dx of epilepsy
What is the MOA of strychnine?
blocks glycine receptors on Renshaw cells (postsynaptic inhibition)
produces generalized convulsion → non-spontaneous, simultaneous tonic convulsion of flexors and extensors
What drug causes OD when added to heroin?
strychnine (rat poison)
What are the effects of nicotine based on dosage level?
Low doses: stimulates nicotinic receptors in brainstem and cortex
High doses: tremor, emesis and stimulation of respiratory center
Higher doses: convulsions (can be fatal)
