Neurological Flashcards
Example of dopaminergic drugs
levodopa, co-carledopa
how does levodopa work
it is a precursor of dopamine that can enter the brain via a membrane transporter (dopamine cannot enter the brain as it cannot cross the blood-brain barrier) - increasing dopaminergic stimulation to the striatum
how is levodopa given
with a de-carboxylase inhibitor to form co-carledopa as this decreases peripheral conversion hence decreasing side effects
when is levodopa used
Parkinson’s disease and Parkinsonism
contraindications of levodopa
caution in elderly, CVS disease and other psych disorders
side effects of levodopa
nausea, vomiting, drowsiness, confusion, hallucinations, hypotension, has a wearing off effect, too much causes dyskinesia
possible interactions of levodopa
metoclopramide (opposing effects on dopamine receptors), anti-psychotic drugs
what is phenytoin
anti-convulsant
how does phenytoin work?
decreases neuronal excitability and conductivity, thus decreasing spread of seizure activity
- thought to do this by binding to sodium ion channels thus preventing sodium influx and hence preventing action potentials
when is phenytoin used
- seizures and static epileptics (second line)
- generalised and focal seizures in epilepsy
contraindications in phenytoin
- careful in pregnancy
- reduce dose in hepatic impairment
side effects of phenytoin
acne, hirsutism, gum hypertrophy, haematological disorders, osteomalacia, euro effects (nystagmus, ataxia, dis-coordination)
possible interactions with phenytoin
decreases the efficacy of drugs metabolised by P450 inhibitors such as oestrogen, progesterone and warfarin
how does carbamazepine work
- inhibits neuronal Na channels, decreasing excitability and hence inhibits spread of seizure activity
- blocks synaptic transmission in the trigeminal nucleus, thus controlling neuralgic pain
when is carbamazepine used
- epilepsy (1st line in clonic-tonic and focal seizures)
- trigeminal neuralgia
contraindications for carbamazepine
cautious in pregnancy (neural tube defects), renal, hepatic and CVS disorders, not to be used if anti-epileptic sensitivity syndrome
side effects of carbamazepine
GI disturbance, oedema, dizziness and ataxia, hypernatraemia, anti-epileptic sensitivity syndrome
possible interactions of carbamazepine
- cytochrome P450 inhibitors
- decreases efficacy of drugs metabolised by cytochrome P450 enzymes (warfarin, progesterone, oestrogen)
- other anti-epileptic drugs
how does sodium valproate work
- inhibits neuronal Na channels, decreasing excitability and hence inhibits spread of seizure activity
- increases GABA in the brain, regulating neuronal excitability
when is sodium valproate used
- epilepsy (1st line in most types of seizure)
- established convulsive status epilepticus
- bipolar disorder
contraindications of sodium valproate
- conception / child bearing age
- 1st trimester of pregnancy
- hepatic and renal impairment
side effects of sodium valproate
GI disturbance, neuro and psych effects such as ataxia, tremor, behavioural disturbance, thrombocytopenia, hair loss
possible interactions of sodium valproate
- cytochrome P450 inhibitors
- decreases efficacy of drugs metabolised by cytochrome P450 enzymes (warfarin, progesterone, oestrogen)
how does lamotrigine work
blocks Na channels, decreasing convulsive activity and stabilising neuronal activity
- also blocks some Ca channels
