Neuro Flashcards
What class of drug is levodopa and how does it work ?
Dopamine precursor
- crosses blood brain barrier and converted not dopamine by dopa carboxylase therefore replacing deficient dopamine in basal ganglia
What class of drug is metoclopramide
Antiemetic
What are the indications for levodopa ?
- idiopathic Parkinson’s disease
- Parkinsonism
What are the contraindications for levodopa?
- closed angle glaucoma
- drug-induced Parkinsonism
What are the common side effects of levodopa?
Anorexia, nausea, vomiting, abdo pain
Insomnia, agitation, postural hypotension
Discoloured urine
Possible interactions of levodopa ?
Anaesthetics: increased risk of dysrhymias
MAOIs (antidepressants): increased risk of HTN
What drug class is phenytoin ?
Anticonvulsant
Mode of action of phenytoin ?
Blocks voltage gated Na+ channels therefore preventing influx of sodium and so preventing spread of epileptic charge
Indications for phenytoin ?
All epilepsy except absence seizures
Trigeminal neuralgia
There are no contraindications for phenytoin, but when should you take caution ?
Hepatic impairment
Pregnancy/breast feeding
Common side effects of phenytoin ?
Dizziness, headache, confusion, insomnia, nausea, vomiting
Possible interactions of phenytoin ?
Induces hepatic drug metabolising enzyme
What drug class is carbamazepine ?
Anticonvulsant
How does carbamazepine work ?
Increases the release of GABA - has inhibitory role in CNS, blocking Na+ channels and so preventing positive influx of Na
Indications for carbamazepine
Seizures: partial and tonic clonic (but may exacerbate absence & myoclonic)
Trigeminal neuralgia
Chronic neurogenic pain
Bipolar prophylaxis
Contraindications of carbamazepine
AV conduction abnormalities
Bone marrow suppression
Carbamazepine has cross sensitivity with which other anticonvulsants ?
Oxcarbazepine, phenytoin
Interactions of carbamazepine
Alcohol: CNS side effects increased
Tramadol: reduced effect
Paracetamol: increased metabolism
Side effects of carbamazepine
Dry mouth, nausea, vomiting,
Ataxia, dizziness, drowsiness,head ache, hyponatraemia
What drug class is sodium valproate ?
Anticonvulsant
Mode of action of sodium valproate
Inhibits GABA transaminase causing increased GABA in brain which has an inhibitory role preventing excitation - decreases levels of aspartate (excitatory neurotransmitter) and prevents influx of Na+
Indications of sodium valproate ?
All forms of epilepsy
Migraine prophylaxis
Mania
Contraindications of sodium valproate ?
Family history of severe hepatic dysfunction/active liver disease
Acute porphyria
Common side effects of sodium valproate ?
GI irritation- nausea, diarrhoea
Weight gain, transient hair loss,
hyperammonaemia, thrombocytopenia
Interactions of sodium valproate
Aspirin enhances effect of valproate
What class of drug is lamotrigine ?
Anticonvulsant
Mechanism of action of lamotrigine
Stabilises presynaptic neuronal membranes by hi biting sodium currents by selectively binding to the inactive state of of the sodium channel and subsequently suppressing release of excitatory amino acids e.g, glutamate and aspartate
Indications for lamotrigine
Seizures: focal and generalised including: tonic clonic, Lennox-gestaut, absence in children
- prevention of depressive episodes in bipolar
Common side effects of lamotrigine
Nausea, vomiting, dry mouth,
Aggression, agitation, headache, drowsiness, dizziness, tremor, insomnia,
Rash
Interactions of lamotrigine
Rifampicin- decreases plasma conc of lamotrigine MAOIs COCP- decreases plasma conc lamotrigine Carbamazepine ' ' Phenytoin- '' Valproate- increased conc lamotrigine
Mode of action of metoclopramide
Acts on chemoreceptors in trigger zone of brain stem to block dopamine receptors causing relaxation of pylori. Sphincter, increased rate of gastric/duodenal emptying
Indications for metoclopramide
Nausea and vomiting
GORD
Contraindications of metoclopramide
Parkinsonism
Recent gastric surgery (within last few days)
Intestinal obstruction
Side effects of metoclopramide
Common : acute dystonia reactions (muscle spasms)
Possible interactions of metoclopramide
NSAIDs- increased absorption of the, and therefore increased side effects
