Drug Action 3 Flashcards
What alternative anxiolytics exist?
Bezodiazepine partial agonists and non-benzidiazepines
What non-benzodiazepines can be used to treat anxiety?
Buspirone - 5HT-1 agonist; CCK-R; mGLU-R
What is CCK-R?
Cholecystokinin receptor
What is mGLU-R?
Metabotropic glutamate receptor
What are the possible causes of epilepsy?
Genetic, head injury, local lesions, neoplasms, infections, febrile seizures
Outline genetic causes of epilepsy.
Mutations in ion channels - GABA-A, Na-v, AChR
What are the three main areas of epileptic activity?
Motor cortex - convulsions; hypothalamus - autonomic discharge (salivation and incontinence); reticular formation - loss of consciousness
What factors aggravate epilepsy?
Stress, fatigue, flashing lights, sudden loud noises, altered blood glucose levels, pH
What are the three main treatments for epilepsy?
Benzodiazepines, GABA uptake inhibitors, GABA metbolic inhibitors
Name four benzodiazepines used in the treatment of epilepsy.
Clonazepam, clobazam, diazepam, barbiturates
What are diazepam, clonazepam and clobazam used to treat?
Used IV for status epilepticus
What are the problems with diazepam, clonazepam and clobazam?
Sedation, tolerance and withdrawal
What are the problems with barbiturates?
Low therapeutic index, sedation, complez pharmacokinetics
Name a GABA uptake inhibitor.
Tiagabine
What is tiagabine?
GABA uptake inhibitor
What is tiagabine used to treat?
Convulsion
Name two GABA metabolic inhibitors
Vigabatrin and valproate
What are the problems with vigabatrin usage?
Depression
What are the problems with valproate usage?
High protein binding, rarely hepatotoxic, teratogenic
What does teratogenic mean?
Causing malformations to the embryo
From which respiratory pathway is GABA deriven?
Krebs cycle
Describe the deviation from the Krebs cycle that produces GABA.
Alpha-ketoglutarate + glutamine = glutamate; glutamate (+ GAD) = GABA
What three states do Na channels cycle through?
Closed - open - inactive
How do Na channel blockers treat epilepsy?
Block excitatory transmission at focus and limit spread of epileptiform activity with use-dependent Na channel inhibitors
Name three Na channel blockers.
Phenytoin, carbamazepine and lamotrigine
What are the problems with phenytoin use?
Complex pharmacokinetics, vertigo, ataxia, headaches, rashes
What are the problems with carbamazepine use?
Microsomal enzyme induction, shouldn’t be combined with other drugs
What are the problems with lamotrigine use?
Nausea, dizziness, ataxia and rashes
What type of drug is phenytoin?
Anti-epileptic
What is the MOA of phenytoin?
Na channel blocker
What type of drug is carbamazepine?
Anti-epileptic
What is the MOA of carbamazepine?
Na channel blocker
What type of drug is lamotrigine?
Anti-epileptic
What is the MOA of lamotrigine?
Na channel blocker
What are Ca channel blockers used for?
Epileptic absence seizures
Name two Ca channel blockers.
Ethosuzimide and GABApentin
What new targets are there for anti-epileptic drugs?
Proteins such as SV2A control the sensitivity of synaptic machinery
Name a drug that binds SV2A.
Levetiracetam
What does levetiracetam bind?
SV2A
What does levetiracetam do?
Alters the sensitivity of synaptic machinery
What is levetiracetam used to treat?
Epilepsy
What type of drug is felbamate?
Anti-epileptic
What type of drug is topiramate?
Anti-epileptic
What is the MOA of felbamate?
Weak NMDA channel blocker
What is the MOA of topiramate?
AMPA channel blocker
Name a weak NMDA channel blocker used to treat epilepsy.
Felbamate
Name an AMPA channel blocker used to treat epilepsy.
Topiramate
What are the two kinds of depression?
Unipolar and bipolar
Characterise unipolar depression.
Mood swing always in the same direction
What are the two kinds of unipolar depression, and what are their proportionate incidence?
Reactive - 75%; endogenous - 25%
Characterise bipolar depression.
Depression alternates with mania - characterised by excessive exuberance, enthusiasm, self-confidence that may be combined with irritability, impatience and/or aggression
Outline the typical symptoms of depression.
Low mood, negative thoughts, misery, pessimism, apathy, sever loss or gain in weight/appetite, low self-esteem, feelings of worthlessness or guilt, sleep disturbance, loss of libido, diminished ability to think/concentrate
What is the male:female ratio of depression patients?
Two to one
Outline the typical outcomes of depression on the individual.
15-30% commit suicide; mortality is generally greater that healthy people due to increased incidence of cardiovasular disease and cancer
Characterise post-natal depression.
Usually occurs 2-8 weeks after delivery and can stay up to a year after birth; babies’ brain waves can become altered if the mother is depressed
Outline why treatment for depressed patients is important.
Depression can cause changes in brain chemistry that can only be reversed by drugs, and depression can remain long after cause due to the biochemical changes at synapses
What possible physiological causes are there for depression?
Hormonal function disturbance, alteration to the pre-frontal cortext/hippocampus & amygdala, NA and 5HT deficits, reduced BDNF neurogenesis, NMDA neurodegeneration
What hormonal function disturbances can cause depression?
CRH hyperfunction, high blood cortisol levels (stress)
What can a functional deficit in NA & 5HT cause?
Depression and long term trophic effects
What does BDNF stand for?
Brain derived neurotrophic factor
What are the four main classes of antidepressants?
Selective serotonin reuptake inhibitors, classical tricyclic antidepressants, monoamine oxidase inhibitors, monoamine receptor antagonists
Name a selective serotonin reuptake inhibitor.
Fluoxetine
Name a classical tricyclic antidepressant.
Imipramine
Name two monoamine oxidase inhibitors.
Phenylzine and moclobemide
What type of drug is fluoxetine?
Antidepressant
What is the MOA of fluoxetine?
Selective serotonin reuptake inhibition
What type of drug is imipramine?
Classical tricyclic antidepressant
What type of drug is phenylzine?
Antidepressant
What is the MOA of phenylzine?
Monoamine oxidase inhibition
What type of drug is moclobemide?
Antidepressant
What is the MOA of moclobemide?
Monoamine oxidase inhibition
What are the two types of cholinergic receptor?
Nicotinic and muscarinic
What agonists stimulate ALL autonomic ganglia?
Nicotinic ligand-gated ion channel agonists
What is another name for muscarinic agonists?
Parasympathomimetics
Outline the five steps in cholinergic transmission.
NT synthesis, storage in synaptic vesicles, release upon neuronal activation, post-synaptic receptor activation, breakdown and/or reuptake
What synthesises cholinergic NTs?
Choline acetyltransferase
What does CAT stand for?
Choline acetyltransferase
What does CAT do?
Synthesises cholinergic NTs
What breaks down cholinergic NTs?
Acetylcholinesterase
What does AChE stand for?
Acetylcholinesterase