therap

Question 1

gaba effect on glutamate

Answer 1

glut is excitability, gaba inhibits glut

Question 2

gaba a recep

Answer 2

ionotropic (no mediators therefore stim is instant rxn)

Question 3

gaba b recept

Answer 3

metabotropic (req mediator therefore slower)

Question 4

phenytoin moa and ae

Answer 4

ae: ihib the conc of serotonin
moa: It alters Na+, K+ and Ca2+ conductance and membrane potential
Thereby at therapeuticconc, it blocks Na+ channels and inhibit the generation of repetitive action potential
req high loading dose + non zero/linear kinetics

Question 5

Carbamazepine moa use and ae

Answer 5

for focal (partial) and generalised tonic clonic seizures
can be used in combination with phenytoin
blocks Na+ channels inhibits high-freq repetitive firing of neurons
ae: potent microsomal enzyme inducer and it significantly interferes with clearance of ARVs
Spinabifida occur inapproximately 1% of the offspring of pregnant women treated with carbamazepine
can cause theSteven-Johnson syndrome

Question 6

Valproic acid moa

Answer 6

It increases levels of GABA in the brain
mechanism of action inpatients with absence seizures remain unexplained

Question 7

Ethosuximide use moa and ae

Answer 7

for less toxic drugs to treat absence seizures in children nb much lionger half life in infants and elderly because of red liver function
moa: It reduces theCa2+currents in the thalamic neurons
ae: Gastrointestinal side effects

Question 8

Gabapentin use moa

Answer 8

analogue of GABA originally developed for spasticity - so acts on the enzyme not the recept
moa: It increases the conc. and the rate of synthesis of GABAin the brain

Question 8

Phenobarbital use and moa

Answer 8

used to control most seizures
moa: It enhances the GABA receptors to prolong openings of Clchannels

Question 8

summary of moa of antiseiz drugs will come out in exam

Answer 8

will literally come out

Question 9

dopamine hypothesis

Answer 9

They block dopamine on D2 receptors in the mesolimbic system (hippocampus)of the brain
Sustained high-dopamine tone in the striatum has been proposed to contribute to hallucinations

Question 9

dopaminergic tracts and functions

Answer 9

nigrostriatal - motor control and vol movt
mesolimbic - mood and behav
mesocortical - speech and thinking
tuberinfundibular - secr of prolaction

Question 10

lithium pharm

Answer 10

competes with mg in enzymes
resp for recycling PIP2 which decrease conc of dopamine (inhib of IMPace enzyme)

Question 11

moa of dopamine

Answer 11

manic state- dec level of dopamine (depletion of myo-inositol through inhib of IMPase)
depression state- inc level of serotonin in dorsal and lat hippo ( byinhib GSK-3)`

Question 12

ae of lithium

Answer 12

inc blood ca2 and parathy H
thus inc risk of renal fx

Question 13

moa and indication of aripiprazole

Answer 13

ihib D2 recp post syn
partial presyn D2 agonist
acts partially agaisnt serotonin

ind- shizo in children
alternative for olanzapine induced hyperprolactinemia

Question 14

ae of nitrazepam

Answer 14

drowsiness and over sedation
ataxia
hypoten

Question 15

effects of age and water sol drugs

Answer 15

Total body water and lean body mass decreases.This means that water soluble drugs distribute less into the interstitial space, so there is more drug in the plasma , so plasma levels of the drug are higher. Higher plasma levels usually means the drug will have a greater effect.
-Digoxin is water soluble

Question 16

effects of age and lipid sol drugs

Answer 16

Body fat increases
This means that lipid soluble drugs distribute into the fatty tissues and then slowly move back into the plasma. This means the duration of action of the drug increases.
Nitrazepam is lipid soluble.

Question 17

effects of age and hepatic metab

Answer 17

Hepatic mass and hepatic blood flow decline with advancing age. This means that hepatic function decreases.
For drugs which are inactivated to a large extent by the liver, such as theophylline, caution is advised, as a decrease in hepatic function means that less drug is removed from the plasma and the plasma level increases.

Question 18

effects of age on Renal excretion

Answer 18

There is a decline in renal function and renal blood flow (even when there is no renal disease). This means that for drugs eliminated by the kidneys e.g. digoxin and ibuprofen, normal doses will result in increased plasma levels (ie less of the drug is cleared by the kidney) and toxic effects.

The decline in renal function is not necessarily reflected by ↑ serum creatinine
Acute illness can lead to rapid reduction in renal clearance especially if there is also dehydration

Question 19

Drugs associated with memory loss in the elderly

Answer 19

benzodiazepines***
statins
anticonvulsants
antidepressants (tricyclic antidepressants)
opiates
beta-blockers
dopamine agonists
anticholinergics
older antihistamines

Question 20

Drugs associated with anxiety in the elderly

Answer 20

quinolones

Question 20

Drugs associated with incontinence in the elderly

Answer 20

diuretics

Question 21

Drugs associated with urinary retention in the elderly

Answer 21

anticholinergics antihistamines e.g. diphenhydramine

Question 21

Drugs associated with falls in the elderly

Answer 21

benzodiazepines**** antidepressants (postural hypotension) antipsychotics NB prochlorperazine (frequently used inappropriately to treat ‘dizziness’)→postural hypotension hydrochlorothiazide (postural hypotension) alpha blockers e.g. doxazocin used for urinary retention

Question 22

Benzodiazepine withdrawal

Answer 22

Should be slow stepwise ↓ eg by 10% of daily dose every 2-4 weeks If using short or intermediate acting compound, change to equivalent dose of diazepam The duration of withdrawal schedule is dependant on the individual response. Requires counselling and support and may require adjuvant medication eg antidepressants, beta-blockers

Question 22

Drugs associated with delirium in the elderly

Answer 22

Anticholinergic** medication Benzodiazepines** Opioids** in high doses (morphine ↑ the release of dopamine) Digoxin** Beta-blockers especially propranolol Steroids in high doses All antidepressants. SSRIs: Paroxetine ↑↑antimuscarinic activity NSAIDs** Older antihistamines eg promethazine (anticholinergic properties) Alcohol or benzodiazepine withdrawal

Question 23

Delirium –clinical features

Answer 23

Disturbance of consciousness: ↓ focus, attention, awareness of environment Cognition or perceptual disturbance, includes memory problems, language disturbance, disorientation Features develop over hours to days and fluctuate throughout day Often do not look ill apart from behavioural changes Delirium may be only sign of underlying serious medical illness in elderly patients

Question 24

Treatment of delirium

Answer 24

Implement non-drug treatment Review medication list and look for temporal relationship, new drug, recent dose increase Stop/taper drug causing delirium Check renal clearance and adjust doses if necessary If needed, use antipsychotics to control behaviour problems of delirium: haloperidol is the drug of choice (least anticholinergic of the antipsychotics) Benzodiazepines may be useful to treat delirium of benzodiazepine or alcohol withdrawal and seizures

Question 25

Anticholinergic toxicity:

Answer 25

skin colour changes (red as a beetroot) dry mouth (dry as a bone) constipation or absence of bowel sounds

Question 26

Metabolite-mediated opioid toxicity:

Answer 26

Another cause of delirium with neurological hyperexcitability –high doses, rapidly increasing doses or low doses + renal toxicity