• Announcements

    • Gurpal

      New question bank for paper B   05/11/18

      Please see the link below for a new question bank: http://www.superegocafe.com/online-courses/mrcpsych-paper-b-multiple-choice-question-bank/  
Sign in to follow this  
Followers 0
Gurpal

Part II ISQ Club - Pharmacology

48 posts in this topic

Part II ISQs will be posted regularly. You are encouraged to post a reply in the thread, stating whether you think an ISQ is true or false and why (eg. a short explanation, with reference to the textbook you used). Please only deal with one ISQ in each post and include the question as the first line of your post.

In a few days this ISQ Club thread will be moved to the Question Bank board. If you submit an answer, your status will be changed to 'Question Bank member' and you will be able to see the Question Bank board. Please allow up to 48 hours for this change to happen.

1. Aripiprazole is a D2 partial agonist

2. Aripiprazole is a 5HT2 antagonist

3. Physical dependence can develop in long term procyclidine use.

4. NMDA channels are blocked by magnesium ions.

5. Serotonin receptors are all metabotropic.

6. Magnesium inhibits glutamate receptors.

7. Pindolol blocks pre and post synaptic 5HT receptors.

8. Caffeine and false positive dexamethasone suppression test.

9. Caffeine interacts with benzodiazepines.

10. Caffeine interacts with clozapine.

11. There is an interaction between St. John’s Wort and contraceptive medication.

Share this post


Link to post
Share on other sites

4. NMDA channels are blocked by magnesium ions.

TRUE

KS CTP Ch 1.5

NMDA receptors mediate excitatory neurotransmission in the CNS in different ways from AMPA and kainate receptors. They are characterized by voltage-dependent block by magnesium ions (Mg2+), a high permeability to Ca2+, and slow gating kinetics.

Share this post


Link to post
Share on other sites

5. Serotonin receptors are all metabotropic.

False

Reference: Google :)

http://www.google.co.uk/search?q=cache:uXfcmva4594J:www.mnstate.edu/dalhouse/Psy345/powerpoints/Ch4.ppt+serotonin+ionotropic+metabotropic&hl=en

Serotonin Receptors

There are at least 9 types of 5-HT receptors

5-HT1 : 1A, 1B, 1D, 1E, and 1F

5-HT2 : 2A, 2B, and 2C

5-HT3

5-HT3 receptors are ionotropic, the remainder are metabotropic

5-HT1B and 5-HT1D are presynaptic autoreceptors

Share this post


Link to post
Share on other sites

9. Caffeine interacts with benzodiazepines.

10. Caffeine interacts with clozapine.

11. There is an interaction between St. John’s Wort and contraceptive medication

All true

Share this post


Link to post
Share on other sites

7. pindolol blocks pre and post synaptic 5ht2 receptors. true

check sleep research on line

8. caffeine causes false positive DST. false

false positive test is caused by alcohol pregnancy

Share this post


Link to post
Share on other sites

1. True - Aripiprazole is a partial agonist at the D2 receptor, a partial agonist at 5HT1a and an antagonist at 5HT2a receptors. It is being marketed as a 'dopamine-serotonin system stabiliser'.

Manchester Course

Share this post


Link to post
Share on other sites

2. True - Aripiprazole is a 5HT2a antagonist.

Manchester Course

Share this post


Link to post
Share on other sites

3. False - procyclidine is liable to abuse due to its euphoric effect,i.e. possible psychological dependence, but there is no mention of physical dependence in the BNF.

Share this post


Link to post
Share on other sites

4. True - the NMDA receptor channel is normally blocked by the binding of a Mg2+ ion, and so it seems likely that it is normally silent and that the normal signalling function of glutamate must take place via the other receptor types.

Companion to Psychiatric Studies (p.48)

Share this post


Link to post
Share on other sites

5. False - 5HT3 receptors act via ionic channels.

Companion to Psychiatric Studies (p.58)

Share this post


Link to post
Share on other sites

7. False - Pindolol blocks 5HT1a somatodendritic autoreceptors.

Essential Psychopharmacology (Stahl, p.278)

Share this post


Link to post
Share on other sites

10. True - caffeine increases serum clozapine concentrations by inhibiting CYP450 1A2.

Manchester Course

Share this post


Link to post
Share on other sites

11. True - St. John's wort reduces efficacy of OCP by enzyme induction.

Manchester Course

Share this post


Link to post
Share on other sites

All taken from maudsley guidelines book.

8. Caffeine and false positive dexamethasone positive DST.suppression test. -

answer- caffeine can increase cortisol secretion and gives a false positive DST.

uhde et al,1985 archival of j p

9. Caffeine interacts with benzodiazepines.

-high doses can reduce the efficacy of benzodiazepines by reducing receptor binding.

10. Caffeine interacts with clozapine.

clozapine serum levels can be raised by up to 60%, thro competetive inhibition of CYP1A2.

Effects of caffeine withdrawal from the diet on the metabolism of clozapine in schizophrenic patients.

J Clin Psychopharmacol. 1998 Aug;18(4):311-6.

Share this post


Link to post
Share on other sites

1. Aripiprazole is a D2 partial agonist TRUE

2. Aripiprazole is a 5HT2 antagonist TRUE

Ref: internet

Studies suggest that Abilify works differently under different conditions

Functional antagonist activity at D2 receptors in a hyperdopaminergic environment1

Functional agonist activity at D2 receptors in a hypodopaminergic environment1

Abilify has serotonin antagonist activity at 5-HT2A receptors and partial agonist activity at 5-HT1A receptors.

Abilify has moderate affinity for alpha1-adrenergic and histamine (H1) receptors.

Abilify has no appreciable affinity for cholinergic muscarinic receptors.

The mechanism of action of Abilify, as with other drugs having efficacy in schizophrenia, is unknown. However, it has been proposed that the efficacy of Abilify is mediated through a combination of partial agonist activity at dopamine D2 receptors and serotonin 5HT1A receptors, and antagonist activity at serotonin 5HT2A receptors.5 Partial agonism refers to the ability to both block a receptor if it is overstimulated and stimulate a receptor when activity is needed

Share this post


Link to post
Share on other sites

1 & 2 true- thats how it is being marketed!

3)procyclidine long term- no physical dependence mentioned anywhere.

5)seratonin receptor 5HT3 is different na+K ion channels

11)true

Share this post


Link to post
Share on other sites

3. Physical dependence can develop in long term procyclidine use.

FALSE

'Some patients experience a buzz, especially with benzhexol or procyclidine, and develop dependence with desire for higher doses' From USE OF DRUGS IN PSYCHIATRY, Gaskell publications

Share this post


Link to post
Share on other sites

Q3 Can procyclidine cause physical dependance?

True.

'Sudden stoppage can produce acute side effects and may precipitate cholinergic rebound. Post- synaptic cholinergic receptors have become sensitised by long-term muscarinic blockade.' Use of Drugs in Psychiatry. Gaskell

Share this post


Link to post
Share on other sites

1.Higher doses of Fluoxetine are needed in Bulimia Nervosa?

Share this post


Link to post
Share on other sites

2.Acidic urine is good for excretion of trycyclils?

Share this post


Link to post
Share on other sites
Sign in to follow this  
Followers 0