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Part II ISQ Club - Pharmacology

83 posts in this topic

30 Part II ISQs on two topics will be posted twice a week. 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. All ISQs are taken from previous posts by Forum members.

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.

NOTE: NEXT ISQ CLUB POST WILL BE ON 16 FEBRUARY 2004.

1. The half life of drugs is increased in old people

2. Clonazepam causes hallucinations

3. 5HT receptors are both ionotropic and metabotropic

4. The QT interval on an ECG can be a maximum of 400 milliseconds

5. Liver damage may be caused by diazepam

6. Clozapine can be used with Carbamazepine

7. Doxazosin can be used safely with Reboxetine

8. The combined side effects of alcohol and diazepam are mainly pharmacokinetic

9. Cimetidine decreases antidepressant levels

10. 5-HT3 receptors are linked to Na-Ion channels

11. The ratio of cortisol to DHEA is increased in adolescents with depression

12. In pharmacokinetics the area under the curve is greater if the drug elimination is faster

13. Moclobemide does not cause a tyramine reaction

14. Fluoxetine increases levels of diazepam

15. Clozapine, at any clinical dose, induces less akathisia than risperidone

16. Benzodiazepines may increase beta waves on the EEG

17. Reboxetine causes 5-HT2 blockade

18. Barbiturates increase fast activity on the EEG

19. Tricyclic antidepressants can cause peripheral neuropathy

20. Atypical neuroleptics have a longer D2 receptor occupancy than typical neuroleptics

21. Nicotine patches improve concentration in non-smokers

22. Acetylcholinesterase inhibitors lead to cognitive improvement in 60% of cases of mild Alzheimer’s disease

23. Erectile dysfunction is caused by paroxetine

24. Rivastigmine is a selective inhibitor of buterylcholinesterase

25. Mirtazapine blocks H1 receptors

26. Mirtazapine causes indirect 5HT1a stimulation

27. ECT and amitriptyline have synergistic actions

28. Bilateral versus unilateral ECT causes more rapid response in depression

29. ECT causes retrograde amnesia as a side effect

30. Heteroreceptors decrease neurotransmitter release through presynaptic mechanisms

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Question 1.

1. The half life of drugs is increased in old people

True: (Drug treatment in Psychiatry, Silverstone & Turner) There is prolonged elimination half life and renal clearance of drugs in the elderly.

Hepatic Metabolism slowed: ? age-related impairment in hepatic function; ?reduction in liver size; ?decreased live blood flow with incr. age.

Renal clearance: GFR decreases with age.

Some eg of elimination T1/2's which increase: Amitryptaline (Young- under 50's: 22hrs; old 37 hrs) ,CHlordiazopoxide; desipramine; Diazepam, Lorazepam, Zopiclone

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2. 2. Clonazepam causes hallucinations

True:

Side effects of clonzepam are listed here. Hallucinations is a rare side effect of clonazepam.

Symptoms or Effects

Common: Anxiety, behavior problems, insomnia, irritability, drowsiness, or problems with coordination.

Rare: Abdominal cramps, blurred vision, chest congestion, coated tongue, confusion, convulsions, depression, diarrhea, double vision, dry mouth, fever, fluid retention, hair loss, hallucinations, headache, involuntary eye movement, loss of voice, memory loss, racing heartbeat / palpitations, shaking / slurred speech, sore gums, staggering / trembling, trouble breathing, unusual bleeding / bruising, or urination problems.

See physician always: Abdominal cramps, blurred vision, chest congestion, coated tongue, confusion, convulsions, depression, diarrhea, double vision, dry mouth, fever, fluid retention, hair loss, , hallucinations, headache, involuntary eye movement, loss of voice, memory loss, racing heartbeat / palpitations, shaking / slurred speech, sore gums, staggering / trembling, trouble breathing, unusual bleeding / bruising, or urination problems.

http://www.psyweb.com/Drughtm/klonopin.html

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3. 5HT receptors are both ionotropic and metabotropic

True:

5HT3- ionotropic

5HT 1A; 5HT1B; 5HT1D; 5HT4 - G-protein linked to adenylate cyclase (metabotropic)

5HT2A; 5HT2B; 5HT2C: coupled to phosphatidly inositol system.

(Examination notes in psychiatry Mahli and Mitchell: p166)

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4. The QT interval on an ECG can be a maximum of 400 milliseconds

QTc used rather than QT; QTc of greater than 440 is abnormal.

Bazett's formula:

Most studies involving QT interval corrections in the literature use Bazett's formula, defined as the observed QT interval divided by the square root of the R-R interval in seconds. A corrected QT interval of > 440 msec is defined as abnormal.

http://medicine.ucsf.edu/housestaff/ecg/qt.html

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5. Liver damage may be caused by diazepam

True - very rarely described.

BNF mentions Cholestasis;

Anti-anxiety Drugs. Benzodiazepines, such as chlordiazepoxide, diazepam, and flurazepam, have very low hepatotoxic potential, with only case reports in the literature, usually with a cholestatic pattern.39,40

39. Fang M, Ginsberg A, Dobbins W III. Hepatic jaundice associated with flurazepam hydrochloride. Ann Intern Med 1978;89:363-364.

40. Andrade R, Lucena I, Alcantara R, Fraile J. Bentazepam-associated chronic liver disease. Lancet 1994;343:860

http://hepatitis-central.com/hcv/drugs/hepatotoxicity/cause.html

PS - Benzo's can cause fulminant hepatic necrosis in cats 3 to 5 days after treatment.

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6. Clozapine can be used with Carbamazepine

???True: it isn't recommended and although relatively contraindicated it isn't aboslutel - so it may be? (Sorry this is the sort of ISQ that I HATE.... see the 2 references below).

See below:

Avoid concomitant use of drugs with substantial potential for causing agranulocytosis Metabolism of clozapine accelerated (reduced plasma concentration) (BNF online on interactions between clozapine and carbemazipine).

Although concomitant use of CLOZARIL® (clozapine) and carbamazepine is not recommended, it should be noted that discontinuation of concomitant carbamazepine administration may result in an increase in CLOZARIL® (clozapine) plasma levels. http://www.rxlist.com/cgi/generic3/clozapine_ad.htm

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7. Doxazosin can be used safely with Reboxetine

??TRUE: BNF only contraindicates MAOI's with reboxetine.

BJPsych won't let me into correpondance to read below:

Doxazosin for reboxetine-induced urinary hesitancy

E Szabadi

Br J Psychiatry 173: 441b-442b.

NIH web-site supports use of alpha-blockers with reboxetine although didn't mention doxazosin.

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18. Barbiturates increase fast activity on the EEG.

TRUE

Just a guess.

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9. Cimetidine decreases antidepressant levels

False - Increases them: Appendix 1 of BNF says it inhibits metabolism of amitriptylin, doxepin, imipramine, moclobemide, nottriptyline and sertraline - increases plsma concentrations

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10. 5-HT3 receptors are linked to Na-Ion channels

?TRUE

5-HT3 receptors are centrally and peripherally occuring ligand gated , cation selective ,ion channels mediating membrane depolarization and neuronal excitation

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25. Mirtazapine blocks H1 receptors

26. Mirtazapine causes indirect 5HT1a stimulation

both true ,page 2390, comp txtbk of psychiatry, it has low affinity for 5-ht1a and 5-ht1b subtypes but action at the NE nueron causes its release.

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27. ECT and amitriptyline have synergistic actions .false avoid concommitant use as anticholinergic activity may worsen cognitive impairment.page 2514, comp txtbk of psychiatry >:(

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29. ECT causes retrograde amnesia as a side effect .

true, memory loss, a major adverse effect of ECT has both retrograde and anterograde comnponents. page 2513 comp txtbk of psych. :'(

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8) The combined side effects of alcohol and diazepam are mainly pharmacokinetic.

FALSE

The combined side-effects of BDZ's and alcohol (ataxia, incoordination, sedation) are mainly pharmacodynamic, i.e. additive/synergistic.

Alcohol has only a minimal effect on the metabolism of diazepam in a normal, healthy adult.

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13. Moclobemide does not cause a tyramine reaction

FALSE

'Tyramine taken with it can still be metabolised my MAO-B. Also, because of its reversibility, large quantities of tyramine or other substrates will displace moclobemide from the enzyme.'

Use of drugs in psychiatry 5th edn Gaskell

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19. Tricyclic antidepressants can cause peripheral neuropathy

FALSE

check'd BNF, Physician desk reference and online resources. Not mentioned anywhere as S/E

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Q25,26-both true.(ref:psychopharmacology of antidepressants-stahl) ;)

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Q28-true(Ref:Companion)

Q24-false,it is a 'pseudoirreversible' acetylcholinesterase & butylcholinesterase inhibitor(ref;psychotropic drug directory-bazire) :D

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Q4. Rivastigmine is a selective inhibitor of

buterylcholinesterase.

False : It is Acetylcholinesterase inhibiting agent in BNF page 251.

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Q 16 Benzodiazepines may increase beta waves on the EEG

True (Ref Puri and Hall )

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20. False

Shorter occupancy may explain less EPS

Can't remeber where read.

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