Question 51#

Which of the following is potentially antagonistic at dopamine receptors?

A. Imipramine

C. Amoxapine is a TCA with fairly selective inhibition of noradrenaline reuptake. It also has D2 antagonist property. This pharmacological profi le suggests a good option for the treatment of psychotic depression. But in addition to the side-effects of TCA, there is also an additional risk of side-effects associated with D2 antagonism.

Reference:

1. Gelder MG et al., eds. Shorter Oxford Textbook of Psychiatry, 5th edn. Oxford University Press, 2006, p. 542.

Question 52#

Which of the following tricyclic antidepressants is the preferred drug compared to the others listed when prescribed to a patient with cardiovascular illness?

A. Imipramine

C. Cardiovascular side-effects of tricyclics include hypotension and tachycardia. Conduction abnormalities, ECG changes, ventricular arrhythmias, and heart blocks are complications seen especially in people with pre-existing heart disease. Lofepramine is a tertiary amine which is metabolized to desipramine, a secondary amine. Inspite of being a tertiary amine, lofepramine is more selective for norepinephrine reuptake inhibition. It has a better side-effect profile compared to other TCAs. It is also less cardiotoxic than other TCAs.

Reference:

1. Gelder MG et al., eds. Shorter Oxford Textbook of Psychiatry, 5th edn. Oxford University Press, 2006, p. 543.

Question 53#

Which of the following is more common with SSRIs compared to TCAs?

A. Switch to mania

C. SSRIs are safer than TCAs as far as cardiotoxicity, switch to mania, and seizures are concerned. But SSRIs are more prone to cause extrapyramidal reaction, possibly due to an increase in serotonin at 5HT heteroceptors on dopaminergic neurones. Some of the SSRIs may also have a low degree of intrinsic antagonistic action at the dopaminergic receptors.

Reference:

1. Gelder MG et al., eds. Shorter Oxford Textbook of Psychiatry, 5th edn. Oxford University Press, 2006, p. 546.

Question 54#

Serotonin syndrome is possible when SSRIs are combined with which of the following? 

A. Lithium

E. Serotonin syndrome is a potentially fatal syndrome occurring in the context of initiation or dose increase of a serotonergic agent. This syndrome is characterized by altered mental state, agitation, tremor, shivering, diarrhoea, hyper-reflexia, myoclonus, ataxia, and hyperthermia. It could also occur during combination antidepressant therapy. These include medications that exert their primary action through the serotonin receptor (SSRI, SNRI, buspirone, etc), MAOIs, and serotonin precursor tryptophan. Serotonin toxicity is also reported to occur when SSRIs are combined with medications whose mode of action is not known (lithium) or medications which may inhibit CYP enzymes and increase SSRI levels in plasma. Sternbach’s criteria are used to diagnose serotonin syndrome.

Reference:

1. Semple DM et al., eds. Oxford Handbook of Psychiatry, 1st edn. Oxford University Press, 2005, p. 870.

Question 55#

In a patient with depression, an SSRI would be the drug of choice, EXCEPT when:

A. The patient has concomitant cardiac disease

B. SSRIs are generally not sedating. Sometimes they can be activating, producing initial insomnia, anxiety, or panic attacks. They are relatively safer in overdose compared to TCAs. Apart from paroxetine and to some extent fluoxetine, most SSRIs have almost absent anticholinergic activity. SSRIs have been found to be more useful in obsessions than the other antidepressant groups.

Reference:

1. Semple DM et al., eds. Oxford Handbook of Psychiatry, 1st edn. Oxford University Press, 2005, p. 358.