University of Baghdad College of Medicine 2022-2023 Imipramine Mechanism of Action
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Questions and Answers

What theory suggests that depression results from a deficiency of biogenic amines in key areas of the brain?

Biogenic Amine Theory of Depression

How do monoamine oxidase (MAO) and rapid firing of neurons contribute to the development of depression?

MAO may break down neurotransmitters for recycling and rapid firing of neurons may lead to their depletion.

Name one type of non-pharmacological treatment for depression mentioned in the text.

Psychotherapy

What is the role of antidepressants in treating depression according to the Receptor theory?

<p>Antidepressants increase the amount of monoamines in the CNS and normalize the density/sensitivity of their receptors.</p> Signup and view all the answers

What is the recommended duration of treatment after recovery from the first episode of depression?

<p>6 months</p> Signup and view all the answers

How do antidepressant drugs counteract the effects of neurotransmitter deficiencies?

<p>By inhibiting MAO effects, blocking reuptake, and regulating receptor sites and breakdown of neurotransmitters.</p> Signup and view all the answers

What is the main characteristic of Tricyclic Antidepressants (TCAs) in terms of their chemical structure?

<p>They have a characteristic three-ring nucleus and are lipophilic in nature.</p> Signup and view all the answers

What is the contradiction highlighted in the text regarding the pharmacological effects of certain drugs on neurotransmitter levels?

<p>Drugs like cocaine can increase neurotransmitter levels but are unable to treat depression effectively.</p> Signup and view all the answers

What are two types of antidepressants mentioned in the text as part of pharmacotherapy?

<p>Tricyclic antidepressants (TCA) and Monoamine oxidase inhibitors (MAOI)</p> Signup and view all the answers

What is the primary means of treating depression with drugs according to the text?

<p>Using agents that alter the concentration of neurotransmitters in the brain.</p> Signup and view all the answers

What is the principal mechanism of action of imipramine?

<p>Blockade of re-uptake of monoamine neurotransmitters noradrenaline and serotonin</p> Signup and view all the answers

Which neurotransmitters are affected by imipramine blockade?

<p>Noradrenaline (NA) and serotonin (5-HT)</p> Signup and view all the answers

What are the CNS pharmacological actions of tricyclic antidepressants (TCAs)?

<p>Mood elevation in depressed patients</p> Signup and view all the answers

Name two TCAs with potent anticholinergic effects.

<p>Amitriptyline and Imipramine</p> Signup and view all the answers

What is a clinical indication for using TCAs in addition to depression?

<p>Neuropathic pain</p> Signup and view all the answers

Which TCA is specifically mentioned for treating Nocturnal Enuresis?

<p>Imipramine</p> Signup and view all the answers

What is a significant adverse effect associated with TCAs?

<p>Postural hypotension</p> Signup and view all the answers

What are the contraindications for using TCAs?

<p>Allergy to any drug in this class, recent myocardial infarction, myelography within 24 hours, concurrent use of MAOIs</p> Signup and view all the answers

What is the primary metabolizing organ for TCAs?

<p>Liver</p> Signup and view all the answers

Why is dialysis ineffective in treating acute TCA intoxications?

<p>High distribution volumes due to wide tissue distribution and high lipophilicity</p> Signup and view all the answers

What is depression?

<p>Affective disorder in which a person experiences sadness that is much more severe and longer lasting than is warranted by the event that seems to have precipitated it, with a more intense mood.</p> Signup and view all the answers

What is a monoamine oxidase inhibitor (MAOI)?

<p>A drug that prevents the enzyme monoamine oxidase from breaking down norepinephrine(NE), leading to increased NE levels in the synaptic cleft; relieves depression and also causes sympathomimetic effects.</p> Signup and view all the answers

What is a selective serotonin reuptake inhibitor (SSRI)?

<p>A drug that specifically blocks the reuptake of serotonin and increases its concentration in the synaptic cleft; relieves depression and is not associated with anticholinergic or sympathomimetic adverse effects.</p> Signup and view all the answers

What is a tricyclic antidepressant (TCA)?

<p>A drug that blocks the reuptake of norepinephrine and serotonin; relieves depression and has anticholinergic and sedative effects.</p> Signup and view all the answers

What is tyramine?

<p>An amine found in food that causes vasoconstriction and raises blood pressure; ingesting foods high in tyramine while taking an MAOI poses the risk of a severe hypertensive crisis.</p> Signup and view all the answers

How are biogenic amines related to depression?

<p>A deficiency of biogenic amines such as norepinephrine, serotonin, or dopamine in key areas of the brain is thought to result in depression.</p> Signup and view all the answers

What are some common symptoms of depression?

<p>Patients who are depressed may have little energy, sleep disturbances, a lack of appetite, limited libido, and inability to perform activities of daily living.</p> Signup and view all the answers

What effect does tyramine have on the body?

<p>Tyramine causes vasoconstriction and raises blood pressure.</p> Signup and view all the answers

What is the mechanism of action of MAOIs?

<p>MAOIs prevent the breakdown of norepinephrine by inhibiting the enzyme monoamine oxidase.</p> Signup and view all the answers

How do SSRIs relieve depression?

<p>SSRIs specifically block the reuptake of serotonin, increasing its concentration in the synaptic cleft.</p> Signup and view all the answers

What are the contraindications for using tricyclic antidepressants during pregnancy and lactation?

<p>The potential for adverse effects in the fetus and neonate</p> Signup and view all the answers

Why should caution be exercised when prescribing tricyclic antidepressants to patients with preexisting cardiovascular disorders?

<p>Due to the cardiac stimulatory effects of the drug</p> Signup and view all the answers

What is the significance of the black box warning on tricyclic antidepressants?

<p>It brings attention to the risk of Suicidality, especially in children and adolescents.</p> Signup and view all the answers

Why is it important to continue tricyclic antidepressants for a certain duration even after symptoms have remitted?

<p>To prevent recurrence of symptoms</p> Signup and view all the answers

What is the recommended approach when starting tricyclic antidepressants to prevent side effects?

<p>Start with a low dose and gradually increase it</p> Signup and view all the answers

Why is it advised to taper the dose of tricyclic antidepressants over a 2-3 week period when stopping the drug?

<p>To prevent withdrawal symptoms</p> Signup and view all the answers

What are some clinically important drug-drug interactions to consider with tricyclic antidepressants?

<p>Interactions with cimetidine, fluoxetine, ranitidine, oral anticoagulants, sympathomimetics, clonidine, and MAOIs</p> Signup and view all the answers

How long does it typically take for tricyclic antidepressants to show any evident action on depression?

<p>2-3 weeks</p> Signup and view all the answers

What are some conditions that would be exacerbated by the anticholinergic effects of tricyclic antidepressants?

<p>Angle-closure glaucoma, urinary retention, prostate hypertrophy, or GI and GU surgery</p> Signup and view all the answers

Why should caution be used when combining tricyclic antidepressants with MAOIs?

<p>Due to the risk of severe hyperpyretic crisis with severe convulsions, hypertensive episodes, and death</p> Signup and view all the answers

Which receptor blockade by tricyclic antidepressants (TCAs) contributes to dry mouth, tachycardia, and blurred vision as adverse effects?

<p>Histamine H1 receptor</p> Signup and view all the answers

Which TCA is commonly used to treat panic disorder?

<p>Clomipramine</p> Signup and view all the answers

In which type of pain condition are tricyclic antidepressants (TCAs) often used for analgesia?

<p>Neuropathic pain</p> Signup and view all the answers

Which TCA is specifically mentioned for the treatment of nocturnal enuresis?

<p>Imipramine</p> Signup and view all the answers

Which part of the body experiences orthostatic hypotension as a cardiovascular adverse effect of tricyclic antidepressants?

<p>Legs</p> Signup and view all the answers

Which neurotransmitter system is relatively less affected by tricyclic antidepressants compared to others like cocaine?

<p>Dopamine system</p> Signup and view all the answers

Which of the following is NOT an adverse effect associated with tricyclic antidepressants?

<p>Weight gain</p> Signup and view all the answers

Which enzyme plays a significant role in the biotransformation of tricyclic antidepressants in the liver?

<p>CYP450</p> Signup and view all the answers

What is the primary role of biogenic amines like norepinephrine and serotonin in the brain?

<p>Regulate mood and attention</p> Signup and view all the answers

Which of the following is NOT mentioned as a potential cause of depression in the text?

<p>Rapid depletion of neurotransmitters due to low synaptic activity</p> Signup and view all the answers

How do antidepressant drugs used to treat depression counteract neurotransmitter deficiencies?

<p>By regulating receptor sites and increasing neurotransmitter levels in the synaptic cleft</p> Signup and view all the answers

What is the primary function of Tricyclic Antidepressants (TCAs) in treating depression?

<p>Block reuptake of neurotransmitters by releasing nerves</p> Signup and view all the answers

Which theory suggests that depression arises from up-regulation of postsynaptic receptors and alterations in their sensitivity?

<p>Receptor Theory</p> Signup and view all the answers

What is the most effective means of treating depression with drugs according to the text?

<p>Altering the concentration of neurotransmitters in the brain</p> Signup and view all the answers

What is a key reason why pregnancy and lactation are contraindications for tricyclic antidepressants?

<p>Possible adverse effects in the fetus and neonate</p> Signup and view all the answers

Which group of patients should be cautious when using tricyclic antidepressants due to the risk of worsening psychoses or paranoia?

<p>Psychiatric patients</p> Signup and view all the answers

What is the recommended duration of continued tricyclic antidepressant use after the remission of depressive symptoms in the first episode?

<p>6-12 months</p> Signup and view all the answers

Why is it essential to taper the dose gradually over 2-3 weeks when stopping tricyclic antidepressants?

<p>To prevent withdrawal symptoms like nausea and tremors</p> Signup and view all the answers

Which drug should be avoided in combination with tricyclic antidepressants due to the risk of severe hyperpyretic crisis and hypertensive episodes?

<p>Monoamine oxidase inhibitors (MAOIs)</p> Signup and view all the answers

What is a common adverse effect associated with abrupt discontinuation of tricyclic antidepressants?

<p>Nausea</p> Signup and view all the answers

What is the main reason for caution when administering tricyclic antidepressants to patients with preexisting cardiovascular disorders?

<p>Cardiac stimulatory effects of the drug</p> Signup and view all the answers

Why is it advised to administer tricyclic antidepressants regularly and in sufficient doses to achieve the desired effect?

<p>To optimize therapeutic efficacy</p> Signup and view all the answers

What is the black box warning associated with tricyclic antidepressants related to?

<p>Suicidality, especially in children and adolescents</p> Signup and view all the answers

Which neurotransmitters are targeted by tricyclic antidepressants?

<p>Norepinephrine and serotonin</p> Signup and view all the answers

What is the primary mechanism of action of monoamine oxidase inhibitors (MAOIs)?

<p>Preventing monoamine oxidase from breaking down norepinephrine</p> Signup and view all the answers

What risk is associated with ingesting tyramine-rich foods while taking a monoamine oxidase inhibitor (MAOI)?

<p>Severe hypertensive crisis</p> Signup and view all the answers

What distinguishes selective serotonin reuptake inhibitors (SSRIs) from other antidepressants in terms of side effects?

<p>Have no anticholinergic or sympathomimetic adverse effects</p> Signup and view all the answers

What is the role of biogenic amines in the development of depression?

<p>Their deficiency in key brain areas results in depression</p> Signup and view all the answers

How do tricyclic antidepressants relieve depression?

<p>By increasing norepinephrine levels in the synaptic cleft</p> Signup and view all the answers

What happens when monoamine oxidase breaks down norepinephrine?

<p>Decreased synaptic norepinephrine levels</p> Signup and view all the answers

What is the main function of tyramine in the body?

<p>Raises blood pressure through vasoconstriction</p> Signup and view all the answers

What distinguishes tricyclic antidepressants from selective serotonin reuptake inhibitors in terms of side effects?

<p>Are not associated with sympathomimetic effects</p> Signup and view all the answers

What effect does a deficiency of biogenic amines in key brain areas have on mood?

<p>Results in more severe and longer-lasting sadness than warranted</p> Signup and view all the answers

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