73 Questions
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?
Antidepressants increase the amount of monoamines in the CNS and normalize the density/sensitivity of their receptors.
What is the recommended duration of treatment after recovery from the first episode of depression?
6 months
How do antidepressant drugs counteract the effects of neurotransmitter deficiencies?
By inhibiting MAO effects, blocking reuptake, and regulating receptor sites and breakdown of neurotransmitters.
What is the main characteristic of Tricyclic Antidepressants (TCAs) in terms of their chemical structure?
They have a characteristic three-ring nucleus and are lipophilic in nature.
What is the contradiction highlighted in the text regarding the pharmacological effects of certain drugs on neurotransmitter levels?
Drugs like cocaine can increase neurotransmitter levels but are unable to treat depression effectively.
What are two types of antidepressants mentioned in the text as part of pharmacotherapy?
Tricyclic antidepressants (TCA) and Monoamine oxidase inhibitors (MAOI)
What is the primary means of treating depression with drugs according to the text?
Using agents that alter the concentration of neurotransmitters in the brain.
What is the principal mechanism of action of imipramine?
Blockade of re-uptake of monoamine neurotransmitters noradrenaline and serotonin
Which neurotransmitters are affected by imipramine blockade?
Noradrenaline (NA) and serotonin (5-HT)
What are the CNS pharmacological actions of tricyclic antidepressants (TCAs)?
Mood elevation in depressed patients
Name two TCAs with potent anticholinergic effects.
Amitriptyline and Imipramine
What is a clinical indication for using TCAs in addition to depression?
Neuropathic pain
Which TCA is specifically mentioned for treating Nocturnal Enuresis?
Imipramine
What is a significant adverse effect associated with TCAs?
Postural hypotension
What are the contraindications for using TCAs?
Allergy to any drug in this class, recent myocardial infarction, myelography within 24 hours, concurrent use of MAOIs
What is the primary metabolizing organ for TCAs?
Liver
Why is dialysis ineffective in treating acute TCA intoxications?
High distribution volumes due to wide tissue distribution and high lipophilicity
What is depression?
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.
What is a monoamine oxidase inhibitor (MAOI)?
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.
What is a selective serotonin reuptake inhibitor (SSRI)?
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.
What is a tricyclic antidepressant (TCA)?
A drug that blocks the reuptake of norepinephrine and serotonin; relieves depression and has anticholinergic and sedative effects.
What is tyramine?
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.
How are biogenic amines related to depression?
A deficiency of biogenic amines such as norepinephrine, serotonin, or dopamine in key areas of the brain is thought to result in depression.
What are some common symptoms of depression?
Patients who are depressed may have little energy, sleep disturbances, a lack of appetite, limited libido, and inability to perform activities of daily living.
What effect does tyramine have on the body?
Tyramine causes vasoconstriction and raises blood pressure.
What is the mechanism of action of MAOIs?
MAOIs prevent the breakdown of norepinephrine by inhibiting the enzyme monoamine oxidase.
How do SSRIs relieve depression?
SSRIs specifically block the reuptake of serotonin, increasing its concentration in the synaptic cleft.
What are the contraindications for using tricyclic antidepressants during pregnancy and lactation?
The potential for adverse effects in the fetus and neonate
Why should caution be exercised when prescribing tricyclic antidepressants to patients with preexisting cardiovascular disorders?
Due to the cardiac stimulatory effects of the drug
What is the significance of the black box warning on tricyclic antidepressants?
It brings attention to the risk of Suicidality, especially in children and adolescents.
Why is it important to continue tricyclic antidepressants for a certain duration even after symptoms have remitted?
To prevent recurrence of symptoms
What is the recommended approach when starting tricyclic antidepressants to prevent side effects?
Start with a low dose and gradually increase it
Why is it advised to taper the dose of tricyclic antidepressants over a 2-3 week period when stopping the drug?
To prevent withdrawal symptoms
What are some clinically important drug-drug interactions to consider with tricyclic antidepressants?
Interactions with cimetidine, fluoxetine, ranitidine, oral anticoagulants, sympathomimetics, clonidine, and MAOIs
How long does it typically take for tricyclic antidepressants to show any evident action on depression?
2-3 weeks
What are some conditions that would be exacerbated by the anticholinergic effects of tricyclic antidepressants?
Angle-closure glaucoma, urinary retention, prostate hypertrophy, or GI and GU surgery
Why should caution be used when combining tricyclic antidepressants with MAOIs?
Due to the risk of severe hyperpyretic crisis with severe convulsions, hypertensive episodes, and death
Which receptor blockade by tricyclic antidepressants (TCAs) contributes to dry mouth, tachycardia, and blurred vision as adverse effects?
Histamine H1 receptor
Which TCA is commonly used to treat panic disorder?
Clomipramine
In which type of pain condition are tricyclic antidepressants (TCAs) often used for analgesia?
Neuropathic pain
Which TCA is specifically mentioned for the treatment of nocturnal enuresis?
Imipramine
Which part of the body experiences orthostatic hypotension as a cardiovascular adverse effect of tricyclic antidepressants?
Legs
Which neurotransmitter system is relatively less affected by tricyclic antidepressants compared to others like cocaine?
Dopamine system
Which of the following is NOT an adverse effect associated with tricyclic antidepressants?
Weight gain
Which enzyme plays a significant role in the biotransformation of tricyclic antidepressants in the liver?
CYP450
What is the primary role of biogenic amines like norepinephrine and serotonin in the brain?
Regulate mood and attention
Which of the following is NOT mentioned as a potential cause of depression in the text?
Rapid depletion of neurotransmitters due to low synaptic activity
How do antidepressant drugs used to treat depression counteract neurotransmitter deficiencies?
By regulating receptor sites and increasing neurotransmitter levels in the synaptic cleft
What is the primary function of Tricyclic Antidepressants (TCAs) in treating depression?
Block reuptake of neurotransmitters by releasing nerves
Which theory suggests that depression arises from up-regulation of postsynaptic receptors and alterations in their sensitivity?
Receptor Theory
What is the most effective means of treating depression with drugs according to the text?
Altering the concentration of neurotransmitters in the brain
What is a key reason why pregnancy and lactation are contraindications for tricyclic antidepressants?
Possible adverse effects in the fetus and neonate
Which group of patients should be cautious when using tricyclic antidepressants due to the risk of worsening psychoses or paranoia?
Psychiatric patients
What is the recommended duration of continued tricyclic antidepressant use after the remission of depressive symptoms in the first episode?
6-12 months
Why is it essential to taper the dose gradually over 2-3 weeks when stopping tricyclic antidepressants?
To prevent withdrawal symptoms like nausea and tremors
Which drug should be avoided in combination with tricyclic antidepressants due to the risk of severe hyperpyretic crisis and hypertensive episodes?
Monoamine oxidase inhibitors (MAOIs)
What is a common adverse effect associated with abrupt discontinuation of tricyclic antidepressants?
Nausea
What is the main reason for caution when administering tricyclic antidepressants to patients with preexisting cardiovascular disorders?
Cardiac stimulatory effects of the drug
Why is it advised to administer tricyclic antidepressants regularly and in sufficient doses to achieve the desired effect?
To optimize therapeutic efficacy
What is the black box warning associated with tricyclic antidepressants related to?
Suicidality, especially in children and adolescents
Which neurotransmitters are targeted by tricyclic antidepressants?
Norepinephrine and serotonin
What is the primary mechanism of action of monoamine oxidase inhibitors (MAOIs)?
Preventing monoamine oxidase from breaking down norepinephrine
What risk is associated with ingesting tyramine-rich foods while taking a monoamine oxidase inhibitor (MAOI)?
Severe hypertensive crisis
What distinguishes selective serotonin reuptake inhibitors (SSRIs) from other antidepressants in terms of side effects?
Have no anticholinergic or sympathomimetic adverse effects
What is the role of biogenic amines in the development of depression?
Their deficiency in key brain areas results in depression
How do tricyclic antidepressants relieve depression?
By increasing norepinephrine levels in the synaptic cleft
What happens when monoamine oxidase breaks down norepinephrine?
Decreased synaptic norepinephrine levels
What is the main function of tyramine in the body?
Raises blood pressure through vasoconstriction
What distinguishes tricyclic antidepressants from selective serotonin reuptake inhibitors in terms of side effects?
Are not associated with sympathomimetic effects
What effect does a deficiency of biogenic amines in key brain areas have on mood?
Results in more severe and longer-lasting sadness than warranted
Learn about the principal mechanism of action of imipramine as described by the University of Baghdad College of Medicine for the academic year 2022-2023. Explore how imipramine blocks the re-uptake of monoamine neurotransmitters noradrenaline (NA) and serotonin (5-HT) by competing for binding sites of carrier proteins.
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