Drugs in Psychiatric Disorders Practice Questions

Q: Which class of drugs is commonly used to treat anxiety by enhancing the effects of GABA?

Benzodiazepines. ***Benzodiazepines*** - **Benzodiazepines** act as positive **allosteric modulators** of the **GABA-A receptor**, increasing the frequency of **chloride channel opening**. - This enhanced **GABAergic transmission** leads to a **hyperpolarization** of neurons, resulting in reduced neuronal excitability, which exerts **anxiolytic**, sedative, and muscle relaxant effects. *Selective serotonin reuptake inhibitors* - **SSRIs** primarily increase the concentration of **serotonin** in the **synaptic cleft** by inhibiting its reuptake, rather than directly acting on GABA. - While effective for anxiety, their mechanism of action is distinct from GABA potentiation, and their therapeutic effects typically have a **delayed onset**. *Tricyclic antidepressants* - **TCAs** primarily inhibit the **reuptake of norepinephrine** and **serotonin**, and also block various receptors like **histaminic**, **cholinergic**, and **adrenergic receptors**. - They do not directly enhance **GABAergic activity**, and their use can be limited by a wide range of side effects due to their broad receptor blockade. *Monoamine oxidase inhibitors* - **MAOIs** prevent the enzymatic degradation of **norepinephrine**, **serotonin**, and **dopamine** by inhibiting the enzyme **monoamine oxidase**, thereby increasing their synaptic concentrations. - Their mechanism is focused on **monoamine neurotransmitters**, and they do not directly modulate **GABAergic transmission**.

Q: A patient being treated with an antipsychotic drug develops tardive dyskinesia. Which class of antipsychotic drugs is most commonly associated with this condition?

Typical antipsychotics. ***Typical antipsychotics*** - **First-generation antipsychotics**, also known as typical antipsychotics, are commonly associated with **tardive dyskinesia** due to their strong **D2 dopamine receptor blockade**. - Prolonged use leads to postsynaptic dopamine receptor hypersensitivity, resulting in involuntary movements. *Atypical antipsychotics* - **Second-generation antipsychotics** (atypical) have a **lower risk** of tardive dyskinesia due to their weaker D2 blockade and strong 5-HT2A serotonin receptor antagonism. - While the risk is present, it is significantly less compared to typical antipsychotics. *Dopamine partial agonists* - Drugs like **aripiprazole** (a dopamine partial agonist) have an even **lower risk of dyskinesia** because they modulate dopamine activity rather than completely blocking it. - They act as functional antagonists in areas with high dopamine and functional agonists in areas with low dopamine. *Anticholinergic drugs* - **Anticholinergic drugs** are sometimes used to treat **acute extrapyramidal symptoms** (like parkinsonism) caused by antipsychotics, but they do not cause or prevent tardive dyskinesia. - In some cases, discontinuing anticholinergics can unmask or worsen tardive dyskinesia.

Q: A 30-year-old man presents with symptoms of depression. He is prescribed a selective serotonin reuptake inhibitor (SSRI). Which of the following drugs is he most likely taking?

Fluoxetine. ***Fluoxetine*** - **Fluoxetine** is a prototypical **selective serotonin reuptake inhibitor (SSRI)**, commonly prescribed for depression. - SSRIs function by **blocking the reuptake of serotonin** in the presynaptic neuron, increasing its concentration in the synaptic cleft. *Amitriptyline* - **Amitriptyline** is a **tricyclic antidepressant (TCA)**, not an SSRI. - TCAs have a broader spectrum of action, blocking the reuptake of both **serotonin and norepinephrine**, and also affecting other receptors (e.g., muscarinic acetylcholine, histamine H1), leading to more side effects. *Venlafaxine* - **Venlafaxine** is a **serotonin-norepinephrine reuptake inhibitor (SNRI)**, not an SSRI. - SNRIs block the reuptake of both **serotonin and norepinephrine**, providing a dual mechanism of action that can be effective for some forms of depression or anxiety. *Mirtazapine* - **Mirtazapine** is an **atypical antidepressant** that primarily acts as an **alpha-2 adrenergic receptor antagonist**, which enhances noradrenergic and serotonergic transmission. - It also blocks 5-HT2 and 5-HT3 serotonin receptors and H1 histamine receptors, which contributes to its unique side effect profile (e.g., sedation, increased appetite).

Q: What is the most common electrolyte imbalance associated with lithium treatment?

Hypercalcemia (high calcium levels). ***Hypercalcemia (high calcium levels)*** - **Hypercalcemia** is the most commonly reported electrolyte abnormality with chronic lithium therapy, occurring in **10-15% of patients**. - Lithium can cause **hyperparathyroidism** by affecting parathyroid gland function, leading to increased PTH secretion and subsequent elevation of serum calcium levels [2]. - This effect can develop after **months to years** of lithium treatment and may persist even after lithium discontinuation. - Regular monitoring of serum calcium and PTH levels is recommended during long-term lithium therapy. *Hypernatremia (high sodium levels)* - **Hypernatremia** is not a direct or common electrolyte imbalance from lithium itself. - While lithium can cause **nephrogenic diabetes insipidus (NDI)** leading to polyuria and polydipsia, patients typically maintain normal sodium levels if they have adequate water access [1], [3]. - Hypernatremia may occur as a **secondary complication** if patients with lithium-induced NDI become dehydrated, but this is not the primary electrolyte abnormality. *Hyperkalemia (high potassium levels)* - **Hyperkalemia** is not typically associated with lithium treatment. - Lithium's effects on renal function do not consistently lead to significant alterations in potassium homeostasis. *Hypokalemia (low potassium levels)* - **Hypokalemia** is not a characteristic electrolyte imbalance with lithium therapy. - Lithium primarily affects water handling and calcium metabolism rather than potassium balance.

Q: Which of the following conditions is NOT a contraindication for the use of Tricyclic Antidepressants (TCAs)?

Impaired renal function. ***Impaired renal function*** - While **Tricyclic Antidepressants (TCAs)** are metabolized in the liver and excreted by the kidneys, **impaired renal function** alone is generally not considered an absolute contraindication but necessitates **dose adjustments** and careful monitoring. - The primary concern with renal impairment is the **accumulation of active metabolites**, which can increase the risk of side effects, but it doesn't preclude their use entirely. *Narrow angle glaucoma* - TCAs have **anticholinergic properties** that can cause mydriasis (pupil dilation), which can precipitate an acute attack in individuals with **narrow-angle glaucoma**. - This is an important contraindication due to the risk of **irreversible vision loss**. *Prostate hypertrophy* - The **anticholinergic effects** of TCAs can worsen urinary retention in patients with **prostate hypertrophy** by relaxing the detrusor muscle and contracting the bladder sphincter. - This can lead to increased discomfort and potentially acute urinary retention. *A patient on MAO inhibitors* - Concomitant use of TCAs with **MAO inhibitors** is an absolute contraindication due to the risk of **hypertensive crisis** and **hyperpyrexia** from potentiation of noradrenergic effects. - This dangerous interaction can lead to severe and potentially fatal symptoms such as hyperthermia, severe hypertension, seizures, and cardiovascular collapse. A washout period of at least 2 weeks is required when switching between these medications.

Q: Which of the following is a side effect of quetiapine?

Dry mouth. ***Dry mouth*** - **Quetiapine** is an atypical antipsychotic that commonly causes **anticholinergic side effects**, including **dry mouth (xerostomia)**. - This symptom results from the drug's antagonistic activity at **muscarinic acetylcholine receptors**. - Dry mouth is a **frequent and well-recognized side effect** occurring in a significant proportion of patients, making it the best answer among the options provided. *Sudden cardiac death* - Quetiapine can cause **QT interval prolongation**, particularly at higher doses or in susceptible individuals, which may increase the risk of **fatal cardiac arrhythmias**. - However, sudden cardiac death is a **rare but serious adverse event**, not a common side effect seen in routine clinical practice. - While this is a documented risk requiring monitoring, **dry mouth is far more frequently encountered** in patients taking quetiapine. *Dyspepsia* - **Dyspepsia (indigestion)** can occur with various medications, but it is not a particularly prominent or characteristic side effect of **quetiapine**. - The more notable side effects of quetiapine include **sedation, weight gain, metabolic effects, and anticholinergic symptoms** rather than gastrointestinal upset. *Hair loss* - **Hair loss (alopecia)** is not a recognized or documented side effect of **quetiapine**. - This is not typically associated with atypical antipsychotics and would not be expected with quetiapine therapy.

Q: Oculogyric crisis is known to be produced by all of the following drugs except:

Atropine. ***Atropine*** - **Atropine** is an **anticholinergic drug** that primarily causes mydriasis (pupil dilation) and cycloplegia (paralysis of ciliary muscle), but it is not known to cause oculogyric crisis. - Oculogyric crisis is a form of **acute dystonia**, which is typically associated with dopamine antagonists. *Prochlorperazine* - **Prochlorperazine** is a **dopamine receptor antagonist** and a typical antipsychotic, commonly used as an antiemetic. - It is known to produce **extrapyramidal symptoms**, including **acute dystonias** like oculogyric crisis, due to its dopamine-blocking effects. *Perphenazine* - **Perphenazine** is a **first-generation (typical) antipsychotic** with potent dopamine-blocking activity. - Similar to other typical antipsychotics, it can cause **extrapyramidal side effects**, including **oculogyric crisis**. *Trifluoperazine* - **Trifluoperazine** is a **high-potency typical antipsychotic** that strongly blocks dopamine D2 receptors. - Its strong dopamine antagonism makes it highly prone to causing **extrapyramidal symptoms**, such as **acute dystonias** like oculogyric crisis.

Q: What is the mechanism of action of tianeptine?

AMPA receptor potentiation. ***AMPA receptor potentiation*** - Tianeptine has been shown to modulate **glutamatergic activity** by potentiating **AMPA receptor function**, promoting neuroplasticity [1]. - This effect is thought to contribute to its **antidepressant and anxiolytic properties**, particularly in stress-related neuronal changes [1]. *Mu-opioid receptor agonism* - While tianeptine does exhibit some weak **mu-opioid receptor agonist activity** at higher doses, it is not considered its primary therapeutic mechanism for antidepressant effects. - The opioid effects are usually associated with its **abuse potential** and are distinct from its primary antidepressant action. *Serotonin reuptake enhancement* - Tianeptine is unique among antidepressants for its property of **enhancing serotonin reuptake**, rather than inhibiting it. - Although it increases serotonin reuptake, this effect alone does not fully explain its antidepressant action, and its **glutamatergic modulation** is considered more critical. *NMDA receptor antagonism* - **NMDA receptor antagonism** is associated with drugs like ketamine, which have rapid antidepressant effects by blocking the receptor [2]. - Tianeptine does not directly act as an NMDA receptor antagonist; instead, it influences synaptic plasticity through **AMPA receptor modulation**.

Q: What condition results from the increased sensitivity of dopamine receptors following chronic dopamine receptor blockade?

Dyskinesia. ***Tardive Dyskinesia*** - **Chronic dopamine receptor blockade**, often observed with long-term use of **antipsychotics**, leads to an **upregulation** of dopamine receptors. - This **increased sensitivity** to dopamine can result in **involuntary movements** such as **tardive dyskinesia** when dopamine levels fluctuate or the blockade is partially overcome. *Hyperphagia* - This refers to abnormally **increased appetite or consumption of food**, which is a general symptom and not specifically linked to the mechanism described. - While some medications affecting dopamine can influence appetite, **hyperphagia** is not the direct result of increased dopamine receptor sensitivity post-blockade. *Hyperpathia* - This describes an **abnormally painful reaction to a stimulus**, especially a repetitive one, and an elevated pain threshold. - It is a **neuropathic pain syndrome** and is not directly related to changes in dopamine receptor sensitivity. *Hypomania* - Hypomania is a **mood state** characterized by persistent elevated, expansive, or irritable mood, and increased activity or energy, less severe than mania. - While dopamine pathways are involved in mood regulation, **hypomania** is not a direct consequence of increased sensitivity of dopamine receptors following chronic blockade.

Question 1

Which class of drugs is commonly used to treat anxiety by enhancing the effects of GABA?

Accepted Answer

Benzodiazepines

Answer

Selective serotonin reuptake inhibitors

Answer

Tricyclic antidepressants

Answer

Monoamine oxidase inhibitors

Question 2

A patient being treated with an antipsychotic drug develops tardive dyskinesia. Which class of antipsychotic drugs is most commonly associated with this condition?

Accepted Answer

Typical antipsychotics

Answer

Dopamine partial agonists

Answer

Anticholinergic drugs

Answer

Atypical antipsychotics

Question 3

A 30-year-old man presents with symptoms of depression. He is prescribed a selective serotonin reuptake inhibitor (SSRI). Which of the following drugs is he most likely taking?

Accepted Answer

Fluoxetine

Answer

Amitriptyline

Answer

Venlafaxine

Answer

Mirtazapine

Question 4

What is the most common electrolyte imbalance associated with lithium treatment?

Accepted Answer

Hypercalcemia (high calcium levels)

Answer

Hyperkalemia (high potassium levels)

Answer

Hypokalemia (low potassium levels)

Answer

Hypernatremia (high sodium levels)

Question 5

Which of the following conditions is NOT a contraindication for the use of Tricyclic Antidepressants (TCAs)?

Accepted Answer

Impaired renal function

Answer

Narrow angle glaucoma

Answer

Prostate hypertrophy

Answer

A patient on MAO inhibitors

Question 6

Which of the following is a side effect of quetiapine?

Accepted Answer

Dry mouth

Answer

Sudden cardiac death

Answer

Dyspepsia

Answer

Hair loss

Question 7

Oculogyric crisis is known to be produced by all of the following drugs except:

Accepted Answer

Atropine

Answer

Perphenazine

Answer

Prochlorperazine

Answer

Trifluoperazine

Question 8

Which of the following is true about ziprasidone?

Accepted Answer

Lower risk of extrapyramidal symptoms compared to typical antipsychotics

Answer

Has anti-depressant properties

Answer

Not safe in cardiac patients due to QT prolongation risk

Answer

Commonly causes significant weight gain

Question 9

What is the mechanism of action of tianeptine?

Accepted Answer

AMPA receptor potentiation

Answer

NMDA receptor antagonism

Answer

Serotonin reuptake enhancement

Answer

Mu-opioid receptor agonism

Question 10

What condition results from the increased sensitivity of dopamine receptors following chronic dopamine receptor blockade?

Accepted Answer

Dyskinesia

Answer

Hyperphagia

Answer

Hyperpathia

Answer

Hypomania

Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders — MCQs

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