Pharmadynamics Flashcards
Which of the following medications has been found to be effective in patients with premature ejaculation?
Select one:
1. Flunarizine
2. Fluoxetine
3. Flupentixol
4. Fluphenazine
5. Trifluoperazine
Fluoxetine
Due to the inhibitory effects of serotonin on the central ejaculatory reflex, selective serotonin reuptake inhibitors (SSRIs) are useful in the treatment of Premature Ejaculation. These inhibitors have been shown to delay ejaculation in multiple placebo-controlled randomized studies (Biri, et al., 1998; Haensel, Klem, Hop, Slob, 1998; Kara et al.,, 1996; Kim and Soo. 1998; Waldinger , Hengeveld, Zwinderman, Olivier, 1994, 1997, 1998) and is the most common class of medications used to treat PE currently.
Drug that is comparatively safe as an adjunctive to MAOI in treating depression is
Select one:
1. Amitriptyline
2. Clomipramine
3. Fluoxetine
4. Lithium
5. Paroxetine
Amitriptyline
MAOIs potentiate the actions of TCAs, which may provide an explanation for the use of such a combination in the treatment of therapy-resistant depression. There is evidence to suggest that a combination of an MAOI with clomipramine is more likely to produce serious adverse effects than occurs with other TCAs.
Buspirone acts on
Select one:
1. GABA-b receptor complex
2. 5HT2a receptor
3. 5HT1a and 5HT2a receptor
4. 5HT1a receptor
5. GABA-a receptor complex
5HT1a receptor
Buspirone acts on 5HT1-a receptors. It is a partial agonist at post-synaptic 5HT1-a receptors and a full agonist at pre-synaptic 5HT1-a receptors.
A patient on mirtazapine treatment develops rapidly spreading bacterial infection. Which of the following must be immediately checked?
Select one:
1. Liver function
2. Differential count
3. Renal function
4. CSF profile
5. Blood glucose
Differential count
Severe neutropenia, defined as less than 0.5 x 10^9/L mature neutrophil cells, is a potentially life-threatening side effect of mirtazapine, occurring with a risk of up to 1 in 1,000 instances.
Which one among the following has high D2/high 5HT2 activity?
Select one:
1. Clozapine
2. Quetiapine
3. Risperidone
4. Haloperidol
5. Amisulpride
Risperidone
Haloperidol has a High D2/low 5HT2 activity. High D2/high 5HT2 activity is characteristic of atypicals such as olanzapine, risperidone and also loxapine. Low D2/high 5HT2 is specific to clozapine while some argue that quetiapine has a lowD2/low 5HT2 activity.
Weight gain caused by clozapine is possibly related to
Select one:
1. Alpha-2 antagonistic activity
2. 5HT1-a receptor antagonistic activity
3. 5HT2-a receptor antagonistic activity
4. 5HT2-c receptor antagonistic activity
5. 5HT3 receptor antagonistic activity
5HT2-c receptor antagonistic activity
The mechanism by which weight gain occurs during treatment with antipsychotics is poorly understood, but
the broader receptor affinities of the agents and their antagonism of histamine H1 and serotonin 5-HT2C
receptors have been implicated.
The enzyme/s that metabolise/s most of the body dopamine:
Select one:
1. MAO-A and COMT
2. COMT only
3. MAO-A and MAO-B
4. MAO-B and COMT
5. MAO-A and Tyrosine hydroxylase
MAO-B and COMT
Dopamine is metabolized in the liver, kidney, and plasma by MAO and COMT. Therefore, inhibition of one or both of these enzymes would decrease dopamine metabolism and result in increased levels of dopamine in the brain.
Mechanism of action of acamprosate is
Select one:
1. Opioid antagonism
2. Glutamate antagonism
3. Inhibits alcohol dehydrogenase
4. Opioid agonism
5. Inhibits aldehyde dehydrogenase
Glutamate antagonism
Acamprosate’s mechanism is not well understood but is thought to involve interference with excitatory amino acids such as glutamate that may be involved in alcoholic relapse.
Which of the following antidementia drugs acts directly on nicotine receptors?
Select one:
1. Donepezil
2. Tacrine
3. Rivastigmine
4. Galantamine
5. Memantine
Galantamine
Galantamine, unlike the other anticholinesterases in clinical use, is derived from the alkaloids from the daffodil and snowdrop family. It is a reversible, competitive inhibitor of acetylcholinesterase with some
inhibitory action on butyrylcholinesterase. It is also an agonist at nicotinic receptor sites. Although a clinically effective drug, galantamine frequently causes gastrointestinal side effects.
Which drug acts as a full agonist at Mu receptor and has a long half-life?
Select one:
1. Acamprosate
2. Buspirone
3. Methadone
4. Buprenorphine
5. Disulfiram
Methadone
Methadone is a full mu- opioid agonist. Its half-life is approximately 24 hours with regular use.
The pharmacological activity of benzodiazepines depends on its action on which of the following receptors?
Select one:
1. Beta Adrenergic receptor complex
2. GABA-a and GABA-b receptor complex
3. 5HT1-A receptor complex
4. GABA-b receptor complex
5. GABA-a receptor complex
GABA-a receptor complex
Benzodiazepines act on GABA-a receptor complex and potentiates GABAergic function.
Which of the following is a noradrenaline reuptake inhibitor?
Select one:
1. Risperidone
2. Reboxetine
3. Agomelatine
4. Fluoxetine
5. Paroxetine
Reboxetine
Reboxetine, the first selective norepinephrine reuptake inhibitor used in the treatment of depression, mainly acts by binding to the norepinephrine transporter and blocking the reuptake of extracellular norepinephrine.
Which of the following is a 5HT1A partial agonist?
Select one:
1. Buspirone
2. Pramipexole
3. Amisulpride
4. Risperidone
5. Aripiprazole
Buspirone
Buspirone is an azaspirodecanedione, a non-benzodiazepine anxiolytic. Buspirone’s mechanism of action is related to 5HT partial agonism.
Which of the following street drugs is called a dissociative anaesthetic?
Select one:
1. Ketamine
2. Cannabis
3. Heroin
4. LSD
5. Cocaine
Ketamine
Ketamine is used as a veterinary anaesthesia and produces a state of dissociative anaesthesia (not same as
psychological dissociation).
How much Zuclopenthixol depot is equivalent to 50mg of haloperidol given every four weeks?
Select one:
1. 200mg every 2-4 weeks
2. 20 mg every 2-4 weeks
3. 20mg every 3 weeks
4. 100mg every 2-4 weeks
5. 400mg every 2 weeks
200mg every 2-4 weeks
Using antipsychotic depot conversion chart from POMH (Prescribing Observatory for Mental Health), 200mg / 2 weeks or 400mg/4 weeks of zuclopentixol depot is equivalent to 50mg of haloperidol depot every 4 weeks.
Disulfiram acts on
Select one:
1. Sigma receptors
2. Alcohol dehydrogenase
3. Glutamate dehydrogenase
4. Aldehyde dehydrogenase
5. Nicotinic cholinergic system
Aldehyde dehydrogenase
In usual doses, disulfiram acts via inhibition of acetaldehyde dehydrogenase that produces deterrent effects when alcohol is consumed (flush reaction).
The endocrine effects of neuroleptics would include all except
Select one:
1. Gynaecomastia
2. Primary amenorrhoea
3. Weight gain
4. Lactorrhoea
5. Impotence
Primary amenorrhoea
The endocrine effects are probably largely due to elevated prolactin, whose release is normally inhibited by dopamine. The endocrine effects would include secondary amenorrhoea and not primary amenorrhoea.
Which of the following drugs is not suitable for treating acute mania?
Select one:
1. Topiramate
2. Lithium
3. Carbamazepine
4. Olanzapine
5. Valproate
Topiramate
Though initial data from open trials suggested that topiramate may possess antimanic properties; this has not been borne out by later more rigorous trials.
The drug alprazolam acts on
Select one:
1. NMDA receptors
2. GABA
3. D1 receptors
4. Histaminergic receptors
5. M1 muscarinic receptors
GABA
Alprazolam is a benzodiazepine; it acts via GABA mechanisms.
Which of the following increases the risk of withdrawal reactions to therapeutic drugs?
Select one:
1. The drug having anticholinergic properties
2. Taking the drug after food
3. Having multiple active metabolites with slow clearance
4. Slow withdrawal of the drug
5. Drugs being a partial agonist instead of full agonist.
The drug having anticholinergic properties
Paroxetine has anticholinergic properties; withdrawal causes cholinergic rebound symptoms.
Which of the following has atypical antipsychotic activity?
Select one:
1. Fluphenazine
2. Promazine
3. Chlorpromazine
4. Amoxapine
5. Amisulpiride
Amisulpiride
Amisulpride has atypical antipsychotic activity as it produces very low EPSEs and is more D2/3 selective compared to other typicals. But it does not have 5HT2A blockade like other newer atypicals.
The mechanism of action of varenicline tartrate is
Select one:
1. Nicotinic antagonist
2. Partial muscarinic agonism
3. Inhibition of nitric oxide synthesis
4. Phosphodiesterase inhibition
5. Partial nicotinic agonism
Partial nicotinic agonism
Varenicline is an a4ß2 nicotinic acetylcholine receptor partial agonist that relieves symptoms of nicotine withdrawal and cigarette craving through its agonist actions while blocking the reinforcing effects of continued nicotine use through an antagonist action.
The mechanism of action for sodium valproate
Select one:
1. Dopamine stabilisation
2. NMDA antagonism
3. Benzodiazepine antagonism
4. GABA potentiation
5. Membrane stabilising
GABA potentiation
Valproate acts at sodium channels, at several important steps in GABA metabolism leading to GABA potentiation, and on the activity of histone deacetylase (which influences gene transcription).
Which of the following statements best describes the receptor profile of trazodone?
Select one:
1. It is a serotonin antagonist
2. It is a mixed serotonin antagonist/agonist.
3. It is a serotonin, dopamine and norepinephrine antagonist
4. It is a serotonin, dopamine and norepinephrine agonist
5. It is a serotonin agonist
It is a mixed serotonin antagonist/agonist
Trazodone is a multifunctional drug: it is a hypnotic at low doses and an antidepressant at high doses due to the manner in which different multifunctional binding properties apply at different doses. Trazodone’s most potent binding property is 5-HT2A antagonism. Its ability to block Serotonin reuptake transporters (SERT) is 100 fold less potent than its ability to block 5- HT2A receptors. Trazadone is categorized as ‘serotonin antagonist-reuptake inhibitor’. At lower doses, it acts as 5HT2A antagonist; though at higher doses it acts as SERT blocker.
Which of the following actions can cause anorgasmia?
Select one:
1. Beta agonism
2. GABA-A agonism
3. Alpha 1 agonism
4. Antihistaminergic property
5. Alpha 1 antagonism
Alpha 1 antagonism
Alpha 1 antagonism, 5HT2A/2C stimulation (delayed ejaculation in SSRIs) can cause anorgasmia. Retrograde ejaculation due to Alpha 1 block, anticholinergic and antihistaminic effects.
Endogenous substrates for monoamine oxidase (MAO) isoenzymes include
Select one:
1. Tyramine, acetylcholine, and dopamine.
2. Acetylcholine, dopamine and epinephrine.
3. Epinephrine, dopamine, and serotonin.
4. Tyramine, serotonin, and histamine.
5. Histamine, acetylcholine, and serotonin.
Epinephrine, dopamine, and serotonin.
Endogenous monoamines serotonin, dopamine and norepinephrine, are broken down by MAO enzymes. MAO-A is more selective for serotonin while MAO-B is more so for dopamine.
Drug X produces improvement in depression when given at a dose of 10mg. Drug Y which acts via the same mechanism as X produces the same improvement when given at a dose of 20mg. When X and Y are given together Y binds to more receptors in a quicker and stronger fashion than X. Which of the following is true?
Select one:
1. Y has lesser affinity then X
2. X is less potent than Y
3. X and Y are equally efficacious
4. X and Y have equal potency but different affinity
5. X and Y have equal affinity but different potency
X and Y are equally efficacious
Efficacy refers to how well the drug produces the expected response i.e. the maximum clinical response produced by a drug (‘productivity’). Efficacy depends on affinity, potency, duration of receptor action in some cases and kinetic properties such as half life, among other factors.
Which one among the following has a stimulant effect?
Select one:
1. Dothiepin
2. Lofepramine
3. Imipramine
4. Amitryptyline
5. Desipramine
Desipramine
Desipramine has relative selectivity for noradrenaline re-uptake and has a stimulant effect.
Which one of the following has antiepileptic activity?
Select one:
1. Fluoxetine
2. Buspirone
3. Buspirone
4. Bupropion
5. Gabapentin
Gabapentin
Gabapentin has antiepileptic property.
Which of the following types of drug molecules mimic endogenous chemical transmission?
Select one:
1. Antagonists
2. Agonists
3. Partial agonists
4. Non-competitive antagonists
5. Irreversible enzyme inducers
Agonists
Most antagonist drugs are competitive in nature, are displaced from their binding site by agonists so that at high doses the agonist can still exert maximum effect and cause a shift to the right in the dose-response curve for the agonist. Agonists are drugs that mimic endogenous transmission. A partial agonist can partially
antagonise the effect of full agonists. Buprenorphine, buspirone and aripiprazole are all partial agonists.
The mechanism of action of cyproheptadine is
Select one:
1. Histamine H1 receptor blockade
2. Serotonin 5HT3 receptor blockade
3. Serotonin 5HT2 receptor stimulation
4. Histamine H2 receptor blockade
5. Histamine H1 receptor stimulation
Histamine H1 receptor blockade
Anorgasmia related to SSRI use may be treated by cyproheptadine one to two hours before sexual activity. Cyproheptadine is a sedating antihistamine with antimuscarinic,5HT2A serotonin-antagonist and calcium-channel blocking properties. It competes for H1-receptor sites on effector cells in the GIT, blood
vessels and respiratory tract.
The chronic administration of tricyclics results in
Select one:
1. Upregulation of beta-adrenergic receptors
2. Down regulation of beta and alpha adrenergic receptors
3. Up-regulation of alpha-adrenergic receptors
4. Downregulation of alpha-adrenergic receptors
5. Downregulation of beta-adrenergic receptors
Downregulation of beta-adrenergic receptors
It has been consistently reported that chronic administration (2 to 4 weeks of treatment) of antidepressant drugs causes a downregulation of beta receptors in rats. However, such effects are not observed after acute or single administration of these drugs. Since most of the antidepressant drugs tested thus far produce such effects, it has been suggested that downregulation or decreased responsiveness of beta-adrenergic receptors may be related to the therapeutic effects manifested by antidepressant drugs. This is yet to be clarified.
Excitotoxicity that is secondary to glutamatergic overstimulation results in neuronal damage. This is the basis of treating patients with neurodegenerative disorders with which of the following medications?
Select one:
1. Selegiline
2. Donepezil
3. Risperidone
4. Galantamine
5. Memantine
Memantine
The hypothesis that glutamate-mediated neurotoxicity is involved in the pathogenesis of AD is increasingly
being favoured; Glutamate receptors are overactive, and N-methyl-D-aspartate (NMDA) receptor antagonists have therapeutic potential for the treatment of AD and other neurological disorders. Memantine is a non-competitive NMDA antagonist that is considered a neuroprotective drug.
Which one among the following is a weak inhibitor of cytochrome P450?
Select one:
1. Both 1 and 2
2. Fluvoxamine
3. Citalopram
4. Paroxetine
5. Fluoxetine
Citalopram
Citalopram and Escitalopram do not produce cytochrome P 450 inhibition. Fluoxetine, Fluvoxamine and Paroxetine are potent inhibitors of several hepatic cytochrome enzymes. Sertraline is safer, while citalopram is the safest. Citalopram is a weak inhibitor of 2D6.
Which one of the following is a pure D2 antagonist?
Select one:
1. Aripiprazole
2. Clozapine
3. Risperidone
4. Amisulpride
5. Sulpiride
Sulpiride
Sulpiride is a pure D2 antagonist. Whereas, Amisulpride is a D2/D3 antagonist. At low doses blocks autoreceptors thus increasing the synaptic dopamine levels and thought to be how it improves negative symptoms. In the limbic region, blockade of postsynaptic D2/D3 receptors reduces positive symptoms.
A patient with Parkinson’s disease experiences visual hallucinations on levodopa/carbidopa therapy. The most appropriate intervention would be to initiate treatment with which of the following medications?
Select one:
1. Aripiprazole
2. Amisulpride
3. Olanzapine
4. Risperidone
5. Quetiapine
Quetiapine
Atypical antipsychotic, especially quetiapine, have a reduced likelihood of causing adverse drug-induced parkinsonism and therefore a possible role in treating psychotic symptoms in patients with Parkinson’s, including the hallucinations induced by levodopa/ carbidopa.
Mechanism of action of buprenorphine is via partial agonism at
Select one:
1. ß-opioid receptors
2. µ-opioid receptors
3. Adrenergic receptors
4. k-opioid receptors
5. Cholinergic receptors
µ-opioid receptors
Buprenorphine. A partial opiate agonist at mu-receptors is available in sublingual form as an alternative to methadone for agonist maintenance treatment of opioid dependence.
Which one of the following has been postulated as the pharmacological basis of clozapine related hypersalivation?
Select one:
1. Reduced cholinesterase activity
2. Activation of the swallowing reflex.
3. Muscarinic M-4 antagonism
4. Adrenergic alpha-2 stimulation
5. Muscarinic M-4 agonism
Muscarinic M-4 agonism
Clozapine is well known to be associated with hypersalivation (drooling particularly at night). This seems to be problematic in the early stages of treatment and is probably dose-related. M4 agonism may be an underlying mechanism though this is not clear. Loss of swallowing reflex may also contribute.
Which of the following has no evidence-based support when prescribing antidementia drug donepezil?
Select one:
1. Reduces caregiver burden
2. Improves the amount of daily activities in some patients
3. Improves neuropsychiatric symptoms
4. Reduces the progression of cognitive decline
5. Reduces time to institutionalisation
Reduces time to institutionalisation
There is strong evidence that donepezil has efficacy against the three major domains of Alzheimer’s disease symptoms, namely functional ability, behaviour, and cognition. The strongest evidence is for improvement or less deterioration in global outcomes and cognition in the short to medium term. There is limited evidence that improved global outcomes are maintained in the long term and clear evidence to support long-term maintenance of cognitive benefits. Also, donepezil appears to maintain function in the long term, and there is some level 1 and two evidence of improved or limited deterioration in behaviour or mood in the short to medium term. Despite donepezil’s effects on major symptoms of Alzheimer’s disease, its impact on patients’ quality of life has not been consistently demonstrated, perhaps reflecting the difficulty of assessing this aspect in this patient population. Donepezil may also lessen caregiver burden. There is limited and conflicting weak evidence that long-term donepezil treatment delays time to institutionalization.
Which of the following is a partial D2 agonist?
Select one:
1. Risperidone
2. Amisulpride
3. Pramipexole
4. Aripiprazole
5. Buspirone
Aripiprazole
Aripiprazole is a dopamine D2 receptor partial agonist with partial agonist activity at serotonin 5HT1A receptors and antagonist activity at 5HT2A receptors.
A new drug A is a non-competitive antagonist at NMDA receptors. If availability of glutamate at the receptor sites is increased experimentally after administering drug A, which of the following can happen?
Select one:
1. Effect of drug A is partially reversed
2. Glutamate levels decrease
3. No change takes place
4. Effect of drug A is reversed fully
5. Effect of drug A increases
Effect of drug A is partially reversed
Non-competitive antagonists alter the receptor site in some way so the effects can be reversed only partially by increasing the dose of the agonist drug. Non-competitive antagonism reduces both the potency and the efficacy of agonists.
A 85-year-old lady with a history of cerebrovascular disease, atrial fibrillation, and prior myocardial infarction presents with moderately severe agitated depression with features of self-neglect. She is taking warfarin, lisinopril, and has been on a maximum dose of venlafaxine for last four weeks with moderate effect. The most appropriate intervention to manage the depression is
Select one:
1. Add a benzodiazepine
2. Prescribe trazodone
3. Add mirtazapine
4. Trial of sertraline after stopping venlafaxine
5. Electro convulsive therapy
Add mirtazapine
Mirtazapine works well in combination with venlafaxine; it will be the ideal choice in the above scenario.
Tyramine gains neuronal access and releases stored catecholamines via which of the following routes?
Select one:
1. GABA
2. NMDA channel
3. Calcium channels
4. Sodium channels
5. Catecholamines reuptake channels
Catecholamines reuptake channels
As with most indirect sympathomimetics, tyramine enters the presynaptic neuron through amine uptake pumps - the channels that are blocked by antidepressants such as TCAs.
The therapeutic effects of conventional antipsychotics is mainly due to
Select one:
1. Blockade of dopamine-2 receptors in the mesocortical pathway
2. Blockade of alpha-1 receptors
3. Blockade of dopamine-2 receptors in the nigrostriatal pathway
4. Blockade of dopamine-2 receptors in the tuberoinfundibular pathway
5. Blockade of dopamine-2 receptors in the mesolimbic pathway
Blockade of dopamine-2 receptors in the mesolimbic pathway.
Blockade of dopamine-2 receptors in the mesolimbic pathway leads to the therapeutic effects. Blockade of dopamine-2 receptors in the mesocortical pathway leads to production or worsening of negative symptoms. Blockade of dopamine-2 receptors in the nigrostriatal pathway leads to EPSEs. Blockade of dopamine-2
receptors in the tuberoinfundibular pathway leads features of hyperprolactinaemia such as galactorrhoea,
sexual dysfunction, gynaecomastia, infertility, amenorrhoea, and possibly accelerated osteoporosis. Blockade of alpha-1 receptors leads to sedation, dizziness, orthostatic hypotension.
Which one among the following is the least sedative of tricyclic antidepressants?
Select one:
1. Dothiepin
2. Nortriptyline
3. Amitryptyline
4. Lofepramine
5. Imipramine
Nortriptyline
Amitryptyline and dothiepin are more sedative, with trimipramine being the most sedative, Imipramine and Lofepramine are less sedative, and Nortriptyline is the least sedative.
A 27-year-old man who is taking mirtazapine for generalized anxiety disorder and major depression
experiences significant sedation at a dosage of 7.5 mg/day. Which neurotransmitter receptor is most likely
being affected?
Select one:
1. Nictonic receptors
2. Histamine Type 1 receptors
3. 5HT Type 2 receptors
4. Muscarinic type 1 receptors
5. 5HT type 3 receptors
5HT Type 2 receptors
Blockade of 5HT2 receptors by mirtazapine helps improving the quality of sleep in depressed patients.
Which of the following groups of medications are associated with bruxism more often than the others listed?
Select one:
1. Stimulants
2. Antidementia drugs
3. Antidepressants
4. Antipsychotics
5. Benzodiazepines
Stimulants
Teeth grinding in children is otherwise known as bruxism. It is associated with ADHD especially when stimulants are sued for its treatment.
Poor response to lithium prophylaxis is predicted by
Select one:
1. classic mania
2. family loading of bipolar spectrum disorders
3. rapid cycling
4. secondary mania
5. obsessional symptoms
Rapid cycling
The phenotype of lithium responders tend to differ from that of other mood stabilisers. Patients with episodic pattern, no comorbidity (especially no panic attacks and substance abuse), significantly higher familial risk of bipolar disorder and absence of rapid cycling pattern are some of the indicators for therapeutic response to lithium.
The mechanism of action of barbiturates is by
Select one:
1. Increasing the frequency of chloride channels opening
2. Increasing the duration of chloride channel opening
3. Closing down the potassium channels
4. Increasing the number of chloride channels
5. Closing down the sodium channels
Increasing the duration of chloride channel opening
Barbiturates act on GABA receptors and serve to increase the duration of chloride channel opening.
Receptor blockade in which dopaminergic pathway results in increased prolactin levels in the body?
Select one:
1. Mesocortical pathway
2. Nigrostriatal pathway
3. Mesolimbic pathway
4. Ultra short ganglionic pathway
5. Tuburoinfundibular pathway.
Tuburoinfundibular pathway.
Blockade of dopamine-2 receptors in the mesolimbic pathway leads to the therapeutic effects. Blockade of dopamine-2 receptors in the mesocortical pathway leads to production or worsening of negative symptoms. Blockade of dopamine-2 receptors in the nigrostriatal pathway leads to EPSEs. Blockade of dopamine-2
receptors in the tuberoinfundibular pathway leads features of hyperprolactinaemia such as galactorrhoea,
sexual dysfunction, gynaecomastia, infertility, amenorrhoea, and possibly accelerated osteoporosis.
