Pharmacology of drugs

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Questions and Answers

What is one effect of tyramine related to the sympathetic nervous system?

Increased sympathetic activity (correct)

Increased gut motility

Reduced energy expenditure

Decreased heart rate

Which neurotransmitter levels can be increased by tyramine?

GABA and acetylcholine

Histamine and phenylethylamine

Epinephrine and norepinephrine

Serotonin and dopamine (correct)

What mechanism does pseudoephedrine use to function as a nasal decongestant?

Directly blocks histamine receptors

Inhibits muscle contraction in the respiratory tract

Increased gut motility

Constricts the arteries in the nasal mucosa (correct)

How does tyramine indirectly increase norepinephrine concentration in the junction?

By displacing NA into the cytosol Signup and view all the answers

What is the role of MAO in relation to tyramine?

It metabolizes tyramine. Signup and view all the answers

What effect does increased norepinephrine in the junction have?

Activation of post-junctional adrenoceptors Signup and view all the answers

What effect does tyramine have on heart rate?

Increases heart rate Signup and view all the answers

Which mechanism is NOT a function of tyramine?

Decreased energy expenditure Signup and view all the answers

What is the primary action of Glyceryl Trinitrate (GTN) in the treatment of angina pectoris?

Increases cGMP levels in vascular muscle Signup and view all the answers

Which of the following side effects is commonly associated with the use of GLP1 agonists like Liraglutide?

Diarrhoea Signup and view all the answers

What is the mechanism of action for Glyceryl Trinitrate after its conversion to nitric oxide?

Causes venodilatation Signup and view all the answers

After sublingual administration, why is Glyceryl Trinitrate used in treating angina pectoris?

It prevents hepatic first-pass metabolism Signup and view all the answers

Which condition is an indication for treatment with Liraglutide?

Obesity Signup and view all the answers

What is a rare but serious side effect associated with GLP1 agonists like Liraglutide?

Pancreatitis Signup and view all the answers

What type of receptors do GLP1 agonists bind to on the vagus nerve?

GLP1 receptors Signup and view all the answers

Which of the following is not a common side effect of using Glyceryl Trinitrate?

Diarrhoea Signup and view all the answers

What is the primary action of H2 receptor antagonists like Cimetidine?

Blocking the binding of histamine Signup and view all the answers

Which condition is particularly treated with Famotidine?

Peptic ulcer disease Signup and view all the answers

What significant interaction is associated with Cimetidine?

Delays clearance of drugs metabolized by CYP450 Signup and view all the answers

Which of the following describes a characteristic of the proton pump inhibitor Omeprazole?

Requires an acidic environment to activate Signup and view all the answers

What is a potential effect of drug accumulation due to Cimetidine's action on CYP450?

Increased blood pressure levels Signup and view all the answers

What is the mechanism of action of Famotidine as an antihistamine?

Competing for binding at H2 receptors Signup and view all the answers

Which is a common therapeutic use for the class of drugs that includes Cimetidine and Famotidine?

Managing acid-related conditions Signup and view all the answers

What type of inhibitor is Cimetidine classified as in relation to the CYP450 enzyme?

Non-selective inhibitor Signup and view all the answers

What is the primary function of Isoprenaline?

Increase heart rate Signup and view all the answers

Which drug is a partial agonist at β-2 receptors?

Terbutaline Signup and view all the answers

What is a common side effect of Salbutamol?

Muscle tremors Signup and view all the answers

What distinguishes Salmeterol from other β-2 agonists?

It's a long-acting agent Signup and view all the answers

What is the role of inhaled corticosteroids in asthma treatment with β-2 agonists?

They enhance the effect of β-2 agonists Signup and view all the answers

Which of the following is a side effect associated with LABAs like Formoterol?

Headaches Signup and view all the answers

Which drug is indicated for acute treatment of bronchoconstriction?

Salbutamol Signup and view all the answers

What outcome is a potential consequence of using β-2 agonists like Terbutaline?

Vasodilation leading to hypotension Signup and view all the answers

What is the primary action of biguanides in managing Type II Diabetes?

Increase insulin mediated glucose uptake Signup and view all the answers

Which of the following is a common side effect of sulfonylureas?

Hypoglycemia Signup and view all the answers

What is the function of SGLT-2 inhibitors in diabetes treatment?

Increase glucose excretion through urine Signup and view all the answers

Which medication might lead to a decrease in glucose synthesis in the liver?

Exogenous insulin Signup and view all the answers

What is the mechanism of action for α-glucosidase inhibitors?

Delay carbohydrate absorption in the intestine Signup and view all the answers

Which side effect is commonly associated with the use of SGLT-2 inhibitors?

Thrush Signup and view all the answers

What is the primary concern when prescribing sulfonylureas to patients?

Risk of renal impairment Signup and view all the answers

Which neuro-psychiatric medication is associated with ADHD treatment and primarily blocks reuptake of dopamine?

Methylphenidate Signup and view all the answers

What action does dopamine reuptake inhibitor medication primarily enhance?

Increase synaptic concentrations of dopamine Signup and view all the answers

What is a contraindication for using α-glucosidase inhibitors?

Inflammatory bowel disease Signup and view all the answers

How is exogenous insulin primarily metabolized in the body?

Mainly in the liver Signup and view all the answers

Which medication is primarily indicated for the treatment of depression?

Reboxetine Signup and view all the answers

What effect does modafinil have that makes it useful in learning disorders?

Enhances wakefulness Signup and view all the answers

What is the primary mechanism of Glyceryl Trinitrate (GTN) in vascular smooth muscle?

Activation of guanylate cyclase Signup and view all the answers

What is a common side effect associated with the use of GLP1 agonists like Liraglutide?

Nausea and vomiting Signup and view all the answers

How does Glyceryl Trinitrate (GTN) primarily affect oxygen demand in the heart?

By causing venodilatation Signup and view all the answers

Which effect is most likely to be a result of sublingual administration of GTN?

Rapid onset of action Signup and view all the answers

What physiological response is primarily induced by glucagon-like peptide 1 (GLP1)?

Enhanced insulin secretion Signup and view all the answers

What potential severe side effect is associated with GLP1 agonists like Liraglutide?

Pancreatitis Signup and view all the answers

What is the primary route of administration for Liraglutide?

Subcutaneous injection Signup and view all the answers

What effect does increased cGMP have in vascular smooth muscle cells?

Vasodilation Signup and view all the answers

What is the primary action of H2 receptor antagonists such as Cimetidine?

Block histamine binding on gastric parietal cells Signup and view all the answers

Which drug is specifically mentioned as requiring an acidic environment to activate?

Omeprazole Signup and view all the answers

What significant drug interaction is associated with Cimetidine?

Inhibition of CYP450 activity Signup and view all the answers

For which condition is Famotidine primarily used?

Gastroesophageal reflux disease (GORD) Signup and view all the answers

What effect does Cimetidine have on blood pressure levels?

Increases blood pressure levels Signup and view all the answers

What is one of the primary therapeutic uses of proton pump inhibitors like Omeprazole?

Reduction of gastric acid secretion Signup and view all the answers

Which of the following statements is true regarding Famotidine?

It selectively inhibits the H2 receptor Signup and view all the answers

What is a characteristic mechanism of action of Cimetidine and similar drugs?

They competitively bind to H2 receptors Signup and view all the answers

What is a potential side effect of dopamine agonists like Bromocriptine?

Visual hallucinations Signup and view all the answers

Which of the following accurately describes the effect of L-DOPA compared to Bromocriptine?

L-DOPA is more targeted towards dopaminergic neurons. Signup and view all the answers

Which mechanism is primarily responsible for the negative side effects associated with prolonged use of dopamine agonists?

Degeneration of dopaminergic nerves Signup and view all the answers

Which condition is primarily treated by dopamine agonists such as Cabergoline?

Parkinson's disease Signup and view all the answers

What is a consequence of the use of dopamine agonists in relation to mood?

Increased anxiety and mood swings Signup and view all the answers

Which neurotransmitter's synthesis is significantly altered by dopaminergic drugs?

Dopamine Signup and view all the answers

What is a distinguishing feature of how dopaminergic agonists work compared to L-DOPA?

Dopaminergic agonists target a wider range of receptors. Signup and view all the answers

What is a noted effect on the effectiveness of dopamine treatments over time?

Effectiveness decreases due to degeneration of dopaminergic nerves. Signup and view all the answers

What effect does the inhibition of angiotensin II have on vascular resistance?

Decreases total peripheral resistance Signup and view all the answers

Which of the following is a potential side effect of medications that inhibit angiotensin II?

Hyperkalaemia Signup and view all the answers

What is a common adverse effect of calcium channel antagonists?

Initial reflex tachycardia Signup and view all the answers

How does the inhibition of aldosterone secretion by angiotensin II inhibitors affect sodium and water retention?

Decreases sodium and water retention Signup and view all the answers

What condition is NOT considered safe for patients taking angiotensin II inhibitors?

Acute renal failure Signup and view all the answers

What is the primary action of dihydropyridine calcium channel antagonists like Nifedipine?

Prevent opening of calcium channels Signup and view all the answers

Which statement reflects a more significant effect of angiotensin II on the cardiovascular system?

Promotes greater vascular remodeling Signup and view all the answers

In which situation would the use of calcium channel blockers be contraindicated?

Bradycardia Signup and view all the answers

What is the primary mechanism by which Acyclovir triphosphate inhibits viral replication?

It competes with deoxyguanosine triphosphate for viral DNA polymerase Signup and view all the answers

What type of drug is Sotrovimab, and how does it function in relation to Covid-19?

Monoclonal antibody that binds to spike proteins Signup and view all the answers

Which statement accurately describes the role of Remdesivir in treating viral infections?

It interferes with viral polymerase to inhibit replication Signup and view all the answers

Which of the following best describes Methotrexate's function as a cytotoxic agent?

Inhibits folate synthesis by blocking DHFR Signup and view all the answers

What is a common side effect associated with the use of Cisplatin as a cytotoxic agent?

Severe nausea and vomiting Signup and view all the answers

What characteristic distinguishes NNRTIs from other antiviral drugs?

Selectivity for reverse transcriptase Signup and view all the answers

What is the mechanism of action for Molnupiravir?

Implements mutations in the viral genome Signup and view all the answers

Which of the following accurately describes the impact of NRTIs on HIV treatment?

Blocks the activity of reverse transcriptase Signup and view all the answers

What type of toxicity is associated with Methotrexate?

Immunosuppression Signup and view all the answers

What is the primary purpose of protease inhibitors in HIV treatment?

Preventing the maturation of viral proteins Signup and view all the answers

What is a distinctive feature of Acyclovir compared to other antiviral medications?

It specifically targets viral polymerases Signup and view all the answers

Which statement is true regarding the side effects of Cisplatin?

It can lead to serious nephrotoxicity Signup and view all the answers

Which aspect of antiviral treatment does Molnupiravir primarily aim to exploit?

Viral genome mutation leading to resistance Signup and view all the answers

Study Notes

β-adrenoceptor agonists

Isoprenaline is a full agonist that binds to β1 and β2 receptors, causing increased heart rate and contraction.
Salbutamol, Terbutaline, Salmetarol, and Formoterol are partial agonists that primarily target β2 receptors.
Salbutamol and Terbutaline are short-acting β-adrenoceptor agonists (SABAs) used for acute asthma treatment.
Salmetarol and Formoterol are long-acting β-adrenoceptor agonists (LABAs) used for asthma prevention.
LABAs must be combined with inhaled corticosteroids.

Tyramine

Tyramine is structurally similar to norepinephrine (NA).
Tyramine is transported by the norepinephrine transporter (NET) into nerve terminals, limiting neuronal reuptake of NA.
Tyramine displaces NA from vesicles and increases NA in the junction, leading to activation of post-junctional adrenoceptors.
Tyramine can be metabolized by monoamine oxidase (MAO).

Biguanides

Metformin is a biguanide used for type II diabetes.
Metformin increases insulin-mediated glucose uptake.
Metformin reduces hepatic glucose production by activating AMP-activated protein kinase in the liver.
Metformin decreases carbohydrate absorption.
Metformin reduces LDL cholesterol and triglyceride levels.

Sulfonylureas

Sulfonylureas mimic the rapid peak in insulin that's absent in type II diabetes.
Sulfonylureas act on β cells to stimulate insulin secretion.
Sulfonylureas bind to K+ ATP channels, reducing K+ permeability and preventing K+ efflux.
This causes membrane depolarization, triggering the opening of Ca2+ channels for Ca2+ entry and insulin release.

Na+ - glucose cotransporter 2 (SGLT-2) inhibitors

SGLT-2 inhibitors increase the excretion of glucose.
They work by inhibiting the SGLT2 transporter, which decreases the resorption of blood glucose from the proximal convoluted tubule (PCT).
This leads to increased glucose excretion.

α-glucosidase inhibitors

α-glucosidase inhibitors inhibit intestinal α-glucosidase, which digests carbohydrates.
This delays carbohydrate absorption, allowing undigested carbs to reach the distal bowel for longer.
α-glucosidase inhibitors decrease the post-prandial rise in glucose.

Exogenous insulin

Exogenous insulin increases insulin to physiological levels.
It can interact with various drugs, including beta-blockers, corticosteroids, diuretics, and alcohol.

Dopamine reuptake inhibitors

Methylphenidate (Ritalin) and Atomoxetine (Strattera) are dopamine reuptake inhibitors used for ADHD.
They increase synaptic concentrations of dopamine by blocking reuptake.

Selective NA reuptake inhibitors

Reboxetine is a selective NA reuptake inhibitor used for depression.

Modafinil

Modafinil (Provigil) is a wakefulness-promoting agent used for learning and narcolepsy.
Its exact mechanism of action is unclear.

Glyceryl Trinitrate (GTN)

GTN is a prodrug that's converted to nitric oxide (NO).
NO stimulates guanylate cyclase in vascular smooth muscle, increasing cGMP.
This leads to vasodilation of collateral vessels, increasing oxygen supply and decreasing oxygen demand.

Glucagon-like peptide (GLP) 1 agonists

Liraglutide is a GLP-1 agonist used for obesity.
GLP-1 agonists mimic the effects of endogenous GLP-1, binding to GLP-1 receptors on the vagus nerve.

H2 receptor antagonist

Cimetidine and Famotidine are H2 receptor antagonists that competitively bind to the H2 receptor, blocking the binding of histamine on gastric parietal cells.
This reduces acid secretion.

Proton pump inhibitors

Omeprazole is a proton pump inhibitor that requires an acidic environment to activate.
It inhibits the proton pump, further reducing acid secretion.

Dopamine Agonist

Bromocriptine and Cabergoline are dopamine agonists
Both can be used as a monotherapy for Parkinson’s Disease
They act by stimulating the release of dopamine
Bromocriptine is not as targeted as Cabergoline which binds to all dopamine receptors
Bromocriptine is not as safe as Cabergoline as the latter is safe for asthmatics
Bromocriptine can cause hallucinations
Cabergoline improves bradykinesia and rigidity

L-DOPA

L-DOPA is an effective treatment for Parkinson’s Disease
L-DOPA is a precursor to dopamine
The conversion of L-DOPA to dopamine is stimulated by the dopamine decarboxylase enzyme
Both Bromocriptine and Cabergoline can be used as a monotherapy for Parkinson’s Disease
L-DOPA can make Parkinson’s symptoms worse overtime due to the degeneration of dopaminergic neurons
L-DOPA can cause dysrhythmias, orthostatic hypotension, pupil dilation, visual and auditory hallucinations, abnormal motor movement, mood changes, depression and anxiety

Ca+ Channel Antagonists

Dihydropyridines, Benzothiazepines and Phenylalkylamines are all Ca+ channel antagonists
All three act by preventing channels opening, thereby decreasing intracellular Ca2+ levels
They all decrease vascular contractile tone and BP
They may cause initial reflex tachycardia
Dihydropyridines are often used to treat angina pectoris
Benzothiazepines are often used to treat hypertension
Phenylalkylamines are often used to treat supraventricular tachycardias

Glyceryl Trinitrate

Glyceryl Trinitrate (GTN) is a prodrug that’s converted to NO
It stimulates guanylate cyclase in vascular smooth muscle
It increases cGMP which increases vasodilation of collateral vessels
It is typically administered sublingually to avoid first pass metabolism by the liver
It may cause reflex tachycardia and increased vascular tone
It may cause venous pooling and postural hypotension

Glucagon-like Peptide (GLP) 1 Agonist

Liraglutide is a GLP1 agonist
It’s used for obesity and type 2 diabetes
GLP1 is released naturally from the L cells in response to carbs, fats and proteins
GLP1 agonists mimic the effects of the endogenous GLP1 released by L cells
It binds to the GLP1 receptors on the vagus nerve
It can cause nausea, vomiting, diarrhoea and injection site reactions
It can cause pancreatitis although this is rare

H2 Receptor Antagonist

Cimetidine is an H2 receptor antagonist
It competitively binds to the H2 receptor which blocks the histamine binding to the parietal cells
It reduces gastric acid secretion
It’s used for peptic ulcer disease, GORD and dyspepsia.
It is a non-selective inhibitor of CYP450
It can interact with CYP450 enzymes and increase levels of other drugs

Proton Pump Inhibitors

Omeprazole is a proton pump inhibitor
It is a prodrug
It requires an acidic environment for activation
It’s used in combination with other drugs such as Acyclovir
It can cause constipation

Anti-HIV Drugs

NRTIs and NNRTIs are anti-HIV drugs
They are highly selective for HIV reverse transcriptase
Protease inhibitors also inhibit HIV replication
These drugs inhibit the reverse transcriptase enzyme to produce a double DNA strand

COVID-19 Drugs

Sotrovimab, Remdesivir and Molnupiravir are all used for COVID-19
Sotrovimab binds to spike proteins to prevent infection
Remdesivir is a viral polymerase inhibitor
Molnupiravir is also a viral polymerase inhibitor which implants mutations to inhibit viral growth

Cytotoxic Agents

Cisplatin and Methotrexate are cytotoxic agents
These are used for chemotherapy
Cisplatin binds covalently to cell components
It can cause severe nausea and vomiting, nephrotoxicity and neurotoxicity
Methotrexate inhibits folate synthesis by inhibiting DHFR
It's an immunosuppressant drug

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Description

This quiz explores the pharmacology of β-adrenoceptor agonists, focusing on their mechanisms, effects on heart rate, and their applications in treating respiratory conditions like asthma. Additionally, it covers the role of tyramine and biguanides such as metformin in influencing neurotransmitter dynamics and managing diabetes.