Which of the following administration routes for drugs is more significantly affected by first-pass metabolism?
Oral
Sublingual
Intravenous
Rectal
Intramuscular
A concentration-response study on a muscarinic agonist was conducted. An unknown compound was added, and the study was repeated. It was noticed that the curve has shifted downwards in the presence of the unknown compound (Emax has decreased but EC50 has not changed). Which one of the following is CORRECT?
The compound is an inhibitor of adenylate cyclase enzyme
The compound is a competitive antagonist of muscarinic receptor
The compound is a non-competitive antagonist of muscarinic receptors
The compound is an agonist of muscarinic receptor
The compound is a non-competitive antagonist of nicotinic receptor
Which of the following neurotransmitters is released from preganglionic fibres of the sympathetic division?
noradrenaline
adrenaline
acetylcholine
dopamine
both a and c
The addition of glutathione to a drug molecule:
Decreases drug’s water solubility
Leads to inactivation of the drug
Is an example of a Phase I reaction
Occurs at the same rate in adults and new-borns
Involves cytochrome P450
Which of the following are likely to be excreted more rapidly in basic urine
Weakly basic drugs
Lipid soluble drugs
Weakly acidic drugs
Protein conjugated substances
None of the above
Drug absorption via active transport (select the incorrect answer)
Is an energy consuming process
Cannot be saturated
Can transport drugs against the concentration gradient
Occurs through specific proteins
Present in many tissues such as the kidney and the brain
Which of the following is not a phase I drug metabolising process?
reduction
acetylation
hydrolysis
oxidation
demethylation
There are two types of Acetylcholine (AChRs) receptors, muscarinic and nicotinic. The nicotinic AChRs are
Water soluble membrane pores
Are protein bound slow ion channels
Are G-coupled metabolic receptors
Ligand-gated, fast transmission ion channels
None of the above
Increased binding of drugs to plasma proteins
Reduces drug interaction
Increases the volume of drug distribution
Render the drug more long lasting
Facilitate renal filtration
All of the above
Which one of the following is NOT a beta-blocker
Doxazosin
Propranolol
Carvedilol
Timolol
Atenolol
Activation of M2 subtype of the muscarinic receptor mediates what functional effect in the heart?
Decrease the force and rate of contraction
Increase excitation-contraction coupling in the heart
Increase rate of cellular contraction
Increase force of contraction
None of the above
Second generation antihistamines differ from first generation largely
Due to their shorter half-life
Due to their greater potency
By having less CNS related side effects
Due to their greater affinity for target receptor
By having more gastric related side effects
Salbutamol is used for treatment of asthma, bronchoconstriction and COPD, what is its mechanism of action?
Alpha-1 agonist
Beta-1 antagonist
Beta-2 agonist
Alpha & Beta antagonist
Muscarinic antagonist
Which of the following is not a G-coupled receptor?
Rhodopsin
Adrenergic receptor
Prostaglandin EP1 receptor
Serotonin receptor
GABAA receptors
All of the following reduce or neutralize acidity in the stomach, EXCEPT
Magnesium hydroxide
Cimetidine
Omeprazole
Loratadine
Ranitidine
P-glycoprotein is a transmembrane protein. Its function involves:
Facilitating the influx of sodium ions into the cell
Allowing large drug molecules to cross the cell membrane
Pumping drugs outside the cell
The activation of G-protein coupled receptors
The inhibition of protein-kinase receptor
Atropine is a parasympatholytic. It acts by:
Blocking the ganglionic nicotinic receptors
Activating the cholinesterases
Preventing the release of acetylcholine from nerve endings
Preventing acetylcholine from interacting with muscarinic receptors
Inhibiting the synthesis of acetylcholine
Drug dissociation constant Kd is used to describe which of the following:
Potency.
Efficacy.
Affinity.
Stability.
Bioavailability.
Which one of the following statements concerning the parasympathetic nervous system is correct?
The parasympathetic system uses norepinephrine as a neurotransmitter.
The parasympathetic system often discharges as a single, functional system.
The parasympathetic division is involved in accommodation of near vision, movement of food, and urination.
The postganglionic fibres of the parasympathetic division are long compared to those of the sympathetic nervous system.
The parasympathetic system controls the secretion of the adrenal medulla.
Remedies for nasal stuffiness often contain which one of the following drugs?
Beta antagonist.
Muscarinic antagonist
Alpha blocker
Beta agonist
Alpha agonist
When a drug reduces the basal activity of a receptor, it is said to be:
A full agonist
An inverse agonist
An antagonist
A Partial agonist
A reverse agonist
The drug levodopa can slow down the progression of Parkinson’s disease because it:
Blocks NMDA receptors for glutamate
Blocks GABAA receptors
Is a precursor of dopamine
Activates serotonergic receptors
Stimulates dopaminergic receptors
Which combination of enzymes are involved with the synthesis of prostaglandins?
1- Cyclooxygenase
2-Lipoxygenase
3- Phospholipase-A2
4- Prostaglandin isomerase
5- Thromboxane synthase
1 + 2
2 + 3
3 + 4
1 + 3
3 + 5
A 60-year-old female who had a cancerous growth in the neck region underwent radiation therapy. Her salivary secretion was reduced due to radiation and she suffers from dry mouth (xerostomia). Which drug would be most useful in treating xerostomia in this patient?
Atropine
Pilocarpine
Muscarin
Acetylcholine
Noradrenaline
Sarin is a nerve gas that is an organophosphate cholinesterase inhibitor. Which agent could be used as an antidote to sarin poisoning?
Pilocarpine
Carbachol
Atropine
Physostigmine
Bethanechol
Which of the following classes of agents can be used in treatment of hypertension?
α1 Agonist
α2 Agonist
β1 Agonist
β3 Agonist
β2 Antagonist
A 12-year-old boy with a peanut allergy is brought to the emergency room after accidental consumption of peanuts. He is in anaphylactic shock. Which of the following drugs is most appropriate to treat this patient?
Norepinephrine
Phenylephrine
Dobutamine
Epinephrine
Atropine
Which one of the following statements is correct regarding benzodiazepines?
Benzodiazepines directly open chloride channels.
Benzodiazepines show analgesic actions.
Clinical improvement of anxiety requires 2 to 4 weeks of treatment with benzodiazepines.
Benzodiazepines cannot cross the blood-brain barrier
All benzodiazepines have some sedative effects.
Which medication should be prescribed to all angina patients to treat an attack?
Isosorbide dinitrate
Nitroglycerin patch
Nitroglycerin sublingual tablet or spray
Diazepam tablet
Captopril tablet
A 43-year-old heavy machine operator complains of seasonal allergies. Which medication is most appropriate for management of his allergy symptoms?
Diphenhydramine
Doxylamine
Hydroxyzine
Fexofenadine
Chlorpheniramine
