Multiple Choice Questions (MCQ) on Veterinary Pharmacology (Part-2)

ANSWERS & EXPLANATIONS

1.

a. (Omeprazole)

• Proton pump blockers prescribed at gastric ulcer: Omeprazole
• Stimulation of Cholinergic M1 and Histaminergic H2 receptors will increase gastric acid secretions.
• Dicyclomine is used to relieve gastrointestinal muscle spasm.
• Cimetidine, Ranitidine and Fomitidine (Selective H2 receptor antagonist) used to treat ulcer
• Ranitidine reduces volume of gastric juice, reduces nocturnal secretion of gastric acid and also increases Ph of the gastric juice. Ranitidine is preferred over Cimetidine as it does not inhibit hepatic microsomal enzymes, does not increase prolactin level as well as much less and convenient to patients.
• H2 receptor antagonists are indicated in Reflux oesophagitis, acute ulcerative colitis, duodenal ulcers etc.
• Histamine (H2 receptor) stimulation causes:
• Increase in cyclic AMP in cells
• Increase in gastric acid secretions
• Modulation of T lymphocyte activity and vascular dilation

Note:

Classification of anti – ulcer drugs:

• Proton Pump Inhibitor: Omeprazole, Lansoprazole and Rabeprazole
• H2 receptor Antagonist: Famotidine (Most potent one) , Ranitidine, Cimetidine, Lafutidine
• Mucosal protective drugs: Rebamipide, Teprenone, Polaprezinc, Sofalcone, Alginate sodium

 2.

d. (Ivermectin)
Ivermectin is contraindicated in Collie and its crossbreed dogs, result of the mutation of the MDR1 (Multi – Drug Resistance1) Gene.

Note:

The blood brain barrier of Collie and its cross bred dogs are deficient in P-gp protein.

3.

d. (2- PAM) or pralidoxime

Pralidoxime is an antidote of Organophosphate anticholinesterase pesticides, works by reactivating phosphorylated cholinesterase enzyme.

Methylene Blue (Active form- Leucomethylene), Antidote of Nitrite/nitrate Toxicity, converts methaemoglobin to haemoglobins.

Note:

• Ascorbic acid is effectively employed for the conversion of methomoglobins to hemoglobins in ruminants.
• Calcium Sodium EDTA (Antidote of lead toxicity)- Chelation
• D- penicillamine (Antidote of Copper Toxicity) – Chelation
• BAL (British Anti lewisite) (Antidote of Arsenic Toxicity) – Chelation
• Activated Charcoal (Antidote of DDT)- Adsorption
• Fluoroacetate (Antidote of Acetate poisoning) – Competitive Substitution

Note:

• Product formed by interaction of silver nitrate (Toxicants) and sodium Chloride (Antidotes) – Silver Chloride
• Product formed by interaction of Fluoride (Toxicants) and Calcium lactate (antidotes) – Calcium fluoride
• Product formed by interaction of Strychnine (Toxicants) and Tannic acid (antidotes) - Strychnine tannate
• Product formed by interaction of cyanides (Toxicants) and methaemoglobin (antidotes) – cyanomethaemoglobins

 4.  

b. (Penicillin – G)
Beta – lactams (Penicillin, glycopeptides, linezolid, Macrolides) has time dependent bactericidal activity, depends on the time that the concentration of the drug above the MIC, exposing to bacteria, correlating with efficacy of drug.

5.

d. (Flumazenil)

• Competitive antagonist of Benzodiazepine (Anxiolytics) receptors: Flumazenil
• Benzodiazepines receptors agonist: Diazepam, Lorazepam, clonazepam, Midazolam
• Full agonist on opioid receptor: Meperidine
• Competitive antagonist on opioid receptor: Naloxone
• Beta – receptors agonist: Albuterol, Metaproterenol, Pirbuterol, turbutaline, Levalbuterol
• Partial agonist on Beta- angiotensin receptor: Saralasin
• Non-Competitive antagonist on Alpha – adrenergic receptor: phenoxybenzamine
• selective adrenergic alpha-2 blocking agent: Yohimbine
• Selective postsynaptic alpha receptor blocking agents: Prazocine
• Block both adrenergic alpha and beta receptors: Labetolol
• Selective adrenergic Beta-2 receptor agonist - Salbutamol
• Selective adrenergic Beta-2 receptor antagonist - Butoxamine
• selective adrenergic beta-1 antagonist - Atenolol
• Example of serotonin receptor antagonist - Cyproheptadine
• Example of Histamine receptor antagonist- Metiamide
• Adrenergic beta blocker has a marked membrane stabilizing action - Propranolol
• The adrenergic beta receptor is said to be an enzyme - Adenyl cyclase

Note:

Agonist possesses both affinity and intrinsic activity while antagonist possesses only affinity not intrinsic activity

6.

b. (Amlodipine)
L- type Calcium - Channel blocker used to prevent supraventricular tachycardia : Amlodipine
Note:
Quinidine ( antiarrhythmic drug) used to treat irregular heart beat.
Captopril used to treat high blood pressure (Hypertension).
Amrinone (Type -3 phosphodiesterase inhibitor) used for short term treatment of heart failure.

7.

b. (Cats)

Glucouronide formation, drug detoxification mechanism, poor in Cats.

Drugs undergoes Glucouronide conjugations are Morphine, Acetaminophen, NSAIDS, Benzodiazepines.

8.

c. (Half- life)

• Sialic acid content in glycoprotein hormones determines it’s half life.
• Sialic acid are nine carbon atoms sugar usually present as terminal residues of glycoprotein and glycolipids, play important role in infection prevention.
• Example of Glycoprotein hormones: FSH (Follicle Stimulating hormones), TSH (Thyroid stimulating hormones)

9.

c. (Curcumin)

• Active principle in rhizomes of turmeric plants: Curcumin
• Active principle present in black pepper and long pepper: Piperine
• Active principle present in Neem: Azadirachtin
• Quercetin is a plant flavanol found in many fruits, vegetables, leaves, seeds and grains; capers, red onion and kale are common food containing it.

10.

b. (CYP3A4)

• More than 50% of drug undergo metabolism through CYP3A4.
• Cytochrome P450 3A4 is an important enzymes found in liver and in intestine, oxidizes small foreign organic molecules such as toxin and drugs, so they can be removed from the body. Highly homologous to CYP3A5.
• CYP1A1 is responsible for the metabolic activation of procarcinogens (Polycyclic aromatic hydrocarbons and aromatic amines) into reactive metabolites. Also participate in the metabolism of steroidal hormones (Oestrogens).
• CYP2D6 is a protein coding gene; Disease associated with CYP2D6 includes Drug metabolism poor, Cyp2d6 related and neuroleptic malignant syndromes.
• CYP2C9, involves in protein processing and transport, provides instructions for making an an enzymes that found in cell structure called endoplasmic reticulum.

11.

b. (Pharmacokinetics)

• The mathematical description of change in concentration of drugs or their metabolites in body is called Pharmacokinetics. What body does to drug – Pharmacokinetics
• Variation in drug response due to individual lifestyles – Pharmacogenetics
• Pharmacometrics: Science that quantifies drug, disease and trial information to aid efficient drug development and regulatory decisions.
• Pharmacodynamics: Study of a drug’s molecular, biochemical and physiologic effects on body.
• What drug does to body- Pharmacodynamics
• Chrono pharmacology: A branch of pharmacology studying the dependencies between the timing of drug administration and its effects.

12.

d. (Hepatotoxicant)

• Carbon tetrachloride is primarily hepatotoxicant.
• CCl3 is a non- flammable, colorless liquid with a heavy, sweet odor, used as cleaning fluid in home and industry.
• Also used as a grain fumigant.
• The hepatic injury induced by carbon tetrachloride is mediated by its metabolite: Trichloromethyl free radicals as well as trichloromethylperoxy free radicals.

13.

c. (Cypermethrin)

• Pyrethroids (Man made pesticides, produced from Chrysanthemum flower): Permethrin, Resmethrin, Sumithrin, Cypermethrin.
• The synergist that is added to pyrethroid compound in order to enhance its effect is piperonyl butoxide.
• Organophosphorus compound (Insecticides): Parathion (potent one), Malathion
• The toxic effect of malathion in mammals is due to Malaoxon.
• Organophosphorus compound that interact with both esteratic and anionic site of acetylcholine esterase is Echothiopate.
• Organochlorine compound (Insecticides) that does not accumulate in the body: Endosulfans
• Example of organochlorine: BHC (Benzene hexachloride)

Note:

Carbamates (Pesticides) acts by interacting esteratic as well as anionic sites of Acetylcholine Esterase.

14.

c. (German)

• The 1st pharmacopeia was compiled by a German.
• The 1st laboratory exclusively to the study of pharmacology was established by Ruaolpn buclcim.
• Creator of Modern Scientific Pharmacopeia – Charles Rice
• Father of Pharmacology – Rudolf Bucheim
• The term Anesthesia was coined by Oliver Holmes Wendell.

15.

c. (The surface area is large)
Most of the dose of aspirin (pka 3.5) are absorbed from the small intestine because of the large absorptive surface area.

Factors affecting Absorption:

Related to drugs

• Lipid water solubility (↑ coefficient ↑ absorption)
• Molecular size (smaller size rapid absorption)
• Particle size (smaller particle size rapid absorption)
• Degree of Ionization (Unionized forms absorbs rapidly)
• Physical forms (Gaseous>liquid>solid) -
• Chemical natures
• Dosage forms
• Formulation (Include Sodium which can interact to decrease absorption)
• Concentration (Higher the concentration, more flux across the membrane)

Related to body

• Area of absorptive surface
• Vascularity
• PH
• Presence of other substance
• GI motility
• Functional integrity of absorptive surfaces
• Disease

16.

d. (All)

Factor affecting distribution of drug

Related to Drug

• Lipid solubility (↑lipid solubility ↑ distribution)
• Molecular size (↑ size less distribution)
• Degree of ionizations
• Cellular binding
• Duration of actions
• Therapeutics effects (Bisphosphonates bind with bone matrix cells and strengthen them, used in the treatment of osteoporosis).
• Toxic effects (Chloroquinine deposited in retina, tetracycline binds with bone material)

Related to body:

• Vascularity (blood passes highly profuse organ (75%) while remaining (25%) pass to less profuse area.
• Transport mechanism ( different compartment – different mechanism) lipid soluble drug – passive transport while active transport occurs where carrier protein are present.
• Blood barrier
• Plasma binding protein
• Free and bound form of drug
• Drug interaction
• Disease
• Volume of distribution (V= Dose of the drug/ plasma concentration of drug).

17.

b. (Must be diluted beyond the bacteriostatic level for sterility test)
Solutions that contain bacteriostatic agents must be diluted beyond the bacteriostatic level for sterility test.

18.

b. (2-5 kcal/mole)

• The bond strength of the hydrogen bond is 2-5kcal/mole.
• The hydrogen bond are classified based on strength of interaction, 3 classes are distinguished: weak, Moderate and strong.
• The weak hydrogen bond involve less polar group in proton donor like C-H or less polar acceptor like N2 molecules. Strength ranges about 0.5kcal -5 kcal /mole.
• Moderate hydrogen bond strength ranges from 5-15kcal/mole
• Strong hydrogen bond strength ranges from 15-40kcal/mole.

19.

d. (None)
Difference between bound and Unbound Form of Drug

Bound form of Drug	Unbound form of Drug
Non – diffusible form	Diffusible form
Can not cross endothelial barrier	Cross endothelial barrier
Can not combine with receptors	Combine with receptors
Inactive	Active
Not available for metabolism and excretion	Available for metabolism and excretion
Long duration of action (long half –life)	Short duration of action ( short half life)

20.

a. (1500 BC)
Ebers's papyrus is an old compilation of disease conditions and prescriptions for medicaments. It was written about 1500 BC.
Ebers's papyrus is a preserved medical document from ancients Egypt, longer and more complete than the Edwin Smith Papyrus, and about as old, it is a collection of diverse medicals texts that offers the most complete record of Egyptian medicine.

21.

d. (All)

Factors affecting dose and actions of the drugs:

• Age: Young ones requires less doses than adults. Either Young’s formula (based on age) or Clark’s formula (based on weight) used for calculating dose, but formula based on body surface area is more reliable.
• Sex: Female adults requires smaller dose than male due to presence of more body fat.
• Body weight:
• Severity of disease: More severe require more doses (dull headache relieved by single tablet whereas severe headache requires 2-3 tablets of same drug) but not true in all cases, in case of iron deficiency anaemia, dose of iron salt administered orally remain same irrespective of severity.
• Health and nutrition: Debilitated and anaemic patients more sensitive to toxic effect of drug and requires smaller dose.
• Pathological state:
• Tolerance
• Simultaneous administration of 2 or more drugs: Addition, synergism antagonism
• Route of administration
• Time and frequency of drug administration
• Idiosyncrasy
• Allergy

22.

a. (Mutagenesis)

• Abnormalities of the genetic material (gene chromosomes) caused by the drug is called: Mutagenesis
• Oncogenesis/ Tumorigenesis/ Carcinogenesis: Formation of the cancer whereby normal cells are transformed into cancer cells.
• Teratogenesis occurs when a drug taken during early stages of pregnancy causes developmental abnormalities in the fetus.

23.

c. (Both of above)
Double –reciprocal plot has been applied widely to the analysis of Both competitive antagonism and non-competitive antagonism.
The double –reciprocal (Also known as the Lineweaver- Burk) plot is created by plotting the inverse initial velocity (1/V0) as a function of the inverse of the substrate concentration (1/(S)).
This Lineweaver Burk plot is convenient because it allows a way to determine the exact value for the Michaelis constant and the maximal velocity.

24.

c. (Observations of the animals from birth to maturity including the above two)
After thalidomide disaster, following animal tests are felt mandatory for new drugs:
-Administration of drugs to both sexes before mating
-Administration of drug throughout pregnancy
- Observations of animals from birth to maturity.

Note:

Thalidomide is the drug used for the treatment of nausea in pregnant women, resulted in the severe birth defects in thousands of children.

25.

d. (All)

• Sublingual administration refers to the placement of drugs under the tongue. The sublingual route bypasses the 1st –pass metabolism and hence facilitates rapid absorption of the drug into the systemic circulation using blood vessels.
• Sublingual administration can be adopted for the following drugs: Glyceryl trinitrate, Methyl testosterone, Oxytocin etc.
• Sublingual drug administration's give quick onset of actions.

26.

a. (Convenient mode of administration in presence of vomiting)
Rectal Administration of drugs is convenient mode of drug administration in presence of vomiting or nausea.
These rectal formulations are based on conventional dosage forms, such as suppositories and enemas.

27.

c. (Both a and b)

Facts related oral drug administration:

• Convenient
• Cost –effective
• Most commonly used medications
• Primary site of absorption – Small intestine
• Bioavailability of the medication is influenced by the amount of drug absorbed across the intestinal epithelium.

28.

b. (Is for systemic or local effects)

• Drug administration by inhalation is for systemic or local effects.
• Drug administration by inhalation through the mouth must be atomized into smaller droplets than those administered by the nasal route, so that the drugs can pass through the windpipe and into the lung. How deeply into the lung they go depends on the size of the droplets.
• An inhaled medication route can be utilized to administer albuterol or corticosteroids such as fluticasone, and to deliver inhaled anesthetics to patients.

29.

d. (AUC (Area Under Curve) (Oral) and AUC (I.V) (%))

30.

a. (Acidic drug are bound to the albumin fractions)
- Acidic drugs are bound to the albumin fraction, leads to increases plasma half- life.

Since it's a part-2 for part -1, visit: https://veterinarylectures.com/multiple-choice-questions-on-pharmacology-part-1/

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