The Important Questions of Pharmacology for NEET PG exam:
- Which of the following is true regarding Maraviroc?
A. Not active orally
B. Bind to transmembrane glycoprotein
C. Targets the CXCR4 receptor
D. Impairs immune surveillance
Correct answer : D. Impairs immune surveillance
HIV virus attachment process. 1 – gp120 attaches to CD4+ receptor. 2 – gp120 variable loop attaches to co-receptor (CCR5 or CXCR4), gp41 fixation to the cell membrane. 3 – HIV virion enters the cell.
Maraviroc is a CCR5 receptor inhibitor.
It interferes with the attachment of HIV virus to the host cell.
It has no effect on the strains of HIV which are tropic for CXCR4 receptor.
It is given orally.
Impaired immune surveillance can result due to blocking of human chemokine receptor CCR5.
- Most potent fluoroquinolone against Mycobacterium leprae is?
A. Levofloxacin
B. Ofloxacin
C. Moxifloxacin
D. Ciprofloxacin
Correct answer : C. Moxifloxacin
Photomicrograph of Mycobacterium leprae – small brick red rods found in clusters
Ciprofloxacin has poor activity against Mycobacterium leprae.
Ofloxacin, Pefloxacin, Moxifloxacin and Sparfloxacin have high level of activity against Mycobacterium leprae.
Among them, Moxifloxacin is the most potent.
- The antiretroviral drug combination to be avoided is?
A. Zidovudine + Stavudine
B. Zidovudine + Lamivudine
C. Didanosine + Abacavir
D. Didanosine + Zidovudine
Correct answer : A. Zidovudine + Stavudine
The combination of Zidovudine with Stavudine has pharmacodynamic antagonism and hence should be avoided.
Other antiretroviral drug combinations to be avoided are:
Stavudine + Didanosine – Increased toxicity (neuropathy and lactic acidosis)
Lamivudine + Didanosine – No additive action seen
- Basiliximab is?
A. anti CD3 antibody
B. anti CD25 antibody
C. IL1 receptor antagonist
D. TNF alpha inhibitor
Correct answer : B. anti CD25 antibody
Basiliximab is an anti CD25 antibody.
It has high affinity for interleukin 2 receptor.
Plasma half life is shorter (1 week) compared to Daclizumab (3 weeks).
It is used for the prevention of rejection reactions in transplant patients.
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- Shortest acting non benzodiazepine hypnotic is?
A. Zaleplon
B. Zolpidem
C. Zopiclone
D. Eszopiclone
Correct answer : A. Zaleplon
Zaleplon is the shortest acting non benzodiazepine hypnotic.
It has selective action on benzodiazepine receptors containing alpha 1 subunit.
It has rapid hepatic clearance with a half life of one hour.
Morning sedation is absent due to shortness of action.
- Amylin analogue is?
A. Sitagliptin
B. Liraglutide
C. Nateglinide
D. Pramlintide
Correct answer : D. Pramlintide
Amylin (Islet Amyloid Polypeptide) is produced by pancreatic beta cells.
Pramlintide is an amylin analogue.
It is given as subcutaneous injection before meals.
It reduces postprandial glucose levels.
It also has a centrally mediated anorectic action.
- Pegvisomant is approved for the treatment of?
A. Parkinsonism
B. Hyperprolactinemia
C. Amenorrhoea
D. Acromegaly
Correct answer : D. Acromegaly
Pegvisomant is a polyethylene glycol complexed mutant growth hormone.
It is used for the treatment of acromegaly caused by small pituitary adenoma.
It binds to growth hormone receptor and prevents triggering of signal transduction.
It is a GH antagonist.
- All are true regarding leflunomide except?
A. Inhibits proliferation of stimulated lymphocytes
B. Depresses antibody production by B lymphocytes
C. Can be used in children
D. Can cause thrombocytopenia
Correct answer : C. Can be used in children
Conversion of leflunomide into its active metabolite
Leflunomide is an immunomodulator.
It is used in patients with active rheumatoid arthritis.
It inhibits proliferation of stimulated lymphocytes.
The active metabolite of leflunomide inhibits dihydroorotate dehydrogenase and pyrimidine synthesis.
It can depress the antibody production by B cells.
It should not be used in children and pregnant / lactating women.
- Which of the following does not have significant first pass metabolism?
A. Labetalol
B. Acebutolol
C. Atenolol
D. Metoprolol
Correct answer : C. Atenolol
Structure of atenolol
Atenolol is a selective beta 1 blocker.
The lipid solubility is low.
Oral absorption is incomplete.
First pass metabolism is not significant.
All other drugs mentioned have significant first pass metabolism.
- Which of the following is true regarding Drotaverine?
A. M3 selective muscarinic antagonist
B. Causes smooth muscle contraction
C. Causes anticholinergic side effects
D. Inhibits phosphodiesterase-4
Correct answer : D. Inhibits phosphodiesterase-4
Drotaverine
Drotaverine is a smooth muscle antispasmodic.
Mechanism of action is inhibition of phosphodiesterase-4 selective for smooth muscle.
It causes smooth muscle relaxation.
It does not have anticholinergic side effects.
- Which is associated with vaginal carcinoma in female offspring?
A. Diethylstilbestrol
B. Phenytoin
C. ACE inhibitors
D. Indomethacin
Correct answer : A. Diethylstilbestrol
Chemical structure of Diethylstilbestrol
Diethylstilbestrol can cause vaginal clear cell adenocarcinoma in girls and young women exposed to it in utero.
Phenytoin can cause fetal hydantoin syndrome which is characterised by hypoplasia of the phalanges, cleft lip, cleft palate and microcephaly.
Indomethacin / aspirin can cause premature closure of the ductus arteriosus.
Clear cell adenocarcinoma of ovary. Shown to illustrate characteristic clear cytoplasm rich in glycogen.
- Which of the following can cause discolouration of teeth in the fetus?
A. Lithium
B. Tetracycline
C. Warfarin
D. Isotretinoin
Correct answer : B. Tetracycline
Structure of tetracycline
Intake of tetracycline by pregnant women results in the discolouration and deformity of teeth in the fetus. It can also produce impairment of bone growth.
Lithium can cause fetal goitre and cardiac abnormalities.
Warfarin can cause fetal warfarin syndrome (Warfarin embryopathy) which is characterised by growth retardation, depressed nose and defects of the eye and hands.
Isotretinoin can produce craniofacial, heart and CNS defects. It can also induce hydrocephalus.
- Intake of which of the following is associated with neural tube defects?
A. Phenytoin
B. Lithium
C. Valproate
D. Phenobarbitone
Correct answer : C. Valproate
Valproate is a teratogenic drug which causes spina bifida and other neural tube defects in the fetus when taken by pregnant women. It can also cause heart and limb abnormalities.
Lithium can cause fetal goitre and cardiac abnormalities.
Phenytoin can cause fetal hydantoin syndrome which is characterised by hypoplasia of the phalanges, cleft lip, cleft palate and microcephaly.
Spina bifida occulta – Xray pelvis
- Phocomelia is an adverse effect of?
A. Diethylstilbestrol
B. Thalidomide
C. Valproate
D. Progestins
Correct answer : Thalidomide
Intake of thalidomide by pregnant women is associated with the presence of phocomelia and multiple defects of internal organs of neonates. It is a teratogenic drug and is classified under category X in the risk classification of drugs used in pregnancy.
Diethylstilbestrol can cause vaginal clear cell adenocarcinoma in girls and young women exposed to it in utero.
Valproate can cause spina bifida and other neural tube defects in the fetus when taken by pregnant women. It can also cause heart and limb abnormalities.
Progestins can cause virilization of female fetuses.
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- Volume of distribution of Paracetamol is?
A. 500 ml/kg body weight
B. 1 L/kg body weight
C. 5 L/kg body weight
D. 25 L/kg body weight
Correct answer : B. 1 L/kg body weight
VOLUME OF DISTRIBUTION
After a drug enters the blood, it is distributed to various other tissues.
The pattern of drug distribution is influenced by:
Lipid solubility (lipid insoluble drugs are limited to the extracellular compartment)
Degree of plasma protein / tissue protein binding
Existence of tissue specific transporters
Ionisation of the drug at physiological pH (depends on pKa)
Variation in the blood flow to different tissues.
Apparent volume of distribution
Assuming that the body is a homogeneous compartment with a volume of V, the apparent volume of distribution can be calculated as follows:
V = Amount of drug administered IV / Plasma concentration of the drug
But the body is not a homogenous compartment.
Some drugs may be concentrated in certain body tissues.
In that case, even after administering a large quantity of the drug, the plasma concentration will be low.
Here, the apparent volume of distribution is large.
Other drugs may be limited to the intravascular compartment.
Here, the volume of distribution is equal to the blood volume.
Volume of distribution of some important drugs:
Drugs with high plasma protein binding like warfarin and diclofenac are mostly limited to the intravascular compartment. Here the volume of distribution is very low. ( approximately 0.15 L/kg)
Lipid insoluble drugs like streptomycin and gentamicin do not enter the intracellular compartment. Hence their volume of distribution is equal to the extracellular fluid volume. ( approximately 0.25 L/kg)
Drugs which are sequestered in body tissues have a high volume of distribution. e.g. Morphine (3.5 L/kg), Propranolol (4 L/kg), Digoxin (6 L/kg).
Clinical significance:
Drugs with high volume of distribution are difficult to remove via hemodialysis in cases of poisoning.
Volume of distribution may be altered in disease conditions by various mechanisms like change in membrane permeability, variation in the distribution of body water and alteration in the drug binding proteins.
- Who is known as the Father of Pharmacology?
A. Oswald Schmiedeberg
B. J Langley
C. Rudolf Buchheim
D. Paul Ehrlich
Correct answer : A. Oswald Schmiedeberg
Father of Pharmacology – Oswald Schmiedeberg
Oswald Schmiedeberg was a German pharmacologist.
He is regarded as the Father of Pharmacology.
He put forward many fundamental concepts in pharmacology.
- Which of the following is not an action of muscarinic antagonists?
A. Reduce respiratory secretions
B. Reduce gastric secretions
C. Contraction of radial muscles of iris
D. Increase rate of conduction in the heart
Correct answer : C. Contraction of radial muscles of iris
Contraction of radial muscles of iris is brought about by the sympathetic nervous system (produces mydriasis).
They have no parasympathetic innervation.
Muscarinic antagonists produce mydriasis by inducing relaxation of circular muscles of iris.
ACTIONS OF MUSCARINIC ANTAGONISTS
Reduction of secretions in the gastrointestinal tract and respiratory system (used as pre anaesthetic medication).
Increases the heart rate and rate of conduction.
Some anticholinergics (like hyoscine) have antiemetic action and are used for treatment of motion sickness.
Smooth muscle relaxation
Bronchodilation – used for treatment of asthma.
Relaxation of circular muscle of iris (mydriasis) – used in ophthalmological diagnosis.
Antispasmodic action for treatment of GI hypermotility and overactive bladder.
- Buprenorphine is a?
A. Partial mu agonist
B. Full mu agonist
C. Partial kappa agonist
D. Full kappa agonist
Correct answer : A. Partial mu agonist
BUPRENORPHINE – PHARMACOLOGY
Buprenorphine is a semi-synthetic, mixed opioid agonist–antagonist
It is a partial mu agonist and a kappa antagonist
It is used as an analgesic and also for treatment of opioid addiction
- Which of the following is an integrase inhibitor currently in use for the treatment of HIV infection?
A. Indinavir
B. Elvitegravir
C. Saquinavir
D. Raltegravir
Correct answer : D. Raltegravir
Integrase inhibitors inhibit the enzyme ‘integrase‘ which inserts the viral genome into the host DNA.
Raltegravir was the first integrase inhibitor approved by the US FDA (in 2007).
Elvitegravir and Dolutegravir are 2 other integrase inhibitors approved in 2012 and 2013 respectively
Raltegravir is the correct answer because at the time of the exam (AIPG 2011), it was the only integrase inhibitor available commercially
- Tolerance develops to all of the following effects of opioids except?
A. Euphoria
B. Miosis
C. Analgesia
D. Nausea
Correct answer : B. Miosis
Opioid tolerance does not develop for Constipation, Convulsions and Miosis.
- Which of the following is used to decrease the toxicity of amphotericin B?
A. Dose reduction
B. Liposomal delivery systems
C. Supplementing glucose
D. Giving it along with flucytosine
Correct answer : B. Liposomal delivery systems
Liposomal delivery systems decrease the amount of free drug in the blood. Infected cells interact with the liposomes, resulting in the release of amphotericin B at the site of action.
- False statement regarding phenytoin is?
A. It is a teratogenic drug
B. Highly protein bound
C. Induces insulin secretion
D. Follows saturation kinetics
Correct answer : C. Induces insulin secretion
Phenytoin inhibits insulin secretion and causes hyperglycemia.
- MAO inhibitors are contraindicated in a patient taking?
A. Pethidine
B. Buprenorphine
C. Morphine
D. Pentazocine
Correct answer : A. Pethidine > D. Pentazocine
Use of MAO inhibitors in patient taking pethidine / pentazocine can precipitate serotonin syndrome.
- Ethosuximide is the drug of choice for treatment of ?
A. Generalized tonic clonic seizures
B. Absence seizures
C. Simple partial seizures
D. Complex partial seizures
Correct answer : B. Absence seizures
Ethosuximide is the drug of choice for treatment of absence seizures. Other drugs used in the management of absence seizures are valproic acid, lamotrigine and clonazepam.
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- All of the following drugs cross the placenta except?
A. Phenytoin
B. Diazepam
C. Morphine
D. Heparin
Correct answer : D. Heparin
Heparin does not the cross the placenta. Hence its safe for use in pregnant patients who need anticoagulation.
- Which of the following drugs have a narrow therapeutic index?
A. Lithium
B. Diazepam
C. Penicillin
D. Desipramine
Correct answer : A. Lithium
Other drugs with narrow therapeutic index:
Digoxin
Gentamicin
Amphotericin B
Levothyroxine
Prazosin
Theophylline
Quinidine
Warfarin
Valproic acid
- Which of the following is used for the treatment of chlamydia infection in pregnancy?
A. Tetracycline
B. Erythromycin
C. Azithromycin
D. Doxycycline
Correct answer : C. Azithromycin
Preferred agent for treatment of chlamydia infection in pregnancy in azithromycin. It is given as a single dose of 1g leading to high compliance rate.
- Ibrutinib is used for the management of ?
A. Chronic Myelogenous Leukemia
B. Acute Lymphoblastic Leukemia
C. Mantle Cell Lymphoma
D. Lymphocyte rich Hodgkin’s Lymphoma
Correct answer : C. Mantle Cell Lymphoma
Ibrutinib is an orally administered selective inhibitor of Bruton’s tyrosine kinase (BTK)
It was approved by the US FDA on November 13, 2013 for the treatment of patients with mantle cell lymphoma who have received at least one prior therapy
Dose: 560 mg once daily, taken orally
- Simeprevir is used for the treatment of ?
A. HIV
B. CMV infection
C. Kaposi sarcoma
D. Chronic Hepatitis C
Correct answer : D. Chronic Hepatitis C
Simprevir is a drug recently approved by the US FDA for the treatment of chronic Hepatitis C infection
It is an orally active, hepatitis C virus, NS3/4A protease inhibitor
It is given in a one daily dosage
- Tyrosine kinase inhibitors are useful in the management of ?
A. Acute myeloid leukemia
B. Small cell carcinoma of lung
C. Gastrointestinal stromal tumors
D. Neurofibromatosis
Correct answer : C. Gastrointestinal stromal tumors
Tyrosine kinase inhibitors are used in the treatment of:
Chronic myeloid leukemia
Acute lymphoblastic leukemia ( philadelphia chromosome positive cases )
Head and neck malignancies
Non small cell carcinoma lung
Gastrointestinal stromal tumours
Hepatocellular cancer
Renal cell carcinoma
Pancreatic cancer
Colorectal cancer