- Cross resistance of isoniazid is seen with
a) Rifampicin
b) Ethionamide
c) Cycloserine
d) Ethambutol
Answer: Ethionamide
Explanation:
The presence of a mutation in the inhA regulatory region together with a mutation in the inhA coding region can lead to the development of high-level isoniazid resistance and cross-resistance to ethionamide among the MDR-TB strains.
Isoniazid is one of the most effective drugs for the treatment of tuberculosis (TB).
Ethionamide is a second-line drug used in the treatment of multidrug-resistant (MDR) TB.
Both compounds are pro-drugs that need activation by different enzymes but share common pathways, which can lead to cross-resistance.
- Which drug is not acetylated?
a) INH
b) Dapsone
c) Hydralazine
d) Metoclopramide
Answer: Metoclopramide
Explanation:
Phase II metabolic reactions:
Glucuronidation
Acetylation
Methylation
Sulfation
Glycine conjugation
Drugs metabolized by acetylation:
INH
Hydralazine
Sulphonamide (Dapsone)
PAS
- Which is a pro-drug?
a) Enalapril
b) Clonidine
c) Salmeterol
d) Acetazolamide
Answer: Enalapril
Explanation:
Pro-drugs:
S-methyldopa
Levodopa
Enalpril
Sulfasalazine
Fluoro-uracil
Mercaptopurine
- Free water clearance decreased by
a) Vincristine
b) Vinblastine
c) Chlorpropamide
d) Frusemide
Answer: Frusemide
Explanation:
Free water clearance (CH2O) is the volume of blood plasma that is cleared of solute-free water per unit time.
Loop of Henle generates a cortico-medullary gradient by a counter current mechanism.
Loop diuretics abolish the cortico-medullary gradient; and block positive as well as negative free water clearance.
- Which of the following antibiotics acts by inhibiting cell wall synthesis?
a) Cefipime
b) Aminoglycosides
c) Erythromycin
d) Doxycycline
Answer: Cefipime
Explanation:
Cell wall synthesis inhibitors:
Beta lactam antibiotics:
Penicillins
Cephalosporins
Carbapenems
Mono-bactums
Other antibiotics:
Vancomycin
Bacitracin
- Which drug would treat both dermato-physis and candidal infection?
a) Ketoconazole
b) Griseofulvin
c) Nystatin
d) Tolnafet
Answer: Ketoconazole
Explanation:
Ketoconazole is the first orally effective broad spectrum anti-fungal drug useful in both dermato-physis and candidal infection.
- All of the following drugs are useful in detrusor instability except
a) Solefenacin
b) Tolterodine
c) Flavoxate
d) Duloxetine
Answer: Duloxetine
Explanation:
Drugs used in detrusor instability:
Darifenacin
Flavoxate
Oxybutynin
Solefenacin
Tolterodine
Indications of Duloxetine: Three birds with one stone
Stress urinary incontinence
Major depressive disorder
Diabetic poly-neuropathic pain
- Which of the following factors do not result in increased risk of digitalis toxicity?
a) hypo-magnesemia
b) Hyper-calcemia
c) Hyperkalemia
d) Renal failure
Answer: Hyperkalemia
Explanation:
Factors precipitating digitalis toxicity:
Hypo-kalemia
Hypoxemia
Hyper-calcemia
Hypo-magnesemia
Renal insufficiency
MI, Hypothyroidism and Hyperthyroidism
Drugs raising the serum concentration of Digoxin:
Quinidine
Verapamil
Amiodarone
Propafenone
- Which of the following drugs used in osteoporosis acts both be decreasing the resorption of bone as well as inducing new bone formation?
a) Teriparatide
b) Ibadronate
c) Strontium ranelate
d) Calcitonin
Answer: Strontium ranelate
Explanation:
Strontium ranelate is a novel anti-osteoporotic agent approved for the treatment of postmenopausal osteoporosis.
In contrast to other available treatments for osteoporosis, Strontium ranelate induces anti-resorption and bone-forming effects.
Strontium ranelate reduces bone resorption by decreasing osteoclast differentiation and activity, and stimulates bone formation by increasing replication of pre-osteoblast cells, leading to increased matrix synthesis.
- All of the following drugs require dose reduction in cirrhosis except
a) Lorazepam
b) Diazepam
c) Metronidazole
d) Rifampicin
Answer: Lorazepam
Explanation:
Benzodiazepine not metabolized in Liver:
Lorazepam
Oxezapam
Temazepam
- All of the following drugs can cause neuroleptic malignant syndrome except
a) Amantadine
b) Domperidone
c) Haloperidol
d) Metoclopramide
Answer: Amantadine
Explanation:
Neuroleptic malignant syndrome (NMS) refers to the combination of hyperthermia, rigidity, and autonomic dys-regulation that can occur as a serious complication of the use of antipsychotic drugs.
Central D2 receptor blockade in the hypothalamus, nigro-striatal pathways, and spinal cord leads to increased muscle rigidity and tremor via extra-pyramidal pathways.
Hypothalamic D2 receptor blockade results in an elevated temperature set point and impairment of heat-dissipating mechanisms.
Drugs That Can Cause Neuroleptic Malignant Syndrome:
Anti-emetics:
Domperidone
Metoclopramide
Prochlorperazine
Promethazine
Antipsychotics:
Haloperidol
Clozapine
Olanzapine
Fluphenazine
Risperidone
- A 56 years old female presented with breast carcinoma and she was prescribed herceptin (trastuzumab) which of the following statement regarding this drug is true
a) It is an antibody produced entirely from mouse containing on human component
b) It is a monoclonal antibody produced by injecting her-2 antigen
c) Injection of herceptin increases antibody response
d) The protein HER 2/Neu is expressed in increased amount by breast cancer cells
Answer: It is a monoclonal antibody produced by injecting her-2 antigen
Explanation:
A recombinant humanized monoclonal antibody directed against the human epidermal growth factor receptor 2 (HER2).
After binding to HER2 on the tumor cell surface, trastuzumab induces an antibody-dependent cell-mediated cytotoxicity against tumor cells that over-express HER2.
HER2 is over-expressed by many adeno-carcinomas, particularly breast adeno-carcinomas.
- Which of the following statements regarding ACE inhibitors is true?
a) These convert Angiotensinogen to angiotensin 1
b) Omission of prior diuretic dose decreases the risk of postural hypotension
c) Lisinopril is shorter acting the Enalapril
d) These are contra-indicated in diabetic patients
Answer: Omission of prior diuretic dose decreases the risk of postural hypotension
Explanation:
ACE converts angiotensin I produced by the body to angiotensin II in the blood.
ACE inhibitors are effective for control of blood pressure, congestive heart failure, and prevention of stroke and hypertension, or diabetes-related kidney damage.
Except for captopril and lisinopril, ACE inhibitors are inactive until they are converted to an active form in the body.
Lisinopril is longer acting the Enalapril.
- Thalidomide can be used in all of the following conditions except
a) Behcet’s syndrome
b) HIV associated peripheral neuropathy
c) HIV associated mouth ulcers
d) Erythema nodosum leprosum
Answer: HIV associated peripheral neuropathy
Explanation:
Clinical uses of thalidomide:
Erythema nodosum leprosum
Cutaneous lupus erythematosus
AIDS related aphthous ulcers
AIDS related wasting syndrome
Multiple myeloma
Rheumatoid arthritis
Ankylosing spondylitis
Crohn’s disease
Bechet’s syndrome
Side effects of thalidomide use:
Terato-genicity
Peripheral neuropathy
Deep vein thrombosis
- In metabolism of xenobiotics all of the following reactions occur in phase one except
a) Oxidation
b) Reduction
c) Conjugation
d) Hydrolysis
Answer: Conjugation
Explanation:
Drug metabolism: Biotransformation of drugs
Phase-I:
Oxidation, Reduction, Hydrolysis, Cyclization and de-Cyclization
Phase-II (Conjugation reaction)
Methylation, sulfation, Acetylation and Glucuronidation
- Which of the following statements regarding acarbose is false?
a) It acts by inhibiting the enzyme alpha glucosidase
b) It reduces both pre and post prandial hyperglycemia
c) It decreases the progression of impaired glucose tolerance to overt diabetes mellitus
d) It reduces fibrinogen level
Answer: It reduces both pre and post prandial hyperglycemia
Explanation:
Acarbose is a glucosidase inhibitor and thus prevents the pos-prandial rise in plasma glucose.
Acarbose reduces the progression of type II DM in patients with impaired glucose tolerance.
- Cephalosporin that does not require dose reduction in patient with any degree of renal impairment is
a) Cefuroxime
b) Cefoperazone
c) Ceftazidime
d) Cefotaxime
Answer: Cefoperazone
Explanation:
All cephalosporins are excreted through kidney except Cefoperazone, Cefopiramide and Ceftriaxone which are excreted mainly through bile.
- Which of the following drugs is not an alkylating agent?
a) Cyclophosphamide
b) Busulfan
c) 5-fluorouracil
d) Melphalan
Answer: 5-fluorouracil
Explanation:
Alkylating agents used in the chemotherapy of neoplastic diseases:
Busulfan
Cyclophosphamide
Chlorambucil
Ifosfamide
Melphalan
- Ifosfamide belongs to which group of anticancer drugs
a) Alkylating agents
b) Anti-metabolites
c) Mitotic inhibitors
d) Topoisomerase inhibitors
Answer: Alkylating agents
Explanation:
Alkylating agents used in the chemotherapy of neoplastic diseases:
Busulfan
Cyclophosphamide
Chlorambucil
Ifosfamide
Melphalan
- All of the following drugs are used as immuno-suppressants except
a) Glucocorticoids
b) Cyclosporin
c) Cephalosporin
d) Azathioprine
Answer: Cephalosporin
Explanation:
Immuno-suppressants:
Glucocorticoids
Antibodies
Calcineurin inhibitors-Tacrolimus and cyclosporine
Anti-proliferative drugs- Azathioprine, Cyclophosphamide, Chlorambucil, Methotrexate, Mycophenolate, Mofetil