Pharmacology

Flutamide A nonsteroidal drug having specific antiandrogenic, but no other hormonal activity. Its active metabolite 2-hydroxyflutamide competitively blocks androgen action on accessory sexorgans as well as on pituitary-increases LH secretion by blocking feed back inhibition. Plasma testosterone levels increase in males which partially overcome the direct antiandrogenic action of flutamide. Palliative effect may occur in advanced prostatic carcinoma but it is better used in conjunction with a GnRH agonist (to suppress LH and testosterone secretion) or after castration. Along with oral contraceptives it has been tried in female hirsutism. Though gynaecomastia and breast tenderness occur frequently, libido and potency are largely preserved. Reports of liver damage have restricted its use.

2] Morphine cannot be used in all the following conditions except:

1. Head injury.

2. Asthma.

3. Hypothyroidism.

4. Diabetes.

Ans : 4 ( Pg - 423 /Tripathi )

Morphine is a drug of emergency, but due care has to be taken in its use.

1. Infants and the elderly are more susceptible to the respiratory depressant action of morphine.

2. It is dangerous in patients with respiratory insufficiency (emphysema, pulmonary fibrosis, cor pulmonale), sudden deaths have occurred.

3. Bronchial asthma: Morphine can precipitate an attack by its histamine releasing action.

4. Head injury: morphine is contraindicated in patients with head injury. Reasons are

(a) By retaining CO2 it increases intracranial tension which will add to that caused by head injury itself.

(b) Even therapeutic doses can cause marked respiratory depression in these patients.

(c) Vomiting, miosis and altered mentation produced by morphine interfere with assessment of progress in head injury cases.

5. Hypotensive states and hypovolemia exaggerate fall in BP due to morphine.

6. Undiagnosed acute abdominal pain: morphine can aggravate certain conditions, e.g. diverticulitis, biliary colic, pancreatitis. Inflamed appendix may rupture. Morphine can be given after the diagnosis is established. Pentazocine, buprenorphine are less likely to aggravate biliary spasm.

7. Elderly male: chances of urinary retention are high.

8. Hypothyroidism, liver and kidney disease patients are more sensitive to morphine.

9. Unstable personalities: are liable to continue with its use and become addicted.

3] Clinically significant drug interaction occurs between pyridoxine and all the following drugs except:

1. Isoniazid.

2. Cyclosporine.

3. Levodopa.

4. Hydralazine.

Ans : 2 { Pg - 823 / KD Tripathi }

1. Isoniazid reacts with pyridoxal to form a hydrazone, and thus inhibits generation of pyridoxal phosphate. Isoniazid also combines with pyridoxal phosphate; high doses interfere with the coenzyme function of the latter. Due to formation of hydrazones the renal excretion of pyridoxine compounds is increased. Thus, isoniazid therapy produces a pyridoxine deficiency state.

2. Hydralazine, cycloserine and penicillamine also interfere with pyridoxine utilization and action.

3. Oral contraceptives reduce pyridoxal phosphate levels in some women.

4. Pyridoxine, by promoting formation of dopamine from levodopa in peripheral tissues, reduces its availability in the brain, abolishing the therapeutic effect in parkinsonism.

5. 4-deoxypyridoxine is a vit B6 antagonist.

Deficiency symptoms Deficiency of vit B6 usually occurs in association with that of other B vitamins. Symptoms ascribed to pyridoxine deficiency are-seborrheic dermatitis, glossitis, growth retardation, mental confusion, lowered seizure threshold or convulsions (due to fall in brain GABA levels), peripheral neuritis and anaemia.

4] All of the following statements about an alpha glucosidase inhibitor are true except:

1. Reduces intestinal absorption of carbohydrates.

2. Effective in both type 1 and 2 diabetes mellitus.

3. Hypoglycemia is a common and serious side effect.

4. Can be used with other oral hypoglycemic agents.

Ans : 3 [ Pg - 252 / KDT 5th edition ]

Acarbose It is a complex oligosaccharide which reversibly inhibits a-glucosidases, the final enzymes in the digestion of carbohydrates in the brush border of small intestine mucosa. It slows down and decreases digestion and absorption of polysaccharides and sucrose: postprandial glycaemia is reduced without increasing insulin levels. Regular use tends to lower Hb Ale, body weight and serum triglyceride. These beneficial effects, though modest, have been confirmed in several studies.

Acarbose is a mild antihyperglycaemic andnot a hypoglycaemic: may be used as an adjuvant to diet (with or without a sulfonylurea) in obese diabetics. Dose 50-100 mg TDS taken at the beginning of each major meal. It is minimally absorbed, but produces flatulence and loose stool in about 50% patients due to fermentation of unabsorbed carbohydrates.

5] Which one of the following statements about biguanides is not true?

1. Do not stimulate insulin release.

2. Decrease hepatic glucose production.

3. Renal dysfunction is not a contraindication for their use.

4. Can be combined with sulfonylureas.

Ans : 3 ( Pg - 249 / KDT )

In addition to general restrictions for use of oral hypoglycaemics (see below), biguanides are contraindicated in hypotensive states, cardiovascular, respiratory, hepatic and renal disease and in alcoholics because of increased risk of lactic acidosis.

6] Which of the following statements is not true about tacrolimus?

1. It is a macrolide antibiotic.

2. It is indicated for the prophylaxis of organ transplant rejection.

3. Glucose intolerance is a well recognized side effect.

4. It can be safely administered with any nephrotoxic drug.

Ans : 1 [ KDT / Pg- 778 ]

Tacrolimus (FKS06) It is a newer immunosuppressant chemically different from cyclosporine but having the same mechanism of action and is -100 times more potent. It binds to a different cytoplasmic protein labelled 'FKBP', but the subsequent steps are the same, Le. inhibition of helper T cells via calcineurin.

Tacrolimus is administered orally as well as by iv. infusion, exhibits a longer hl., (12-24 hr), and has the same therapeutic application as well as toxicity profile. It is particularly valuable in liver transplantation because its absorption is not dependent on bile. Because of more potent action it is also suitable for suppressing acute rejection that has set in. It causes less hypertension, hirsutism and gum hyperplasia than cyclosporine, but is more likely to precipitate diabetes, cause neurotoxicity, alopecia and diarrhoea.

7] Sympathomimetic drugs are useful in the therapy of all of the following conditions except:

1. Acute decompensated heart failure.

2. Hypotension.

3. Hypertension.

4. Erectile dysfunction.

Ans : 3 (Pg 112/KDT 5th)

Transient restlessness, palpitation, anxiety, tremor, pallor may occur after s.c./i.m. injection of Adr.

Marked rise in BP leading to cerebral hemorrhage ventricular tachycardia/fibrillation are the hazards of large doses or inadvertent iv. injection.

Adr is contraindicated in hypertensive, hyperthyroid and angina patients.

It should not be given during anesthesia with halothane (risk of arrhythmias) and to patients receiving beta blockers (marked rise in BP can occur).

8] Which of the following is not an adverse effect of chronic amiodarone therapy:

1. Pulmonary fibrosis.

2. Hypothyroidism.

3. Hyperthyroidism.

4. Systemic lupus erythematosus.

Ans : 4 (Harrison /15th-- pg 1306 \table)

9] In which of the following phases of clinical trial of drugs ethical clearance is not required?

1. Phase I

2. Phase II.

3. Phase III.

4. Phase IV.

ANS : 4 ( in case of clinical trials) \ 1 ( In case of preclinical animal trials)

10] Which of the following is not a nucleoside reverse transcriptase inhibitor?

1. Zalcitabine.

2. Lamivudine.

3. Nevirapine.

4. Didanosine.

Ans : 3 [ KDT /Pg 730]

11] Which of the following antimicrohials has antipseudomonal action:

1. Cefpodoxime proxetil.

2. Ceforanide.

3. Cefotetan.

4. Cefoperazone.

Ans : 4 ( KDT / Pg 665)

12] Which of the following statements is not true regarding sulfonamides:

1. Sulfasalazine is absorbed well from gastro intestinal tract.

2. Crystalluria can occur with sulfonamide administration.

3. Sulfonamide administration to newborn may cause kernicterus.

4. Sulfonamides are of value in treatment of infections due to Nocardia species.

Ans : 1 ( KDT / Pg- 620 )

13] Which of the following does not bind to GABA receptor chloride channels?

1. Ethanol.

2. Alphaxolone.

3. Zolpidem.

4. Buspirone.

Ans : 4 { KDT / Pg : 401}

14] A patient of peptic ulcer was prescribed ranitidine and sucralfate in the morning hours. Why is this combination incorrect:

1. Ranitidine combines with sucralfate and prevents its action.

2. Combination of these two drugs produces serious side effects like

agranulocytosis.

3. Ranitidine decreases the gastric pH so sucralfate is not able to act.

4. Sucralfate inhibits absorption of ranitidine.

Ans : 4 [ CMDT 2001 / Pg- 607 ]

Note : Ranitidine increases gastric pH & so #3 is wrong ( low pH=acidic)

15] A 30 year old pregnant woman developed tuberculosis. Which of the following antitubercular drugs should not be used:

1. INH.

2. Rifampicin.

3. Streptomycin.

4. Ethambutol.

Ans : 3 ( Pg 681 / KDT )

16] Which of the following fluoroquinolones does not require dose adjustment in a patient with creatinine clearance of <50 mg/minute ?

1. Ciprofloxacin.

2. Trovafloxacin.

3. Lomefloxacin.

4. Sparfioxacin.

Ans : 2 [ Pg 879 / Harrison ]

Note: Since Trovafloxacin causes liver toxicity , it is withdrawn from the market

17] Patients suffering from multidrug resistant tuberculosis can be treated with all the following drugs except:

1. Tobramycin.

2. Amikacin.

3. Ciprofloxacin.

4. Clarithromycin.

Ans : 1 ( KDT /Pg 703)

18] All the following statements regarding interactions of levodopa are correct except:

1. In parkinsonism, phenothiazines reduce its efficacy.

2. It is a prodrug.

3. Pyridoxine reduces effect of levodopa in parkinsonism.

4. Domperidone blocks levodopa induced emesis and its therapeutic potential.

Ans : 4 [ Pg 385 /KDT ]

19] Which of the following actions is ascribed to delta type of opioid receptors?

1. Supraspinal analgesis.

2. Respiratory depression.

3. Euphoria.

4. Reduced intestinal motility.

Ans : 1 ( Pg : 429 / KDT)

20] BAL is useful in treating poisoning due to all except:

1. Lead.

2. Organic mercury.

3. Cadmium.

4. Arsenic.

Ans : 3 [ Pg 813 / KDT ]

Note: BAL is contraindicated in cadmium poisoning as it can form more lethal metabolites!!!

21] A 15-year-old boy with epilepsy on treatment with combination of vaiproate and phenytoin has good control of seizures. Levels of both drugs are in the therapeutic range. All of the following adverse effects can be attributed to vaiproate except:

1. Weight gain of 5 kg.

2. Serum alanine aminotransaminase 150 LU/L.

3. Rise in serum ammonia level by 20 j

4. Lyrnphadenopathy.

Ans : 4 [ Pg 2364 /Harrison 15th ]

22] A known sputum positive pulmonary tuberculosis patient currently on INH. rifampicin, pyrizinamide and ethambutol is found to be HIV positive. His CD4 count was 1004tL and viral load was more than 50.000 copies/mi. Which of the following antiretroviral drugs should be avoided:

1. Indinavir.

2. Lamivudin.

3. Ritonavir.

4. Efavirenz.

Ans : 2 { Pg 1907 / Harrison 15th )

23] All of the following are true about amiodarone induced thyroid dysfunction except:

1. Hyperthyroidism is common in iodine deficient areas.

2. Hypothyroidism is more common in men.

3. Amiodarone inhibits deiodinase activity.

4. Amiodarone therapy is associated with initial reduction of serum T4 levels.

Ans : 2 [ Pg 518 / KDT-Table]

24] All of the following may be used in pregnancy associated hypertension except:

1. Nifedipine.

2. Captopril.

3. Methyldopa.

4. Hydralazine.

Ans : 2 ( Pg 466 /KDT )

25] A post-operative patient developed septicemia and was empirically started on combination chemotherapy by’ a new resident doctor. However, when the patient did not respond even after 10 days of antibiotics treatment, the review of the charts was done. It was found that the resident doctor had started the combination of antibiotics which was mutually antagonistic in action. Which one of the following is the most likely combination that was given?

1. Vancomycin and Amikacin.

2. Cephelexin and Gentamicin.

3. Ampicillin and Chloramphenicol.

4. Ciprofloxacin and Piperacillin.

Ans : ? 3

Note :

# When injectable tetracycline's are mixed with penicillin's , it leads to their inactivation. < KDT-Pg672>

# Ureidopenicillins inactivate amino glycosides when mixed in the same bottle.<Kaplan>

# Carbeniccilins & Ticarcillin Inactivates amino glycosides when mixed in the same syringe < Kaplan >

26] Drug implicated for prolonging QT interval in a premature baby is:

1. Domperidone.

2. Metoclopramide.

3. Cisapride.

4. Omeprazole.

Ans : 3 { Pg 605 / KDT }

27] Which of the following is the best indication for propofol as an intravenous induction agent?

1. Neurosurgery.

2. Day care surgery.

3. Patients with coronary artery disease.

4. In neonates.

Ans : 2 [ KDT / Pg- 343]

Note: Propofol is contraindicated in children

28] Which of the following volatile anesthetic agents should be preferred for induction of anesthesia in children?

1. Enflurane.

2. Isoflurane.

3. Sevoflurane.

4. Desfiurane.

Ans : 3 ( KDT / Pg 341)

29] A highly ionized drug:

1. Is excreted mainly by the kidneys.

2. Crosses the placental barrier easily.

3. Is well absorbed from the intestine.

4. Is highly protein bound.

Ans : 1 < Pg 26/KDT >