Correct Answer c chlorothiazide D

• 
  A Withdrawal symptoms are less prolonged than with morphine
  
• 
  B It binds to opioid and non opioid receptors Correct Answer
  
• 
  C It has a lower bioavailability than morphine
  
• 
  D Half life of methadone 12-24hrs
  

Explanation

Methadone is well absorbed from the GIT tract. Its bioavailability far exceeds that of morphine. It binds to non opioid receptors including NMDA and monoaminergic reuptake receptors. These receptor properties may explain methadone's ability to treat chronic pain and cancer patients when regular opioids have failed. Withdrawl symptoms following an abrupt stopping of methadone produces milder but more prolonged symptoms than morphine withdrawl. It has a long half life of 25-52hrs.

Question 37

Regarding ketamine, which of the following statements is correct?
Your answer was correct

• 
  A It can cause agitation and an emergence phenomina in children Correct Answer
  
• 
  B It is a bronchoconstrictor
  
• 
  C It increases respiratory rate initially
  
• 
  D It has no cardiovascular effects
  

Explanation

Ketamine is closely related to phencyclidine. It produces a dissociative amnesia anaesthetic state characterized by catatonia, amnesia, and analgesia without the loss of consciousness (hypnosis). It bonds to the NMDA receptor. It stimulates the cardiovascular system (+inotropy) via the central sympathetic nervous system. It causes a decrease in respiratory rate but preserves reflexes. It causes an increase in blood flow to the brain, brain oxygen consumption and intracranial pressure. It cause bronchodilation and prevents histamine release. Side effects include agitation and an emergence phenomenon in children

Question 38

Regarding dextropropoxyphene, which of the following statements is false?
Your answer was correct

• 
  A It is structurally similar to methadone
  
• 
  B It should never be used in patients with renal failure Correct Answer
  
• 
  C It produces greater pain relief when used with paracetamol
  
• 
  D It has no anti-inflammatory properties
  

Explanation

Dextropropoxyphene is a centrally acting, synthetic opioid analgesic structurally related to methadone. Combination with paracetaomol produces extra pain relief but no anti-inflammatory actions. The potency of the drug is about two thirds that of codeine. In patients with renal failure it should be used with caution as since higher concentration or delayed administration may occur

Question 39

Regarding opioid agonists and antagonists, which is incorrect?
Your answer was correct

• 
  A Codeine is a strong opioid agonist Correct Answer
  
• 
  B Naloxone is a pure antagonist
  
• 
  C Nalmefene is available only in IVI preperation
  
• 
  D Buprenorphine is an agonist-antagonist opioid
  

Explanation

Codeine is a partail agonist. It is less efficacious than morphine. It can antagonize strong agonists.

Buprenorphine is a partial mu agonist and a kappa antagonist.

Naloxone and naltexone are pure antagonists.

Nalmefene, the newest of the opioid antagonists is only available in IVI preperation.

Question 40

Regarding ibuprofen, select the correct answer.

• 
  A It causes more gastric side effects than aspirin Your Answer
  
• 
  B It has a low bioavailability
  
• 
  C It is a non selective COX inhibitor Correct Answer
  
• 
  D It is not effective in closing the patent ductus arteriosis in the preterm infant
  

Explanation

Ibuprofen is more than 99% protein bound, is rapidly cleared and has a terminal half-life of 1-2hrs. It is a reversible inhibitor of COX1 and COX 2. GIT irritation and bleeding do occur, but with less frequency than aspirin. Its bioavailability is 50-73%. It may cause closure of the patent ductus arteriosis

Question 41

Regarding dextropropoxyphene, which of the following statements is correct?
Your answer was correct

• 
  A When combined with paracetamol is a strong anti inflammatory
  
• 
  B Overdose causes death from hepatotoxicity
  
• 
  C It is structurally related to methadone Correct Answer
  
• 
  D It is a strong opiod
  

Explanation

Dextropropoxyphene is a centrally acting, synthetic opioid analgesic structurally related to methadone. Combination with paracetaomol produces extra pain relief but no anti-inflammatory actions. The potency of the drug is about two thirds that of codeine

Question 42

Regarding paracetamol, which of the following statements is correct?
Your answer was correct

• 
  A It is hydrophillic
  
• 
  B It is only given orally
  
• 
  C It is highly protein bound
  
• 
  D It doesn't cause hyperuricaemia Correct Answer
  

Explanation

Paracetamol can be given orally, IVI and rectally. It is slightly protein bound. Half-life is 2-3hrs and is relatively unaffected by renal function

Question 43

Regarding paracetamol toxicity which of the following statements is correct?
Your answer was not correct

• 
  A Toxicity is related to glutothione consumption Correct Answer
  
• 
  B Enhanced with cimetidine
  
• 
  C Toxic metabolite is due to sulphanation Your Answer
  
• 
  D N-acetylation produces the toxic metabolite
  

Explanation

Acetominophe is conjugated to harmless glucuronide and sulfate metabolites when taken at normal doses. If abnormal doses are taken the metabolic pathways are overwhelmed and a P450-dependant system converts some of the drug to NAPQI, a reactive intermediate. NAPQI is conjugated with glutathione to a third harmless product if the stores of glutathione are adequate. If the stores are exhausted, the NAPQI combines with essential hepatic cell proteins causing hepatic cell death. Administration of other sulhydryl donors e.g. acetylcysteine may be life saving. Enzyme inducers may increase acetominophen toxicity because they increase phase I metabolism more than phase II thus resulting in increased production of NAPQI

Question 44

Redarding allopurinol, which of the following statements is correct?
Your answer was correct

• 
  A It is metabolised by xanthine oxidase Correct Answer
  
• 
  B It has no side effects
  
• 
  C It is useful in acute gout
  
• 
  D It has a low oral bioavailability
  

Explanation

Allopurinol is not useful in acute attacks but rather the period between attacks of gout. It can cause a gouty arthritis when initially started.

You need to take colchicine and NSAIDS concurrently. It has a bioavailability of 80%, its half life 1-2 hrs and is metabolized by xanthine oxidase. The resulting compound, alloxanthine, retains the capacity to inhibit xanthine oxidase and has a long enough duration of action so that allupiranol can be given once a day. Side effects include GIT intolerance, depression of bone marrow, hepatic toxicity and renal disease.

Question 45

What effects do kappa receptors mediate?

 
Your answer was correct

• 
  A Slows gastrointestinal transit Correct Answer
  
• 
  B Antidepressant effects
  
• 
  C Physical dependence
  
• 
  D Respiratory depression
  

Explanation

Kappa receptors mediate supraspinal analgesia, spinal analgesia, psychotomimetic effects, slow gastrointestinal transit, inhibit ADH release, cause miosis, sedation and dysphoria

Mu receptors - decreases respiration, supraspinal and spinal analgesia, sedation, slow GIT transit, modulation of hormone and neurotransmitter release, causes physical dependence, miosis and euphoria, 

Delta receptors - supraspinal and spinal analgesia, and modulation of hormone and neurotransmitter release

Question 46

Why is methadone is used in the treatment of narcotic addiction?
Your answer was correct

• 
  A It does not produce constipation
  
• 
  B It is a phenylpiperadine class narcotic agonist
  
• 
  C It produces a short withdrawl when ceased
  
• 
  D It produces predictable effects when given orally Correct Answer
  

Explanation

Methadone produces a milder but longer withdrawal when stopped than morphine.  It has proven to be beneficial in treating chronic pain when morphine has failed. Pethidine is a phenylpiperadine class narcotic agonist. A side effect of methadone is constipation

uestion 47

A high degree of tolerance can be expected to all these effects of morphine EXCEPT?
Your answer was not correct

• 
  A Analgesia
  
• 
  B Miosis Correct Answer
  
• 
  C Nausea Your Answer
  
• 
  D Cough supression
  

Explanation

Tolerance does not occur with miosis, constipation and respiratory depression

Question 48

Regarding ketamine, which of the following statements is correct?
Your answer was correct

• 
  A It is a cardiovascular stimulant via a central mechanism Correct Answer
  
• 
  B It causes a brief period of increased respiratory rate
  
• 
  C It decreases cerebral blood flow
  
• 
  D It possesses no analgesic properties
  

Explanation

Ketamine is closely related to phencyclidine. It produces a dissociative amnesic anaesthetic state characterized by: catatonia, amnesia, and analgesia without the loss of consciousness (hypnosis). It binds to the NMDA receptor. It stimulates the cardiovascular system (+inotropy) via the central sympathetic nervous system. It causes a decrease in respiratory rate but preserves reflexes. It causes an increase in blood flow to the brain, brain oxygen consumption and intracranial pressure. It cause bronchodilation and prevents histamine release. Side effects include agitation and an emergence phenomenon in children

Question 49

Regarding aspirin, which of the following statements is correct?
Your answer was correct

• 
  A It has a pKa of 6.5
  
• 
  B In moderate doses it increases respiratory rate Correct Answer
  
• 
  C It is a reversible inhibitor of cyclo-oxygenase
  
• 
  D Alkalinising the urine will decrease excretion
  

Explanation

Aspirin has a pKa of 3.5. It is an irreversible inhibitor of cyclo-oxygenase and, at moderate doses, causes an increased respiratory rate. In higher doses a respiratory alkalosis occurs followed by a metabolic acidosis. Alkalinising the urine will increase excretion of aspirin. Aspirin effects last the life of platelets which is 8-10 days. Aspirin demonstrates capacity limited clearance at low doses. I.e. saturable elimination at low doses

Question 50

Which pathway produces the toxic metabolite in paracetamol overdose?
Your answer was not correct

• 
  A Conjugation with glutathione Your Answer
  
• 
  B N-hydroxylation Correct Answer
  
• 
  C Glucoronidation
  
• 
  D Sulfation
  

Explanation

N-hydroxylation forms the NAPQI toxic `metabolite, which leads to liver failure.

Question 51

Regarding cimitidine, which of the following statements is correct?
Your answer was not correct

• 
  A It blocks both H1 and H2 receptors
  
• 
  B T1/2 is 22 hours
  
• 
  C It inhibits cytochrome P450 Correct Answer
  
• 
  D It never causes gynaecomastia Your Answer
  

Explanation

Cimetadine blocks H2 receptors and not H1. Half life is 1.9hrs. Bioavailability of approximately 62%. VD 70L/Kg.  Gynaecomastia is one of the many side effects (others include mental state changes, and galactorrhea in women; impotence in men).  They rarely cause blood dyscrasias

Question 52

Regarding cisapride, which of the following statements is correct?
Your answer was not correct

• 
  A It slows gastric emptying Your Answer
  
• 
  B It delays oesophageal clearance
  
• 
  C It raises lower oesophageal sphincter pressure Correct Answer
  
• 
  D It increases pancreatic secretions
  

Explanation

Cisapride is a 5-HT4 agonist and was used in the treatment of gastro-oesophageal reflux and motility disorder. Due to its association with increased cardiovascular events that were attributed to the inhibition of cardiac hERG K channels, which resulted in QT prolongation in patients, it is only prescribed in the USA for compassionate reasons

Question 53

Regarding metoclopramide, which of the following statements is correct?
Your answer was correct

• 
  A It decreases the tone of the lower oesophageal sphincter
  
• 
  B It increases gastric emptying Correct Answer
  
• 
  C It decreases ileal peristalsis
  
• 
  D It is a dopamine agonist
  

Explanation

Metoclopramide is a prokinetic that aids gastric emptying and promotes peristalsis. It is a dopamine antagonist. It also increases lower oesophageal sphincter tone

Question 54

Which of the following drugs is not an antiemetics?
Your answer was correct

• 
  A Ondansetron
  
• 
  B Diphenoxylate Correct Answer
  
• 
  C Dexamethasone
  
• 
  D THC
  

Explanation

Diphenoxylate is a prescription opiod agonist that has no analgesic properties in standard doses. However in higher doses there are CNS effects and this leads to dependence. Atropine is added in small doses to discourage overdose. The anticholinergic properties of atropine may contribute to the antidiarrheal action. Chemicals which work at the chemoreceptor trigger zone are ACH, serotonin, dopamine, substance P and THC

Question 55

Insulin causes which of the following effects?
Your answer was correct

• 
  A A decrease in lipolysis in liver
  
• 
  B A decrease glycogenesis in liver
  
• 
  C An increase in glycogen synthesis in liver Correct Answer
  
• 
  D A decrease in lipolysis in skeletal muscle
  

Explanation

Insulin is an anabolic steroid. Lipogenesis occurs, as does muscle development, glycogen synthesis and storage in liver and muscle and triglyceride synthesis and storage in the adipose tissue

Question 56

Regarding metformin, which of the following statements is correct?
Your answer was not correct

• 
  A It is a sulphonylurea
  
• 
  B It causes a mild lactic acidosis Your Answer
  
• 
  C It is similar to chlorpropamide
  
• 
  D It does not require functioning pancreatic B cells for its action Correct Answer
  

Explanation

Metformin is a biguanide and can cause a significant lactic acidosis (and is contraindicated in the presence of renal or liver disease or condition which result in tissue anoxia). Chlorpropamide is a sulfonylurea and a different class of hypoglcaemics. Metformin is an insulin-sparing agent and does not increase weight gain or cause hypoglycaemia in such patients. Their blood glucose lowering action does not depend on the presence functioning pancreatic B cells.

Question 57

Insulin causes all of the following EXCEPT?
Your answer was not correct

• 
  A Decrease in glycogenolysis in the liver
  
• 
  B Increase in glycogen synthesis in the liver Your Answer
  
• 
  C Increase in lipolysis in the liver Correct Answer
  
• 
  D Inhibition of gluconeogenesis
  

Explanation

Insulin is an anabolic steroid. Lipogenesis occurs as does muscle development, glycogen synthesis and storage in liver and muscle,  triglyceride synthesis and storage in adipose tissue.In the liver there is a decreased glucose output due to decreased gluconeogenesis, increased glycogen synthesis and increased glycolysis. (This is an intermediate effect of insulin)

Question 58

Which of the following is NOT an action of glucagon?
Your answer was not correct

• 
  A Stimulates gluconeogenesis
  
• 
  B Smooth muscle contraction Correct Answer
  
• 
  C Positive inotrope
  
• 
  D Positive chronotrope Your Answer
  

Explanation

Glucagon raises blood sugar at the expense of stored hepatic glucagon. It does not have any effect on stored skeletal glucagon because of a lack of receptors on the skeletal muscle. Pharmacological amounts of glucagon cause release of insulin form normal pancreatic b cells, cathecolamines form pheochromocytoma and calcitonin from medullary carcinoma cells

Question 59

Which of the following has the most potent mineralcorticoid activity?
Your answer was correct

• 
  A Cortisol
  
• 
  B Cortisone
  
• 
  C Aldosterone Correct Answer
  
• 
  D Corticosterone
  

Explanation

Question 60

Which of the following has the most potent mineralocorticoid activity?

• 
  A Hydrocortisone Correct Answer
  
• 
  B Prednisolone
  
• 
  C Methylprednisolone
  
• 
  D Dexamethasone Your Answer
  

Explanation

Relative mineralocorticoid potencies:

Hydrocortisone 1

Fludrocortisone 250

Cortisone 0.8

Prednisolone 0.3

Methylprednisolone 0.25

Dexamethasone 0

Question 61

With regard to oral hypoglycaemics which of the following statements is correct?
Your answer was not correct

• 
  A Tolbutamide and glipizide are sulphonylureas Correct Answer
  
• 
  B Chlorpropramide has a half life of 4-6 hours
  
• 
  C Metformin is more effective once weight is controlled Your Answer
  
• 
  D Lactic acidosis is more common with metformin than phenformin
  

Explanation

Lactic acidosis is more common with phenformin and, as a result, has been taken off the market. It had a mortality of 50% once lactic acid developed. Metformin is not more effective once weight is controlled. Chlorpropramide has a half life of 32hrs. Sulphonylureas (SU) can cause hypoglycaemia where as the buguanides (B) don’t. Metformin does not require functioning pancreatic beta cells for its action

SU= tolbutamide, tolazamide, acetohexamide, chlorpropamide, glyburide, glipizide, glimepiride.

B= metformin, phenformin, buformin

Question 62

With regards to glucocorticoids, which of the following statements is correct?
Your answer was not correct

• 
  A Dexamethasone has a short half life
  
• 
  B Prednisone is 4 times more potent than hydrocortisone Correct Answer
  
• 
  C Fludrocortisone can only be given intravenously Your Answer
  
• 
  D Methylprednisolone has no mineralocorticoid effects
  

Explanation

Fludrocortisone can be given orally, as an injection and topical. Methylprednisolone has salt retaining properties (only slight) and dexamethasone has a long half life of 36-54hrs. Dexamethasone has the highest anti-inflammatory properties of the group. Prednisone is 4 times the potency of hydrocortisone and prednisolone is 5 times the potency of hydrocortisone

Question 63

Which of these drugs has a different intracellular signalling mode of action compared to the others?
Your answer was correct

• 
  A Insulin Correct Answer
  
• 
  B Glucagon
  
• 
  C ACTH
  
• 
  D PTH
  

Explanation

Insulins mode of action involves tyrosine kinase A. The rest of the drugs involve a secondary mechanism camp

Question 64

Regarding histamine, which of the following statements is correct?
Your answer was not correct

• 
  A It decreases smooth muscle spasm Your Answer
  
• 
  B It causes vasoconstriction and therefore hypertension
  
• 
  C It increases myocardial contractility Correct Answer
  
• 
  D It has no effect on local edema
  

Explanation

Histamine causes bronchospam, vasodilatation and hypotentsion. Direct cardiac effects of histamine include both increased contractility and increased pacemaker rate-mediated activity, chiefly by H2. It also causes local edematous wheals following a type 1 hypersensitivity reaction

Question 65

Antihistamines have significant effects at all of the following receptors EXCEPT?
Your answer was not correct

• 
  A Muscarinic
  
• 
  B Serotonin
  
• 
  C Nicotinic Correct Answer
  
• 
  D Alpha adrenergic Your Answer
  

Explanation

The first generation H1 receptor antagonists have many actions not ascribable to blockade of its actions of histamine. Due to the similarity of its structure to other drugs that have effects on other receptors, antihistamines have effects on muscarinic, alpha adrenoceptors, serotonin, and local anaesthetic receptor sites. Some of these actions are of therapeutic value and some are undesirable

Question 66

Regarding erythromycin, which of the following statements is correct?
Your answer was not correct

• 
  A It is effective against Campylobacter jejuni Correct Answer
  
• 
  B It is predominantly renally excreted
  
• 
  C It is a cell wall inhibitor
  
• 
  D It is bacteriostatic only Your Answer
  

Explanation

Erythromycin is excreted mostly in bile and feces. Only 5% is excreted in the urine. It inhibits protein synthesis. It is both bacteriocidal and bacteriostatic

Question 67

Which of the following drugs causes hypoprothrombinaemia & bleeding disorders?
Your answer was correct

• 
  A Cefuroxime
  
• 
  B Cefaclor
  
• 
  C Cefotetan Correct Answer
  
• 
  D cefoxitin
  

Explanation

Cephalosporins containing a methylthiotetrazole group can frequently cause hypoprothrombinaemia and bleeding disorders preventable by administration of vitamin K twice weekly (10mg). Such cephalosporins include cefamandole, cefmetazole, cefotetan and cefoperazone. These dugs can also cause a severe disulfiram like reaction thus alcohol should be avoided during treatment with these cephalosporins. All the above are second generation cephalsporins. Cefuroxime, cefaclor and cefoxitin do not contain a methylthiotetrazole (MTT) group.

Question 68

Regarding Penicillin G, which of the following statements is correct?