Your answer was not correct

• 
  A Hypernatraemia is not reported Your Answer
  
• 
  B It has good penetration to the eye
  
• 
  C 100 000u intrathecally can cause seizures Correct Answer
  
• 
  D 50% of people who claim allergy will have an allergic reaction on further exposure
  

Explanation

Hypernatraemia can occur if penicillin is given in very high doses and patients have renal or cardiovascular diseases. Seizures occur in patients with renal failure who are given high dose penicillin. There is a 5-10% chance of a second reaction. Only amoxicillin can be given with food to prevent the drug binding with the food and not being absorbed or gastric acid neutralizing the drug

Question 69

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

• 
  A It should be avoided in HIV patients
  
• 
  B It is an antiretroviral agent
  
• 
  C It is a protease inhibitor
  
• 
  D It can cause iatrogenic diabetes Correct Answer
  

Explanation

Pentamidine is an antirpotozoal drug. It interferes with nuclear metabolism. It can be toxic to the beta cells of the pancreas and cause diabetes. It is used as an agent for prophylaxis against pneumocystosis in immune compromised patients e.g. HIV patients

Question 70

Which antibiotic is a cell wall inhibitor?
Your answer was not correct

• 
  A Erythromycin Your Answer
  
• 
  B Streptomycin
  
• 
  C Vancomycin Correct Answer
  
• 
  D Gentamycin
  

Explanation

Cephalosporins and penicillins are also cell wall inhibitors

Question 71

Regarding cephalosporins, which of the following options is incorrect?
Your answer was not correct

• 
  A Cefaclor is a second generation cephalosporin
  
• 
  B 2nd generation cephalosporins have greater gram negative activity than first generation cephalosporins
  
• 
  C ceftriaxone has anti-pseudomonal activity Correct Answer
  
• 
  D Generally they have a wider spectrum of activity compared to pencillins due to beta-lactmase resistance Your Answer
  

Explanation

Only ceftazidine and cefoperazone has anti-pseudomonal activity

Question 72

Of the drugs listed, which inhibits cell membrane function?
Your answer was not correct

• 
  A Amikicin
  
• 
  B Erythromycin
  
• 
  C Vancomycin Your Answer
  
• 
  D Amphotericin B Correct Answer
  

Explanation

Amikacin inhibits the 30s ribosome subunit (protein synthesis). Erythromycin inhibits protein synthesis. Vancomycin inhibits cell wall synthesis

Question 73

Which of the following statements is true regarding penicillins?
Your answer was correct

• 
  A they do not cause hypernatremia
  
• 
  B they can cause seizures. Correct Answer
  
• 
  C 50% of people with a previous reaction will have another reaction
  
• 
  D Foods treated with tetracycline can cause reaction
  

Explanation

Hypernatraemia can occur if penicillin is given in very high doses and patients have renal or cardiovascular diseases. Seizures occur in patients with renal failure who are given high dose penicillin. There is a 5-10% chance of second reaction. Only amoxicillin can be given with food to prevent the drug binding with the food and not being absorbed or gastric acid neutralizing the drug

Question 74

Which of the following antibiotics is resistant to beta - lactamase?
Your answer was not correct

• 
  A Penicillin
  
• 
  B Piperacillin Your Answer
  
• 
  C Cloxacillin Correct Answer
  
• 
  D Amoxicillin
  

Explanation

Question 75

Which of the following drugs listed below is a cell wall inhibitor?

• 
  A Cephalosporin Correct Answer
  
• 
  B Tetracyclin
  
• 
  C Ciprofloxacin
  
• 
  D Gentamycin
  

Explanation

Question 76

Regarding trimethoprim, which of the following statements is incorrect?

• 
  A It is bacteriocidal Correct Answer
  
• 
  B It is synergistic with sulphonamides
  
• 
  C It causes folate synthesis disruption
  
• 
  D It is less toxic to humans than bacteria
  

Explanation

When trimethoprim is used in combination with a sulphonamide it is bacteriocidal

Question 77

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

• 
  A It is not nephrotoxic
  
• 
  B It decreases the effect of neuromuscular junction blocking drugs
  
• 
  C It enters cells by an oxygen dependent influx Correct Answer
  
• 
  D It has a large theraputic index
  

Explanation

Gentamycin is effective against gram positive and gram negative bacteria but not against anaerobes. It prevents protein synthesis of the bacteria. The drug is transported actively across the cell membrane into the cytoplasm by an oxygen dependent process. Many bacteria are resistant to gentamycin owing to the inability of gentamicin to penetrate the cell wall. This is overcome when a penicillin or vancomycin is added in combination. These inhibit cell wall synthesis allowing gentamicin to enter the bacteria; it is a bactericidal combination. Gram negative resistance is due to plasmid encoding aminoglycoside-modifying enzymes. It is both ototoxic and nephrotoxic. Gentamicin increases the effect of the NMB. Gentamicin has both a concentration dependent killing  and post antibiotic properties and a narrow therapeutic index.

Question 78

All of the following antibiotics inhibit nucleic acid synthesis except?
Your answer was correct

• 
  A Norfloxacin
  
• 
  B Rifampicin
  
• 
  C Sulfasalazine
  
• 
  D Chloramphenicol Correct Answer
  

Explanation

Norfloxacin inhibits DNA replication, trimethoprim blocks purine production, rifampicin blocks production of RNA and sulfasalazine is involved DNA blocking activities-although the process is not well understood

Question 79

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

• 
  A It is an antiviral drug
  
• 
  B It causes acute psychosis
  
• 
  C It potentiates dopaminergic function
  
• 
  D All of the above Correct Answer
  

Explanation

Amantadine blocks the M2 proton ion channel of the virus particle and inhibits uncoating of the viral RNA within infected host cells, thus preventing its replication. One of the side effects is that it produces insomnia and not sedation. It is active against influenza A only. Clinical manifestations of anticholinergic activity tend to be present in acute amantadine overdose. It is an antiviral drug that was by chance found to have antiparkinsonism properties; it may potentiate dopaminergic function by influencing the synthesis, release or uptake of dopamine

Question 80

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

• 
  A It acts to inhibit viral entry into cells Your Answer
  
• 
  B It is commonly given in doses of 10-20 mg TDS
  
• 
  C It is used to treat CMV
  
• 
  D It is a guanosine analogue Correct Answer
  

Explanation

Acyclovir is given in doses of 10-20mg/kg. It is not useful against CMV in vivo. It inhibits viral DNA synthesis and is administered via an oral or intravenous route. Oral bioavailability is low (15-20%) and is unaffected by food. Half life 2-3 hrs and excreted primarily by glomerular filtration and tubular secretion.

Question 81

Acyclovir is active against all the following viruses except?
Your answer was correct

• 
  A HSV
  
• 
  B CMV Correct Answer
  
• 
  C HZV
  
• 
  D Varicella
  

Explanation

In vitro testing shows some weak activity against CMV

Question 82

Regarding metronidazole which of the following statements is not true?
Your answer was not correct

• 
  A It inhibits alcohol dehydrogenase Correct Answer
  
• 
  B It causes a metallic taste in the mouth
  
• 
  C It is used to treat gardenella Your Answer
  
• 
  D It is useful against trichomonas vaginalis
  

Explanation

Metronidazole is an antiprotozoal drug with antibacterial activity against anaerobes. It is well absorbed after oral administration and readily penetrates the CSF. It produces a disulfiram like effect- the inhibition of aldehyde dehydrogenase and the accumulation of acetaldehyde

Question 83

Of the antiviral drugs listed, which one acts on reverse transcriptase?
Your answer was correct

• 
  A acyclovir
  
• 
  B zidovudine Correct Answer
  
• 
  C ganciclovir
  
• 
  D vidarabine
  

Explanation

Question 84

Regarding Zidovudine ( AZT), which of the following statements is correct?

• 
  A It is not well absorbed from the gut Your Answer
  
• 
  B It has a half life of 3.3 hrs Correct Answer
  
• 
  C It inhibits viral thymidine kinase
  
• 
  D It has no activity against retroviruses
  

Explanation

AZT is used to treat retroviral infections. It has a half life of 1-3hrs. AZT inhibits reverse transcriptase of HIV1/HIV2. Amantadine blocks the M2 proton ion channel of the virus particle and inhibits uncoating of the viral RNA within infected host cells, thus preventing its replication. AZT is well absorbed from the gut (63%) and widely distributed to body tissues and fluids including CSF.

Question 85

Penicillins reach high concentrations in which of the following?
Your answer was not correct

• 
  A Vitreous humour
  
• 
  B CSF with normal meninges
  
• 
  C Proximal tubular fluid in kidneys Correct Answer
  
• 
  D Breast milk Your Answer
  

Explanation

Question 86

Regarding erythromycin, which of the following statements is correct?

• 
  A It has a large cross-reactivity with the penicillins Your Answer
  
• 
  B It is bacteriostatic only
  
• 
  C It is inactivated by beta-lactamases
  
• 
  D It binds to the 50 s sub-unit of the bacterial ribosome Correct Answer
  

Explanation

Macrolides bind to the 50s subunit of the ribosome, they are both bactericidal and bacteriostatic. They inhibit the p450 system and thus increase the concentration of multiple drugs. Resistance to the macrolide is achieved by the reduction of the permeability of the bacterial cell wall, efflux pumps, production of esterases and modification of the ribosomal binding site. Macrolides are effective against both gram positive and negative bacterial

Question 87

Which of the following antibiotics does not exert its action by inhibiting cell wall synthesis?
Your answer was not correct

• 
  A Vancomycin Your Answer
  
• 
  B Erythromycin Correct Answer
  
• 
  C Ceftriaxone
  
• 
  D Imipenem
  

Explanation

Erythromycin prevents bacterial protein synthesis.

Question 88

Which class of antibiotics listed below does not possess a beta-lactam ring?
Your answer was not correct

• 
  A Monobactams
  
• 
  B Cephalosporins
  
• 
  C Fluoroquinolones Correct Answer
  
• 
  D Carbapenams Your Answer
  

Explanation

Fluroquinolones are synthetic fluorinated analogs of naladixic acid

Question 89

The cephalosporin with the highest activity against gram positive bacteria is?
Your answer was not correct

• 
  A Cefuroxime
  
• 
  B Cefaclor Your Answer
  
• 
  C Cefipime
  
• 
  D Cephalothin Correct Answer
  

Explanation

Cephalothin is a first generation cephalosporin

Question 90

Which of the following is a second generation cephalosporin?
Your answer was not correct

• 
  A Cephalothin
  
• 
  B Cefoxitin Correct Answer
  
• 
  C Ceftazidime Your Answer
  
• 
  D Cephalexin
  

Explanation

Other 2^nd generation: cefaclor, cefotetan, cefuroxime, cefprozil, cefmetazole, loracarbef and cefonicid

Question 91

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

• 
  A They are usually active against neisseria species Correct Answer
  
• 
  B They are bacteriostatic but not bactericidal Your Answer
  
• 
  C They bind at the 30 s ribosome sub-unit
  
• 
  D They enhance metabolism by cytochrome pathways
  

Explanation

Macrolides bind to the 50s subunit of the ribosome, they are both bactericidal and bacteriostatic. They inhibit the p450 system and thus increase the concentration of multiple drugs. Resistance to the macrolide is achieved by the reduction of the permeability of the bacterial cell wall, efflux pumps, production of esterases and modification of the ribosomal binding site. Macrolides are effective against both gram positive and negative bacterial

Question 92

Which of the following vaccines is a live virus vaccine?
Your answer was correct

• 
  A Typhoid
  
• 
  B HBV
  
• 
  C Rabies
  
• 
  D Measles Correct Answer
  

Explanation

Typhoid vaccine-live bacteria,

HBV-inactive viral antigen,

rabies-inactive virus

Question 93

A patient with impetigo would be most likely to respond to which of the following drugs?
Your answer was not correct

• 
  A Phenoxymethylpenicillin Your Answer
  
• 
  B Streptomycin
  
• 
  C Metronidazole
  
• 
  D Cephalexin Correct Answer
  

Explanation

Question 94

Regarding metronidazole, which of the following statements is correct?

• 
  A It increases the anticoagulant effects of warfarin Correct Answer
  
• 
  B It is highly protein bound
  
• 
  C It poorly penetrates the CSF Your Answer
  
• 
  D It has a low bioavailability
  

Explanation

Metronidazole is an antiprotozoal drug with antibacterial activity against anaerobes. It is the treatment of choice for trichomonas-2g stat. It is well absorbed after oral administration and has a bioavailability of over 90% and readily penetrates the CSF. It has a low protein binding(10-20%). It produces a disulfiram like effect- the inhibition of acetaldehyde dehydrogenase and the accumulation of acetaldehyde and an increased "hangover effect". It is reported to potentiate the anticoagulant effect of coumarin type anticoagulants.

Question 95

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

• 
  A Ceftazadime has activity against pseudomonas
  
• 
  B Cefaclor is a first generation cephalosporin Correct Answer
  
• 
  C Third generation cephalosporins have greater gram negative cover than first generation cephalosporins
  
• 
  D They are not as sensitive to beta-lactamase as penicillins
  

Explanation

Cefaclor is a second generation Cephalosporin.  Other 2^nd generation cephalosporins include: cefoxitin, cefotetan, cefuroxime, cefprozil, cefmetazole, loracarbef and cefonicid

Question 96

Regarding zidovudine (AZT), which of the following statements is correct?
Your answer was not correct

• 
  A It has a short half life Correct Answer
  
• 
  B It blocks thymidine kinase Your Answer
  
• 
  C It is not used to treat retroviruses
  
• 
  D It has a similar mechanism of action to amantadine
  

Explanation

AZT is used to treat retroviral infections. It has a half life of 1-3hrs. AZT inhibits reverse transcriptase of HIV1/HIV2. Amantadine blocks the M2 proton ion channel of the virus particle and inhibits uncoating of the viral RNA within infected host cells, thus preventing its replication. AZT is well absorbed from the gut (63%) and widely distributed to body tissues and fluids including CSF.

Question 97

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

• 
  A Liver toxicity is the most significant toxic side effect
  
• 
  B It can be given orally to treat systemic illness
  
• 
  C It can cause fever, headache and confusion Correct Answer
  
• 
  D Its dose needs to be reduced in renal impairment Your Answer
  

Explanation

Amphotericin is only given orally to treat a fungal infection in the gut. The immediate side effects seen are due to an infusion related toxicity which can be ameliorated by slowing down the infusion rate or decreasing the daily dose. Hepatic and renal impairment have little or no effect on drug concentrations. Renal damage is the most significant toxic reaction

Question 98

Sulphonamides are a structural analogues of which of the following?
Your answer was not correct

• 
  A PABA Correct Answer
  
• 
  B Dihydrofolate
  
• 
  C Tetrahydrofolate
  
• 
  D Folic acid Your Answer
  

Explanation

Sulphonamides: "Folate Antagonist", a DNA synthesis inhibitors. -Competitive inhibitor of Di-hyrdopteroate synthase -Structurally similar to PABA (Para-amino-benzoid acid), a precursor required by di-hydropteroate synthase for production of di-hydropteroic acid and subsequent folate synthesis. -A synergistic effect with Trimethoprim, another "Folate Antagonist" which inhibits Di-hydrofolate reductase.

Question 99

Dantrolene is used in malignant hyperthermia. Which of the following statements best describes it's mechanism of action?
Your answer was not correct

• 
  A It is a succinylcholine antagonist Your Answer
  
• 
  B It decreases calcium release from sarcoplasmatic reticulum Correct Answer
  
• 
  C It causes hypothermia through muscle relaxation
  
• 
  D It has an antipyretic through prostaglandin inhibition
  

Explanation

Dantrolene has a spasmolytic function outside the CNS. It reduces skeletal muscle strength by interfering with excitation–contraction coupling in the muscle fiber. Dantrolene interferes with the release of activator calcium via the sarcoplasmic reticulm calcium channel, possible by binding to the same receptor used by ryanodine. Malignant hyperthermia results in massive calcium release, massive muscle muscle contraction, hyperthermia and lactic acid production. Triggers are often general anaesthesia and neuromuscular blockers. Dantrolene is used to stem the calcium release

Question 100

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

• 
  A It is metabolised to lorazepam
  
• 
  B It is metabolised to oxazepam Correct Answer
  
• 
  C It has a half life of 4 hours Your Answer
  
• 
  D It should not be used in convulsions of unknown origin
  

Explanation

Diazepam has a half life of 20-40hrs. It is used for any seizure disorder.

Question 101

Regarding SSRI's, which of the following statements is correct?
Your answer was correct

• 
  A They are effective in obsessive compulsive disorder Correct Answer
  
• 
  B They have more pronounced side effects than TCA's
  
• 
  C They are the treatment of choice in bipolar disease
  
• 
  D They usually have short half-lives
  

Explanation

Question 102

Regarding pralidoxime, which of the following statements is correct?

• 
  A It regenerates acetylcholine
  
• 
  B It regenerates acetylcholine receptors
  
• 
  C It regenerates acetylcholinesterase Correct Answer
  
• 
  D It regenerates succinylcholine
  

Explanation

Pralidoxime is used to reactivate acetylcholinesterase inhibited by organophosphates. It is only effective if given before irreversible binding of the OP and the acetylcholinesterase has occurred. Re-establishment of enzymic function rapidly reverses the nicotinic and muscarininc effects of OP poisoning

Question 103

The treatment of glaucoma does not include which of the following drugs?
Your answer was correct

• 
  A Alpha blocker Correct Answer
  
• 
  B Beta blocker
  
• 
  C Carbonic anhydrase inhibitor
  
• 
  D Cholino-mimetic agents
  

Explanation

Question 104

Regarding stemetil, which of the following statements is correct?

• 
  A It can cause neuroleptic malignant syndrome Correct Answer
  
• 
  B It can cause malignant hyperthermia Your Answer
  
• 
  C It can cause serotonin syndrome
  
• 
  D It has anti-emetic effect through serotonin antagonism
  

Explanation

Stemetil is prochlorperazine: gives dopamine (D2) receptor blockade, especially dopaminergic receptors in CTZ (chemoreceptor trigger zone) of the medulla. Also has anticholinergic, alpha blocker and NA channel blocking effects. Indications: anti emetic, migraines, not for psychotic episodes. Side effects: muscarinic (anticholinergic) blockade : dry mouth,/urinary retention, constipation, loss of accommodation, flushed (remember :red as a beet, mad as a hatter, blind as a bat, dry as a crisp). Alpha blockade: orthostatic hypotension. Another life threatening side effect is :Neuroleptic malignant syndrome (A high fever, stiff muscles, confusion, irregular pulse or blood pressure, tachycardia, sweating, arrhythmias.

Question 105

Select the correct statement regarding L-Dopa.