MDS PREP
Which of the following antibiotics shows an incidence of approximately 8% cross-allergencity with penicillins?
1) Bacitracin
2) Erythromycin
3) Cephalexin
4) Vancomycin
Pharmacology Answer: 3
Cephalosporins can cause allergic reactions in people with penicillin allergy. The overall rate of allergy to cephalosporins in people with penicillin allergy is approximately 5 to 10%, although rates may be higher for certain people. Allergic reactions to cephalosporins can be severe and even lifethreatening;
it is generally recommended that those allergic to penicillin avoid cephalosporins all together.
Local anaesthetic used as an antiarrhythmic agent is:
1) Bupivacaine
2) Lignocaine
3) Cocaine
4) Chlorprocaine
Pharmacology Answer: 2
It is also used to treat ventricular tachycardia and to perform nerve blocks
Dosage Of Local Anesthesia:
1) Safety dose of 2% Lignocaine is 4.5mg/kg without a Vasoconstrictor
Without a Vasoconstrictor 300 mg (maximum dose)
2) Safety dose of 2% Lignocaine is 7mg/kg with a Vasoconstrictor
With a Vasoconstrictor – 500 mg (maximum dose)
3) As 1ml of 2% Lignocaine contains 20mg – Where the Maximum safety dose being 300 mg
So 15 ml of Drug can be given safely
4) 1:1,00,000 concentration means 1 part of Adrenaline is 1,00,000 parts of Solution
Safety Dose of Adrenaline for Dental Use in normal patients is 0.2 mg – which means 20 ml of LA can be given to normal patients containing Adrenaline
For cardiac Patients the safety dose of Adrenaline is 0.04mg – Which means 4ml of LA can be given to Patients with cardiac problems containing Adrenaline
5) If the concentration of LA is 1:50,000 – 10 ml of LA can be given safely
Drug class causing free water clearance:
a) Diuretic
b) Saluretic
c) Uricosuric
d) Aquaretic
Pharmacology Answer: 4
Vasopressin antagonists like tolvaptan are aquaretics
In Dicumarol poisoning which Vit K is used
1) Menadione
2) Menaqunone
3) Phytonadione
4) None of the above
Pharmacology Answer: 3
To reverse the effect of overdose of oral anticoagulants:
Phytonadione (K1) is the preparation of choice, because it acts most rapidly, dose depends on the severity of upoprothrombinemia & bleeding.
All of the following drugs cross the placenta except?
1) Phenytoin
2) Diazepam
3) Morphine
4) Heparin
Pharmacology Answer: 4
Heparin Heparin does not the cross the placenta.
Hence its safe for use in pregnant patients who need anticoagulation.
Nonselective beta blocker possessing quinidine-like membrane stabilizing effects.
1) pindolol
2) acebutolol
3) sotalol
4) esmolol
Pharmacology Answer: 1
Beta-blockers, such as propranolol, labetalol, and pindolol, can have membrane stabilizing effects (eg, quinidinelike effects, Vaughan-Williams class I antiarrhythmic effects). This property, usually not evident with therapeutic doses, may significantly contribute to toxicity by prolonging QRS duration and impairing cardiac conduction. Seizures are more commonly observed in the drugs with quinidinelike membrane stabilizing effects.
The neuromuscular blocker that does not need reversal of action by neostigmine at the end of the operation is :
1) d–Tubocurarine
2) Doxacurium
3) Pipecuronium
4) Mivacurium
Pharmacology Answer: 4
Long acting non-depolarizing (competitive) NM blocking agents require reversal with neostigmine.
Mivacurium is the shortest acting NDMR. It does not require reversal due to its short duration of action.
Mivacurium can be used in day care surgery.
Penicillins:
1) Are the antibiotic of choice for anaerobic infections
2) Are bacteriostatic
3) Are protagonistic to tetracycline
4) Interfere with bacterial cell wall synthesis
Pharmacology Answer: 4
The penicillins all act by interfering with bacterial cell wall synthesis, by inhibiting cross-linking of the mucopeptides in the cell wall and as such are bacteriocidal. Bacteria are attacked when cells are dividing and so in theory antibiotics that are bacteriostatic would decrease the efficacy of bacteriocidal drugs. However, this doesn’t often cause a problem but tetracycline and penicillin are antagonistic and should not be used at the same time. Metronidazole is the antibiotic of choice for anaerobic infections.