MDS PREP
Which of the following is the first drug to be prescribed in status asthmaticus?
1) Salbutamol
2) Humidified oxygen inhalation
3) Hydrocortisone hemisuccinate
4) Sodium bicarbonate infusion
Pharmacology Answer: 3
Status asthmaticus/Refractory asthma
Any patient of asthma is susceptible to develop acute severe asthma which may be life-threatening. Upper respiratory tract infection is the most common precipitant.
(i) Hydrocortisone hemisuccinate 100 mg (or equivalent dose of another glucocorticoid) i.v. stat, followed by 100-200 mg 4-8 hourly infusion; may take upto 6 hours to act.
(ii) Nebulized salbutamol (2.5-5 mg) + ipratropium bromide (0.5 mg) intermittent inhalations driven by O2 .
(iii) High flow humidified oxygen inhalation
(iv) Salbutamol/terbutaline 0.4 mg i.m./s.c. may be added since inhaled drug might not get to smaller bronchi owing to severe narrowing/plugging with secretions
(v) Intubation and mechanical ventilation if needed
(vi) intensive antibiotic therapy to be used for treating chest infection
(vii) Treat dehydration and acidosis with saline + sod. Bicarbonate/lactate infusion.
Which of the following drugs have a narrow therapeutic index?
1) Lithium
2) Diazepam
3) Penicillin
4) Desipramine
Pharmacology Answer: 1
Other drugs with narrow therapeutic index:
Digoxin Gentamicin Amphotericin B Levothyroxine Prazosin Theophylline Quinidine Warfarin Valproic acid
Which of the following antihypertensive drugs should not be used in a patient on Lithium in order to prevent Lithium Toxicity?
1) Clonidine
2) Beta blockers
3) Calcium Channel Blockers
4) Diuretics
Pharmacology Answer: 4
Diuretics increase sodium loss in urine and increase lithium retention. Hence they should not be used in patients on Lithium.
Developed hypo reactivity to a drug is
1) Detoxification
2) Antagonism
3) Tolerance
4) Desensitization
Pharmacology Answer: 3
Tolerance: The capacity to absorb a drug continuously or in large doses without adverse effect; diminution in the response to a drug after prolonged use.
Which receptors are implicated in anti emetic effects:
1) D2
2) V2
3) MU2
4) GABA
Pharmacology Answer: 2
CTZ rich in D2 and 5HT receptors
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 of choice for cholera prophylaxis
1) Chromphenicol
2) Procaine Penicillin
3) Doxycycline
4) Erythromycin
Pharmacology Answer: 3
Treatment with a single 200-mg dose of doxycycline has been recommended
As studies in volunteers demonstrated conclusively, the disease is an immunizing process. Patients who have recovered from cholera are solidly immune for at least 3 years
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.