Medical Pharmacology

Medical Pharmacology

By Christine Ragudo

​EASY CATEGORY

Multiple Choice

Cholinomimetics are not used in

• Glaucoma

• Myasthenia gravis

• Postoperative atony

• Partial heart block

• ​Cholinergic drugs DECREASE the conduction from atrium to ventricle, thus should be avoided in partial heart block

​

• Cholinergic drugs (PILOCARPINE & PHYSOSTIGMINE) are used in angle closure glaucoma

• Neostigmine = Acetycholinesterase inhibitor and a cholinergic drug

  = used for the treatment of Myasthenia gravis

• Neostigmine = used for post-operative paralytic ileus and post-operative urinary retention

Multiple Choice

A patient presents to emergency with pinpoint pupil, salivation, lacrimation, tremors and red tears. Plasma cholinesterase level was 30% of normal. Most probable diagnosis is:

• Organophosphate poisoning

• Dhatura poisoning

• Opioid poisoning

• Pontine hemorrhage

• Described in the case are characteristic features of anti-cholinesterase (organophosphate and carbamate) poisoning.

• Features of Organophosphate poisoning:

  a) Muscarinic symptoms: pinpoint pupil, salivation, lacrimation, urination, defecation, GI distress, vomiting, bronchospasm, bradycardia

  b) Nicotinic symptoms: Fasciculations and fibrillations of muscle, tachycardia, tachypnea

  c) CNS symptoms: Tremors, giddiness, ataxia, coma

  d) Red tears: due to accumulation of PORPHYRIN in the lacrimal glands

Multiple Choice

Which of the following is True?

Which of the following is not true:

• If a drug is administered rectally, it follows 1st order kinetics

• If a drug is administered IM, it follows zero order kinetics

• If a drug is administered IV, it follows 1st order kinetics

• Bioavailability is lower after oral administration than IV administration

• The order of kinetics of drugs does not depend upon the route of administration. It always depends on the TYPE OF DRUGS

​

• The Biooavailability of IV injection is 100%, but frequently lower in oral ingestion.​

Multiple Choice

Regarding Termination of Drug Action:

Regarding termination of drug action

• Drugs must be excreted from the body to terminate its action

• Metabolism of drugs always abolishes their pharmacologic activity

• Hepatic metabolism and renal excretion are 2 most important mechanisms involved

• Distribution of drugs out of the blood stream terminates the drugs' effects

• ​Action of a drug can be terminated either by hepatic metabolism or by renal excretion.

  ​

• ​Most of the drugs are inactivated by metabolism. However, some drugs may be activated from inactive form (prodrugs) and produce active metabolites.

  ​

• Some drugs like DIGOXIN acts away from blood leaving the blood stream and enters the heart to produce its action.​

Multiple Choice

The process by which the amount of a drug in the body

decreases after administration but before entering the

systemic circulation is called:

• Excretion

• First pass effect

• First order elimination

• Metabolism

• ​REDUCTION in the amount of drug BEFORE it enters the systemic circulation is called first pass metabolism (also known as first pass effect)

​

• If the amount of drug DECREASES AFTER entry into the systemic circulation, it is called ELIMINATION

  ​

Multiple Choice

Metabolism of a drug primarily results in:

• Activation of the active drug

• Conversion of lipid soluble drugs to water soluble

  metabolites

• Conversion of lipid soluble drugs to water soluble

  metabolites

• Conversion of water soluble drug to lipid soluble

  metabolites

• After metabolism most of the drugs become inactive and are excreted through the kidney. Lipid soluble drugs will be reabsorbed whereas water soluble drugs are easily excreted. Thus, metabolism of drugs helps in the conversion of lipid soluble drugs to water soluble metabolites.

Multiple Choice

A new drug is found to be highly lipid soluble. It is metabolized at a slower rate of 10% per hour. On IV injection, it produces general anesthesia that lasts for 15 minutes only. This short duration of anesthesia is due to:

• Metabolism of the drug in the liver

• High plasma protein binding of the drug

• Excretion of drug by kidney

• Redistribution

• ​Highly lipid soluble drugs like thiopentone are quickly distributed to the tissue having high blood supply (like brain).

• ​If the target organ is also having high blood supply -> drug action with be very quick (this is the case with general anesthesia like Thiopentone)

• Movement of the drug OUTSIDE THE BRAIN results to TERMINATION of its action -> thus called, REDISTRIBUTION​

Multiple Choice

Loading dose of a drug primarily depends on:

• Volume of distribution

• Clearance

• Rate of administration

• Half life

• LOADING DOSE - is given to SATURATE the tissue stores, which is dependent on the VOLUME OF DISTRIBUTION

  • it is used for drugs having very long t1/2

• MAINTENANCE DOSE - depends on the CLEARANCE

• Volume of distribution and Clearance = primary pharmacokinetic parameters

Multiple Choice

With respect to clinical trials of new drugs, which of the following is most correct?

• Phase I involves the study of a small number of normal volunteers by highly trained clinical pharmacologists

• Phase II involves the use of the new drug in a large number of patients (1000-5000) who have the disease to be treated

• Phase III involves the determination of the drug’s therapeutic index by the cautious induction of toxicity

• Phase IV involves the detailed study of toxic effects that have been discovered in phase III.

• ​Phase 1 - carried out in HEALTHY VOLUNTEERS, while other phases are conducted in patients

• Phase 2 - smalle number of PATIENTS

• Phase 3 - multicentric trial re​quiring LARGE number of patients

• Phase 4 - post-marketing trial conducted for every drug. It is done to know the RARE ADVERSE EFFECTS​

Multiple Choice

There are some undesirable but unavoidable pharmacodynamic effects of a drug, which are known as:

• Toxic effects

•  Idiosyncrasy

• Side effects

• Intolerance

• Side effects are UNWANTED but UNAVOIDABLE pharmacodynamic effects that occur at therapeutic dose (less than toxic dose)

• Intolerance - appearance of characteristic toxic effects of a drug in an individual at therapeutic doses.

• Toxic Effects - result of EXCESS pharmacologic action of the drug due to OVERDOSE or PROLONGED use.

Multiple Choice

Diagnosis of Myasthenia gravis is done by using:

• Edrophonium

• Neostigmine

• Succinylcholine

• Atropine

• Myasthenia gravis can be differentiated from cholinergic crisis with the help of a short acting anticholinesterase agent, EDROPHONIUM

• It improves the symptoms in myasthenia gravis whereas worsens the condition in cases of cholinergic crisis.

• Neostigmine is used for the treatment of Myasthenia.​

Multiple Choice

A direct acting cholinomimetic that is lipid soluble and has been used in the treatment of glaucoma is:

• Acetylcholine

• Physostigmine

• Pilocarpine

• Neostigmine

• Pilocarpine is a DIRECTLY ACTING and Physostigmine is an INDIRECTLY ACTING cholinomimetic useful for glaucoma.​

Multiple Choice

You diagnose a patient with anticholinesterase poisoning presenting with profuse sweating, diarrhea and constricted pupils. You decide to administer him atropine. All of the following actions will be reversed by atropine, EXCEPT:

• Hypotension

• Central excitation

• Muscle paralysis

• Constriction of bronchioles

• Atropine is a non-selective ANTAGONIST at MUSCARINIC receptors.

• Atropine can penetrate blood-brain barrier and REVERSE MUSCARINIC ACTION in the CNS.

• Atropine can REVERSE hypertension and bronchoconstriction caused by stimulation of muscarinic receptors.

• Muscle paralysis is due to NICOTINIC (NN) action on which it has no activity​

Multiple Choice

Pin-point pupil suggests poisoning with:

• DDT

• Opiates

• Belladonna

• Barbiturates

• Causes of Pin-Point Pupils:

​

1. Opioids poisoning

2. Organophosphate poisoning

3. Carbamate poisoning

4. Carbolic acid poisoning

5. Pontine hemorrhage​

Multiple Choice

Which is TRUE about Dobutamine:

• Dobutamine decreases peripheral resistance

• Acts on D1 and D2 receptors

• Decrease kidney circulatione

• Has no effect on coronary circulation

• Dobutamine acts by activating B1 receptors and may DECREASE peripheral resistance (minor effect) on B2 receptors. It has NO effect on Dopamine D1 or D2 receptors.

• Dobutamine is a DIRECT-ACTING INOTROPIC agent whose primary activity results from stimulation of the B receptors of the heart, while producing mild chronotropic, hypertensive, arrhythmogenic and vasodilative effects.

• Dobutamine DOES NOT release enodgenous Norepinephrine unlike Dopamine.​

Multiple Choice

A child has swallowed 2 bottles of nasal decongestant whose primary ingredient is a-adrenoceptor agonist drug. The signs of alpha activation that may occur in this patient include:

• Tachycardia

• Dilatation of pupil

• Vasodilation

• All of the above

• Stimulation of a-receptors cause MYDRIASIS, whereas tachycardia and vasodilation are due to activation of B-adrenergic receptors.​

Multiple Choice

All are side effects of Salbutamol, EXCEPT:

• Palpitation

• Muscle tremors

• Sedation

• Throat irritation

• Side effects of Salbutamol:

​ a) Palpitation

b) Muscle tremors

c) Throat irritation

d) Nervousness

e) Ankle edema​

Multiple Choice

Which is not a 2nd generation anti-histaminic agent?

• Cetirizine

• Cyclizine

• Loratidine

• Fexofenadine

• Antihistaminics are classified into 1st generation and 2nd generation on the basis of CNS PENETRATION and ANTICHOLINERGIC properties.

• 1st generation Antihistaminics = penetrates Bl​ood-brain barrier and possess additional anticholinergic properties​ (lacking in 2nd generation)

• Cyclizine is a first ​generation

• Cetirizine, Loratadine, and Fexofenadine are 2nd generation drugs.​

Multiple Choice

Which of the following can reverse one or more smooth muscle effects of circulating histamine in humans?

• Granisetron

• Adrenaline

• Ranitidine

• Sumatriptan

• Adrenaline is physiological ANTAGONIST of Histamine.

• Adrenaline REVERSES bronchoconstriction caused by Histamine.

• Ranitidine is an H2 antagonist that DECREASES gastric acid secretion but has NO effect on smooth muscles.​

Multiple Choice

After taking a drug for migraine, the patient developed nausea and vomiting. He also developed numbness in the tip of the finger that turned to blue. Which drug caused the above findings?

• Dihydroergotamine

• Sumatriptan

• Aspirin

• Butorphanol

• This is a classical sign of ERGOT-INDUCED vasoconstriction.

• Dihydroergotamine can be used for acute attack of migraine and may result in symptoms presented in the case.

• Due to its vasoconstricting potential, ergot alkaloids are CONTRAINDICATED in patients with peripheral vascular disease, which may lead to development of gangrene.​

Multiple Choice

Aspirin should be used with caution in the following groups of patients because of which of the following reason:

• In diabetics, because it can cause hyperglycemia

• In children with viral disease, because of the risk of acute renal failure

• In gout, because it can increase serum uric acid

• In pregnancy, because of high risk of teratogenecity

• At Therapeutic Doses: Aspirin can cause HYPERURICEMIA, decreasing the excretion of uric acid, and should not be used in patients with gout. Aspirin can also decrease the uricosuric action of Probenicid.

• At High Doses (>5g/dl): it increases the excretion of uric acid, but cannot be tolerated.

• Aspirin is CONTRAINDICATED in <12yo due to risk of REYE'S SYNDROME (hepatic encephalopathy)

• Aspirin should be AVOIDED in diabetics due to risk of hypoglycemia. It should be avoided in pregnancy due to risk of LBW in babies, but does not cause congenital defects.​

Multiple Choice

Therapeutic uses of Prostaglandin E1 include all of the following, EXCEPT:

• Medical termination of pregnancy

• Impotence

• Primary pulmonary hypertension

• Maintenance of patent ductus arteriosus

• PGI2 analogs (Epoprostenol and Treprostinil) are used for treatment of pulmonary hypertension

• PGE1 analogs are used for medical abortion (Misoprostol), impotence (Alprostadil), and maintenance of the PDA (Alprostadil)​

Multiple Choice

Which of the following patient characteristics is a possible reason for the use of Celecoxib in the treatment of arthritis?

• History of severe rash after treatment with Sulfonamide antibiotic

• History of gout

• History of peptic ulcer disease

• History of Type 2 DM

• Non-selective COX inhibitors on long term use are associated with peptic ulcer disease. These should be avoided in the patients having history of PUD. Selective COX-2 inhibitors like Celecoxib are safe in this regard.

Multiple Choice

A newborn was diagnosed as having a congenital abnormality that resulted in transposition of great vessels. While preparing for surgery, the medical team needed to keep the ductus arteriosus open. They did this by infusing:

• Cortisol

• Indomethacin

• Alprostadil

• Tacrolimus

• Prostaglandins (like Alprostadil) are used to keep ductus arteriosus patent whereas Aspirin or Indomethacin are used for the treatment (closure) of PDA.

Multiple Choice

Which of the following statements is TRUE of Ketorolac?

• Has potent anti-inflammatory activity

• Its analgesic efficacy is equal to morphine in postoperative pain

• Is used as preanesthetic analgesic

• It interacts with opioid receptor

• Ketorolac is an NSAID promoted for systemic use mainly as an analgesic, not as an anti-inflammatory drug (though it has typical NSAID properties)

• Ketorolac has significant analgesic efficacy and has been used successfully to replace Morphine in situation involving mild to moderate postsurgical pain.​

Multiple Choice

Which of the following drugs is useful in acute attack of gout?

• Furosemide

• Sulfinpyrazone

• Allopurinol

• Piroxicam

• NSAIDS and Colchicine are HIGHLY EFFECTIVE in ACUTE GOUT

• Allopurinol and Sulfinpyrazone are​ highly effective in CHRONIC GOUT.

• Furosemide causes HYPERURICEMIA and should be avoided in patients with gout.​

• ​Cholestyramine = INHIBITS intestinal absorption of Digoxin

• Thiazides = result in HYPOKALEMIA and may precipitate Digitalis Toxicity by Pharmacodynamic interaction

• Quinidine and Verapamil = reduces the excretion of Digoxin and may precipitate toxicity (Pharmacokinetic interaction)​

Multiple Choice

Digoxin is NOT indicated in:

• Atrial flutter

• Atrial fibrillation

• High output failure

• PSVT

• Digitalis is an ionotropic agent that is indicated when heart is not able to pump the blood adequately.

• High output failure is seen in conditions like Anemia and Thyrotoxicosis where the heart is contracting vigorously.

• Cardiac glycosides are NOT INDICATED in high output failure.​

Multiple Choice

Which of the following drugs is beneficial in a refractory congestive heart failure by increasing cardiac conrtactility and decreasing preload and afterload?

• Amiloride

• Amiodarone

• Amrinone

• Carvedilol

• Amrinone is a phosphodiesterase inhibitor and acts as an INODILATOR.

• Amrinone has a positive inotropic effect (increase cardiac contractility) as well as vasodilator action (decreasing preload and afterload)

Multiple Choice

The antihypertensive which causes decreased libido and impotence is:

• Atenolol

• Enalapril

• Prazosin

• Diltiazem

• Diuretics have maximum risk of causing sexual dysfunction followed by beta blockers.

• Atenolol, Metoprolol, and Carvedilol have high risk whereas Nevibolol has minimum risk of erectile dysfunction.

• ACE inhibitors decrease the risk.​

Multiple Choice

All of the following are useful in the intravenous therapy for hypertensive emergencies, EXCEPT:

• Fenoldopam

• Urapidil

• Enalaprilat

• Nifedipine

• Nifedipine can be used rarely for the rapid control of blood pressure but the route of administration is SUBLINGUAL.

• Fenoldopam = is a D1 agonist used IV for hypertensive emergencies

• Urapidil is a blocker

• Enalaptilat (not enalalpril) can be used for the same indication​

Multiple Choice

Drugs that can be used for treatment of hypertension in a diabetic patient are the following, EXCEPT:

• Losartan

• Captopril

• Amlodipine

• Hydrochlorothiazide

• ACE inhibitors (Captopril) and AT 1 antagonists (Losartan) are first choice antihypertensive drugs for diabetic patients.

• Calcium channel blockers (Amlodipine) and a-blockers (Prazosin) are also safe for diabetics

• Thiazides and B-blockers should be AVOIDED in diabetes mellitus

Multiple Choice

All of the following antihypertensive drugs increase plasma renin activity, EXCEPT:

• Clonidine

• Hydralazine

• Nifedipine

• Captopril

• Plasma renin activity is increased by reflex increase in sympathetic discharge

• Clonidine DECREASES central sympathetic outflow -> DECREASE plasma renin activity

• Vasodilators and ACEI -> INCREASE plasma renin activity​