LATEST HIGH YIELD POINT FOR PHARMACOLOGY 2015
LATEST HIGH YIELD POINT FOR PHARMACOLOGY 2015
GENERAL PHARMACOLOGY
MC mode drug absorption is passive diffusion
– Vd(Volume of distribution) is hypothetical volume in which the drug is distributed
– Vd =amount/plasma concentration
Clarence is the volume of plasma that gets filtered of the drug in unit time
Clarence (CL) = Rate of elimination\Plasma concentration
It is of two types- Zero order (amount constant) & First order (fraction constant)
– Both half-life and CL remain constant in first order kinetics while both change in zero order
Half-life-Time taken by the drug to reduce its concentration by half.A drug is eliminated completely in 4-5 half lifes.
It can tell about total duration of drug action and time to achieve plasma steady state concentration
Dose response curve is the relationship between log of dose and response. Slope indicates safety, X-axis indicates potency and height indicates efficacy
AUTONOMIC NERVOUS SYSTEM
• Botulinum toxin reduces release of acetylcholine
• Acetylcholine is metabolised by true (neuronal enzyme) & false pseudocholinesterase
(deficiency causes apnea)
• Bethanechol (direct acting cholinomimetic) is used in Hirsprung’s disease, achalasia cardia and post-operative urinary retention
• Neostigmine is DOC for post operative recovery from non-depolarizing blockers, cobra bite and myasthenia gravis
• DOC for organophosphate poisoning is atropine; cholinesterase re-activators e.g. pralidoxime, obidoxime can be used
• Atropine is C.I. in amanita muscaria poisoning
• Glycopyrrolate is atropine substitute specially useful for older patients undergoing surgery as it is more cardiostable
• Pipenzolate is used for infantile colic ,while fleoxate is used for ureteric colic
• Hyosine butylbromide (Buscopan ) is used commonly as anticholinergic drug for abdominal pain of spasmodic type
• Dicyclomine has both antiemetics and anti-motion sickness property
• Hyoscine (levo-scopolamine) is DOC for motion sickness and has amnesic properties
(was used post world war-2 to peoduce amnesia)
• Adrenaline is DOC for angioedema ,anaphylactic shock ,cardiac arrest
• Isoproterenol is DOC for heart block (Causes pure rise of systolic BP)
• Mephenteramine is DOC for short term rise of BP
• Dopamine is DOC for cardiogenic shock; acts on D-1 receptors in kidney–> renal vasodilator
• Dobutamine (beta-1 agonist doesn’t* act on dopamine receptors) is DOC for pump
failure (e.g. following AMI, heart surgery)
• Phenyleprine is the drug that produces mydriasis without cycloplegia
• Midodrine is DOC for postural hypotension
• Methylphenidate is DOC for ADHD
• Imipramine is DOC for nocturnal enuresis due to its anticholinergic property
• Ephedrine is DOC for hypotension induced by spinal anesthesia
• Alpha-blockers are of two types (selective & non-selective)
• Prazocin, terazocin are selective alpha-1 blockers that do not cause reflex tachycardia as they don’t increase release of norepinephrine
• First dose hypotension is MC side effect of alpha bockers; they don’t increase lipid levels like beta-blockers-rather reduce them
CARDIOVASCULAR DRUGS
• Nitrates are the DOC of initial choice for all sorts of angina pain
• Nitrates act by delivering NO (nitric oxide) and are mainly venodilators
• Beta blockers are contraindicated in variant angina (would cause unopposed vasospasm)
• DOC for variant angina (also called Prinzmetal’s angina) are CCBs
• MC side effect of nitrates is headache or postural hypotension (tolerance develop with nitrates on regular use)
• DOC for hypertension with angina is beta-blocker(Beta-blockers are DOC for HT in stressed patients & those with high rennin levels)
• DOC for hypertension with diabetes/nephropathy or rennin hypertension is ACE inhibitors (MC side effect-cough ,also cause hyperkalemia,C/I in bilateral renal artery stenosis)
• ACE inhibitors are now initial DOC for CHF
• Procainamide is MC drug causing drug induced SLE (kidney is NOT involved)
• Amiadarone is the most efficacious,broadest spectrum & longest –acting (t ½ =70 days) anti-arrhythmic drug .Its most common side effect is pulmonary fibrosis –it also causes hypothyroidism & hyperthyroidism
• Bretylium is DOC for LA induced arrhythmias-acts by inhibiting release of norepinephrine
• Sotalol is beta-blocker with K+ channel blocking activity
• Adenosine is the shortest acting anti-arrhythmic drug (<10 seconds) and is DOC for paroxysmal supraventricular tachycardia
• Digoxin(t ½=24-36hrs) is MC used cardiac glycoside ,excreted unchanged from kidney.Therefore ,C/I in renal failure .Digitoxin(t ½=165 h) undergoes enetrohepatic circulation and is safe in renal failure (C/I in hepatic failure)
• Digoxin acts by inhibiting Na+K+ATPase and therefore increases cardiac contractility;
heart rate is NOT increased (rather decreased due to AV block)
• Digoxin is Cl in obstructive cardiomycopathy,aortic stenosis,ventricular tachycardia, and partial heart block (it is safe in full heart block)
• MC precipitating factor of digoxin toxicity is hypokalemia (hyperkalemia is protective)
• DOC for digoxin toxicity is potassium (C/I in overdose)
• DOC for overdose of digoxin toxicity is DIGIBIND (Fc fragment of digoxin binding antibody)
• Esmolol is shortest acting beta-blocker (t ½=<10 minutes) ; metabolized in plasma therefore is safe in renal /hepatic failure(atenolol is longest acting beta-blocker)
• Sincere MAN (Sotalol ,Metoprolol,Atenolol,Nadolol) are water soluble betablockers and are excreted unchanged (C/I in renal failure)