Pharm Block 1

mozowaba's version from 2016-05-20 03:20

Week 1

Question Answer
Major factor that affect drug absorptionLipid solubility of the drug
Name the three factors affecting the Ionization 1) Nature of the drug: acid or a base 2) pH of the medium (Body compartment) 3) pKa of the drug
10 pH-pKa= { non ionized } / { ionized }Basic drug
10 pH-pKa= { ionized } / { non ionized }Acidic drug
One major disadvantage of taking a drug orally?Less Bioavailability, also Delayed effects, therefore not good for emergency. Gastric irritation
The ____route is used for many protein drugs because such drugs would be digested in the digestive tract if they were taken orallySubcutaneous
The intramuscular route is preferred to the subcutaneous route when____ of a drug product are needed. larger volumes
Best way to take Nitroglycerin—which is used to relieve anginaSublingual Route
Used to localize the effect of a drug in a particular tissue or organ by delaying their systemic distribution (diagnostic agents, anticancer drugs, etc.)Intra-arterial Route
Method Injecting drug into the space around the spinal cordIntrathecal
Total Extracellular Fluid14L
Total Plasma volume4 L
Total Interstitial fluid10 L
Total Intracellular fluid28 L
Total body water is42 L
Major Factor affecting drug distribution Plasma Protein binding
Acidic drugs mainly bind toAlbumin
Basic drugs mainly bind toAlpha1-acid-glycoprotein
Percentage of lithium that is bound to protiens0%
Percentage of warfarin that is bound to proteins99%
Drug that has the least affinity for plasma proteins. Therefore less plasma concentration but very high tissue concentration is seen.Chloroquine
Drug that displaces warfarin and produces bleeding, an adverse effect of warfarin.Sulfonamide
When an action on the CNS is required, drugs that do not cross the blood-brain barrier must be administered byIntrathecal injection (directly into the cerebrospinal fluid)
Formula for Volume of DistributionVd=D/C0
In few cases, the metabolite could be the active form of the original drug. Such drugs are called as Prodrugs. egPrednisone, Enalapril, Cyclophosphamide, Spiranolactone, (PECS)
Phase- I Biotransformation ReactionsNon Synthetic reactions
Phase-II Biotransformation ReactionsSSynthetic or Conjugation
Usually convert the Parent drug to more polar metabolite by introducing a functional group e.g. –OH, -SHPhase-1 reactions
Oxidation is the most common type of reactionPhase-1 reactions
Polar molecules that are readily excreted and often inactive.Conjugates (Phase-2 reactions)
Examples of what type of reactions Phase-2 reactionsAcetylation: INH, Hydralazine & Acetaminophen
Examples of what Phase-1 reactionsOxidation Reactions
The reactions are catalyzed by microsomal enzymes (mixed function oxidases or monooxygenases or Cytochrome P 450) and also by non microsomal enzymes (alcohol dehydrogenase, xanthine oxidase, etc.).Oxidation Reactions (Phase-1)
Drugs known to cause CYP 450 induction areRifampicin, Barbiturates, Phenytoin, Carbamazepine Glucocorticoids, and Alcohol chronic administration
_____ is induced by phenobarbitone, phenytoin and rifampin. Warfarin and phenytoin are common substrates.CYP 2C9
CYP 450 enzyme inhibitionCimetidine & Grape fruit juice
Non-microsomal enzymes can be ____but cannot be induced by drugs.Inhibited
Examples of drugs which undergoes acetylationHydralazine, Isoniazid & Procainamide
Functions to expel drugs/foreign substances from the intestinal mucosa into the lumen and thus enhance their excretionP-glycoprotein (P-gp)
Found in MDR (Multi Drug Resistant)-cancer cells. (Calcium Channel Blockers prevents P-gp and inhibits MDR)P-glycoprotein (P-gp)
Used to prevent the development of resistance in treatment of cancer and malariaVerapamil
This character of a drug results in Long plasma half life and prolonged effect of a drugDrugs that undergo Enterohepatic cycling or recirculation
Examples of drugs that undergo enterohepatic cyclingamphetamine, morphine, estradiol, oral contraceptive pills
Examples of P-gp inhibitorsVerapamil, Grapefruit juice
Acidification of urine is done by givingAmmonium chloride ( NH4Cl) or Vitamin C or Canberry juice
Alkalinization of urine done by givingSodium bicarbonate (NaHCO3) or Acetazolamide
Important among many drugs secreted in the tubulePenicillin, Probenecid, and Diuretics
Drug that Compete with the penicillin. Penicillin secretion from the renal tubules is reduced and penicillin stays for a long time in the body leading to prolonged action. Therefore ___ is combined with penicillin to increase penicillin's duration of actionProbenecid
Drug that competes with Uric acid for its reabsorption in renal tubule. Uric acid reabsorption is reduced and excreted in urine. This action of ____ is useful in the treatment of Gout.Probenecid

Qn. 10. Mention names of

Question Answer
2 Drugs eliminated by p-glycoproteinsDigoxin & Cyclosporin
2 Drugs which inhibits p-glycoproteinsVerapamil & grapefruit juice
2 Drugs which undergo acetylationINH & Hydralazine & Procainamide
3 drugs which induce hepatic enzymesRifampin, Barbiturates, Phenytoin, Glucocorticoids, Alcoholic Chronic Administration
3 drugs which inhibit hepatic enzymesCimetidine, SSRIs, Keotconazole, Macrolide Antibiotics & grapefruit juice