PHARM block 3 without coagulation drugs Flashcards
GI drugs uses
most common forms of: nausea/vomiting, diarrhea, constipation, gerd
drugs used to induce therapeutic emesis
ipecacuana; hypertonic saline; apomorphine
ipecacuana
ipecac syrup; obsolete
use of drugs to induce emesis
to empty stomach after poison ingestion; alternative to/combo with gastric lavage
contraindications of drug-induced emesis
ingestion of corrosives (cleaning fluids); ingest aliphatics (petroleum -> lipid pneumonia); somnolence, unconciousness
adverse effects of drug-induced emesis
aspiration, vagal syncope, hypochloremia, hypovolemia, absorption of emetic drug (NaCl, ipecac)
antiemetic drugs
antihistamines (inhibit dopamine); phenothiazines; dopamine antagonists; 5-HT-antagonists; corticosteroids; cannabinoids (effective, illegal in some states); neurokinin-1-receptor antagonist; adjunct medications
antiemetic antihistamines
diphenhydramine, hydroxizine
diphenhydramine, hydroxizine adverse effects
sedation
diphenhydramine, hydroxizine indications
pregnancy, motion sickness
phenothiazines
perchlorphenazine, proemthazine
perchlorphenazine, proemthazine adverse effects
epm disturbances, dyskinesias, sedation
perchlorphenazine, proemthazine indications
metabolic/endocrine, cns
dopamine antagonists
metoclopramide, (domperidon) - risk of arrhythmia -> used in compounds
metoclopramide, (domperidon) adverse effects
s.a., but less pronounced
metoclopramide indications
widely used to prevent/treat moderate nausea/emesis
5-HT-antagonists
ondansetron, granisetron, tropisetron, dolasetron
ondansetron, granisetron, tropisetron, dolasetron adverse effects
CONSTIPATION (contraindicated w/opiates), headache
ondansetron, granisetron, tropisetron, dolasetron indications
cytostatic-induced EARLY vomiting
antiemetic corticosteroids
dexamethasone
dexamethasone adverse effects
none
dexamethasone indications
intracranial pressure, cytostatic-induced LATE vomiting; given together w/5-HT-antagonists
cannabinoids
marijuana, THC (dronabinol), nabilone
marijuana, THC, nabilone adverse effects
drowsiness, confusion, amotivational syndrome (prolonged use)
cannabinoids indications
wasting related to AIDS, cancer
neurokinin-1-receptor antagonist
aprepitant
aprepitant adverse effects
fatigue, dizziness, diarrhea
aprepitant indications
cytostatic-induced; combo tx
adjunct antiemetic drugs
benzodiazepines, atropine, scopolamine, erythromycin (prokinetic)
benzodiazepines antiemetic indications
anticipatory vomiting
erythromycin moa
macrolide antibiotic, motilin agonist
erythromycin uses
diabetic gastroparesis, postoperative GI atony -> prokinetic
metoclopramide moa
central D2 antagonist (dopamine); peripheral M1 agonist
metoclopramide uses
antiemetic, gerd, diabetic gastroparesis -> prokinetic
metoclopramide pk
oral, im, iv, rectal
metoclopramide pd
antiemetic; prokinetic (GI)
metoclopramide adverse effects
extrapyramidal symptoms, esp in children; restlessness; drowsiness; with prolonged, high dose -> galactorrhea, gynaecomastia, parkinsonoid
most important therapy for diarrhea
drinking balanced fluid to maintain kidney fxn
diarrhea-causing drugs
adrenergic blockers ((reserpine)); antimicrobials (tetracyclines, sulfonamides, broad spectrum) - affect flora; bile acids, fatty acids, carcinoid tumor secretions; digestive enzyme blockers (acarbose, orlistat); dietary agents (OLESTRA, some sweeteners); cardiac glycosides - sign of overdose; cholinergic agonists; laxatives; prostaglandins
drugs for diarrhea treatment
peripheral opioid-receptor agonists (loperamide, diphenoxylate (combine w/atropine)); tinctura opii; somatostatin; alpha2 agonists (clonidine); adjunct meds - spasmolytic drugs; bile-acid induced diarrhea (colestyramine); clostridium-difficile associated enterocolitis (vancomycin; metronidazole)
loperamide moa
mainly peripheral; opioid receptor agonist; OTC drug
loperamide pk
oral
loperamide pd
inhibits intestinal fluid secretion; inc intestinal fluid absorption; inc tonic (non-propulsive) intestinal smooth muscle tone
loperamide adverse effects
constipation; kids, high dose - opioid-like adverse effects
loperamide contraindications
ileus, subileus, fever, antibiotics-associated diarrhea, megacolon, pregnancy, lactation
ineffective drugs used for diarrhea
activated charcoal tablets; pektin; kaolin -> placebo, irritable bowel syndrome, ‘stool freaks’; drugs w/serious adverse effects -> antibiotics/septics in OTC preps, tannin
constipation-causing drugs
ALL opioids - strong; anticholinergics (antidepressants, phenothiazines, antiparkinson drugs); ganglionic blockers; calcium channel antagonists; k-wasting diuretics; ‘irritant’-type laxatives (chronic abuse)
types of laxatives
bulk-forming agents (fiber) - bran, psyllium, methylcellulose -> distend bowel -> inc peristalsis; hyperosmolar agents - sorbitol, lactulose, polyethylenglycol (for surgery prep) -> retain water in gut; stool softening/lubricating agents - docusate sodium, glycerin, mineral oil (can cause lipid pneumonia); stimulants/irritants - bisacodyl, castor oil, phenolphtalein, anthrachinones; enema - containing any of others (helps pregnant women push)
peptic ulcer drugs
proton pump inhibitors; H2-antagonists; antimicrobial agents; antacids; others - (anticholinergics), prostaglandins, mucosal protective agents (rare)
H2 receptor antagonists
cimetidine, ranitidine, famotidine, nizatidine
cimetidine characteristics
prototype drug; many pk interactions (cyt p450 inhibition - warfarin, phenytoin, theophylline); antiandrogenic effects; GYNAECOMASTIA
ranitidine characteristics
more POTENT; longer duration; no antiandrogenic effects; no gynaecomastia
famotidine + nizatidine characteristics
further improved potency, duration; nizatidine - 100% bioavail
cimetidine, ranitidine, famotidine, nizatidine pk
oral, IV
cimetidine, ranitidine, famotidine, nizatidine adverse effects
mild; headache, diarrhea, muscular pain, confusion
proton pump inhibitors (PPI)
omeprazole, lansoprazole, pantoprazole
omeprazole, lansoprazole, pantoprazole pk
oral, iv, prodrugs -> activated after secretion from gastric mucosal cells into acid canaliculi
omeprazole, lansoprazole, pantoprazole pd
IRREVERSIBLE! binding of proton pump; dose-dependent, complete inhibition of basal and stimulated acid secretion; long duration (up to 3d)
omeprazole, lansoprazole, pantoprazole adverse effects
mostly secondary to anacidity (gastric bacterial flora, aspiration pneumonia w/assisted resp)
antacids characteristics
weak base + HCL = salt + water; immediate relief from hyperacidity
antacids categories
absorbable/poorly absorbable - best in combos; laxative/constipative
antacids pd
SHORT duration (~2h); need large qty’s - not suitable for ulcers; repeat at short intervals for lasting effect
antacids adverse effects
alkalosis (absorble antacids); interference w/absorption of other drugs (chelation, adsorption)
typical poorly-absorbable antacid combinations
aluminumhydroxide (promotes constipation); magnesiumhydroxide (promotes laxation)
simethicone
de-foaming agent; takes off surface tension -> defoam -> dec bloating
misoprostol moa
stable analogue of prostaglandin E1
misoprostol pd
cytoprotective; only clinically effective in doses that also inhibit acid secretion
misoprostol uses
prevention of ulcers induced by NSAIDs - protects mostly the stomach
misoprostol adverse effects
not well tolerated; all ae’s associated w/PGs seen - nausea, diarrhea, abdominal cramps, uterine contractions
misoprostol contraindications
PREGNANCY
sucralfate characteristics
coating agent; complex of aluminumhydroxide, sulfated sucrose
sucralfate pk
topical action; little systemic absorption
sucralfate pd
coats ulcer ground in acidic environment; stimulates PG synth; ineffective when combo w/antacids
sucralfate uses
longterm maintenance therapy to prevent ulcer recurrence
therapeutic issues: peptic ulcer disease
all tx include PPI or H2-antagonist and 2 or 3 antimicrobial agents; antimicrobials prevent recurrence (no healing); HP eradication mostly successful; antimicrobials ~10d, PPI ~6wks; symptom relief best w/PPI; healing rate same for PPI/H2-ant; no diet recs; smoking stops healing, promotes recurrence
aspirin clinical effects
anti-inflammatory (directly in tissue); analgesic (2ndary to anti-inflammatory); antipyretic (only if temp is inc); anti-platelet (slightly inhibit thromboxane)
anti-inflammatory effects of aspirin
non-selective COX inhibition - irreversible acetylation (unique), salicylate-induced reversible inhibition (like NSAIDs); interference w/kallikrein/bradykinin system (minor) - interfere w/granulocyte adherence, PMN leukos, macrophages
analgesic effects of aspirin
mild/moderate pain; site of pain - peripheral; 2ndary to anti-inflammation; minor 2ndary cns effect at subcortical sites; co-medication in moderate/severe pain
antipyretic effects of aspirin
dec high temp, normal temp unaffected; regulation at cns level (cox inhibition, IL-1 formation); vasodilation; profuse sweating
anti-platelet effects of aspirin
irreversible acetylation of thromboxane synthetase - low dose effect, specific for aspirin, pre-systemic effect on thrombosis in portal vein, 8-10d effect, effects add up, stop after surgery; inhibit thromboxane synthetase by salicylate - high dose effect, mild
aspirin combined effect on coagulation
irreversibly inhibits TXA2 for life of platelet -> inc BT; inhibits COX in endothelial cells, but can synth new COX
aspirin adverse effects
analgesic, short-term doses - upset GI, slight inc BT; prolonged tx - erosive gastritis, gastric/duodenal ulcers/complications -> MUST have protection; high dose (unusual) - cns syndrome - salicylism (vomiting, tinnitus, vertigo); low dose - inc urate levels -> gout -> inc dose -> dec gout; impaired renal fxn when combo w/2d nsaid; aspirin-asthma; reye syndrome -> NEVER give to kids w/fever/viral infection
aspirin intoxication
respiratory alkalosis, then metabolic acidosis, mixed imbalances of acid-base homeostasis
aspirin adverse effects on kidneys
dec renal blood flow; acute interstitial nephritis; analgesic nephropathy
aspirin adverse effects on kidney: dec renal blood flow
pt’s w/compromised renal perfusion -> kidney synth PGE2, PGI2 (vasodilators) to balance vasoconstriction; aspirin dec PGs -> dec PGE2 -> inc na/h2o & dec PGI2 -> hyperkalemia, acute renal failure
aspirin adverse effects on kidneys: acute interstitial nephritis
type I hypersensitivity -> acute renal failure; almost any drug can cause interstitial nephritis, most common -> antibiotics/nsaids
aspirin adverse effects on kidneys: analgesic nephropathy
chronic interstitial nephritis from prolonged analgesics use, esp combos of diff agents; renal papillary necrosis after yrs -> chronic interstitial nephritis -> progressive chronic renal failure
aspirin clinical uses: antiplatelet dose level
prevent coronary events, transient ischaemic attacks; reduce colon ca incidence
aspirin clinical uses: analgesic dose level
tx mild/moderate pain; fever (not kids); moderate pain when combo w/codein; adjunct tx of severe pain w/strong opioids
ibuprofen characteristics
commonly used minor analgesic, otc
ibuprofen pk
oral, 99% protein bound
ibuprofen pd
nsaid
ibuprofen adverse effects
GI (less than aspirin); RARE: rash, pruritius, aseptic meningitis, tinnitus, dizziness, headache, fluid retention, acute renal failure, interstitial nephritis, nephrotic syndrome, hepatitis
diclofenac moa
potent COX inhibitor, some selectivity for COX-2
diclofenac pk
t1/2~1h; accums in synovial fluid (t1/2~6h); enteric-coated, sustained release available - important for chronic joint pain
diclofenac uses
analgesic (in combo w/codeine); antirheumatic
diclofenac adverse effects
like other nsaids
indomethacin characteristics
the more potent -> more efficacious -> more side effects
indomethacin moa
more potent, unselective COX inhibitor; additional anti-inflammatory effects