Pharm Gi Flashcards
Active comonent is 5- aminosalicylic acid . Thought to inhibit prostaglandin synthesis, block neutrophil migration.
Sulfasalazine and active metabolite mesalamine
Dicyclomine
Anti-spasmodic by blocking muscarinic receptors on enteric plexus and smooth muscle.
At high doses it will have anti- chollinergic side effects like dry mouth blurred vision
Not used freq
Side effects and administration of sulfasalazine and mesalamine respectfully
Side effects due to sulfa pyridine component - nausea GI upset arthralgias myalgias bone marrow suppression hypersentivitiy rxn
Mesalalamine can be administered as rectal suppository
Other drugs used
Azathioprine and 6- mercaptopurine - immunosuppressive drugs
Metronidazole
Methotrexate - crohns not uc
Anti TNF drugs
MOA of metronidazole a s tinidazole
The nitro gourd is reduced in anaerobic bacteria and protozoan
The reactive products are responsible for its anti microbial activity
Works against gut anaerobes and is cidal against obligate anaerobes
C. Diff, giardia lamblia, entamoeba histolytica
Metronidazole and tinidazole
Bacteriodes , fusobacterium , trichomonoas
Metronidazole and tinidazole
Moderately active against h. Pylori
Metronidazole and tinidazole
Side effects of metronidazole
Nausea, headache, anorexia,band metallic taste
Drug rxns with metro and tinidazole
Tin has fewer side effects
Abstain from etoh bc of disulfiram rxn - m-24hrs t-72 hr
Inhibit warfarin metabolism potentiating it’s effects
Met class b Tin class c for pregnancy
Salmonella , shigella , E. coli and campylobacter
Tmp/smx and fluoroquinolones
Severe campylobacter
Erythromycin
Amebic infections
Iodoquinol and metronidazole - iod remains in lumen and may cause diarrhea and rash
Ending - tidine
Histamine H2 receptor antagonist
Only h2 receptor antagonist that causes issues
Cimetidine - anti androgenic - causes gynecomastia
And potent p450 inhibitor
Ending - prazole
Proton pump inhibitors - omeprazole and lansoprazole an esomeprazole
Moa of proton pump inhibitors
Acid labile prodrugs administered in enteric coated tablets. The uncharged form enters the cytoplasm of the partial cell. In the acidic caniculus it’s converted to active sulfonamide form. Which forms a covalent disulfide link with cysteinyl residue in the proton pump on luminal side of parietal cell. This depends on the conformational change of the active H/K-ATPase pump. So it’s taken 30-60 min before meals. Irreversible and better than h2 blockers
Use of h2 antagonist
Dyspepsia - give 30 min befor meals
Peptic ulcer disease - at night on empty stomach - relapse need to treat h. Pylori
Gerd and lpr
Use of ppis
Peptic ulcer diseas - more effective ths. H2 blockers
NSAID associated ulcers , gerd, lpr, zollinger- Ellison syndrome
Adverse effects of PPIs
Lack of acidic environment in stomach will lead to poor absorption of some nutrients like calcium. And can increase c. Diff
Drug interactions of PPIs
Metabolized by CYP 450 . Pts with polymorphism in 2c19 will clear them more slowly.
Omeprazole can inhibit met of warfarin, diazepam, phenytoin, and carbamazepine
Adverse effects of Antacids - aluminum, magnesium hydroxides and calcium carbonate
Aluminum- constipation
Magnesium - diarrhea
So give together
Calcium- lead go greater absorption of sodium bicarbonate - transient metabolic alkalosis
Sucralfate
Sulfated polysaccharide that adheres to ulcer creators and epithelial cells, inhibit pepsin- catalyze hydrolysis of mucosal proteins and stim prostaglandin synthesis. This forms a protective barrier that allows the ulcer to heal.
PUD but elf effective than h blockers and PPIs
Inhibit absorption of digoxin
Bismuth sub salicylate
Anti secretory anti inflammatory and anti microbial effects
- pepto-bismol
- nausea and cramps relieved by thus
Dark stools and black tongue.
H. Pylori treatment
Combos
PPIs and amoxicillin and then switch to ppi clarithromycin and metronidazole
Entecavir
Nucleoside analogue used in primary treatment of hep b.
Inhibits all three functions of hbv polymerase.
Low drug resistance, excellent choice for patients not exposed to lamivudine but resistance mat develop in pts resistant to lamivudine
Tenofovir
Treat hbv low rate of resistance. Effective against lamivudine resistant hbv .
Possible renal impairment
Telbivudine
nucleoside analogue. Tx hbv . Dose resistance emerging
Interferon alpha or pegylated interferon
Treatment hbv - May be associated with severe flare up often precluded to HBeAg clearance but in pts with cirrhosis in pts it can lead to liver failure. Needs to be injected so limits it’s use
Adefovir
Nucleoside analogue - hbv
Not first line bc takes too long may cause Renal impairment, and resistance develops
Lamivudine
Nucleoside analogue . Hbv
Resistance is a problem. Can be used in pregnant pts
Side effects of nucleoside and tides
Headache, fatigue , nausea , lactic acidosis, hepatotoxicity
Treatment genotype 2 hep c
Pegylated interferon Alpha + ribavarin
Treatment genotype 1 hep c
Boceprevir or telaprevir in combo with pegylated interferon alpha and ribavirin. Inhibit replication of hcv in host cells by binding to NS3/4 protease of HCV
MOA of the bendazoles ( al, me, thia)
Bind beta tubulin and thereby inhibit the production of tubulin dimers which then impairs glucose uptake and depletes glycogen stores
Contra for pregnant ppl
Pyrantel
MOA: activated cholinergic nicotine receptors in nematode so causing a depolarization blockade
Alternative to bendazoles
Ivermectin
MOA : increase chloride permeability, which hyper polarizes the cell membrane resulting in paralysis of pharyngeal muscles
Use: scabies , pediculus humanus, strongyloiadiasis, ancylostoma braziliense, onchocerca volvulus
One dose a yr can prevent river blindness
Treatment of Cestodes and schistomiasis
Praziquantel
Praziquantel
MOA : outer surface of schistosomes is unique double membrane suture that protects it from host immune system. Praziquantel increases calcium per eabitiy in the tegumentnleading to its breakdown, allowing the host immune cells access to the worm antigens.
MOA methylphenidate
Dopamine uptake inhibitor ( dopamine motivation and reward)
ADHD
Side effects of methylphenidate
Anorexia , insomnia , nervousness, GI distress, irritability, tachy, dose depending motor and vocal tics
ADHD
Types of methylphenidate
Ritalin, methylin, concerta, the patch , dexamethypheindate
ADHD
Concerta
Triphasic release duration 10-12 hrs
ADHD
Dexamethypheindate
Can be sprinkled duration 12 hrs ADHD
MOA amphetamines
Enhances release and blocks reuptake of dopamine and ne. ( ne alert, attending, orienting)
ADHD
Adverse effects amphetamine / contraindications
Anxiety, motor tics, MAOI , cardiac abnormalities, hs drug abuse , seizure disorders glaucoma
ADHD
Types of amphetamines
Dextroamphetamine
Mixed amphetamine salts ( adderall)
Lisdexamfetamine
ADHD
Adderall
Cardiac abnormalities contraindicated
ADHD
Lisdexamfetamine
Amphetamine prodrug. Activated in the gut less potential for abuse
ADHD
Atomoxetine
ADHD
Norepi reuptake inhibitor
Ae- nausea, anorexia,increase pulse/ BP, constipation hepatotoxic
May take 1-2 weeks to work
Bupropion
ADHD
Dopamine and ne reuptake inhibitor
Ae: bulimia/ anorexia, seizure disorder, he substance abuse, head trauma
Improvement hyperactivity, hospitality and sleep
Clonidine
Central alpha 2 adrenergic agonist ( post synaptic for ADHD )
Sedation big side effect , orthostatic hypotension, dry mouth
More Effective for impulsivity and hyperactivity than in attentiveness. No worsen tics.
Guanfacine
Central alpha 2 Adrenergic agonist ( post synaptic for ADHD)
Sedation ( less than clonidine) orthostatic hypotension, dry mouth
More Effective for impulsivity and hyperactivity than in attentiveness. No worsen tics.
