Term
| virus specific drug tx is available for which acute hepatitis infections? |
|
Definition
| just HCV! A B D and E mostly centered around PREVENTION. |
|
|
Term
| HAV vaccine - how long is it effective and how many doses (when)? |
|
Definition
| lasts 20 years, give one shot (abs develop within 2-3 weeks) then booster 6-12 months later |
|
|
Term
| HAV vaccine made from what? |
|
Definition
|
|
Term
| HBV vaccine made from what? |
|
Definition
|
|
Term
| what is the dosing for the HBV vaccine? |
|
Definition
| 3 IM injections - 0, 1, 6 months. (10-20mg for adults, double that for immunosuppressed, 5-10 for children less than 10) |
|
|
Term
| when are boosters recommended for HBV? |
|
Definition
| not recommended (invoke secondary IR). give to immunosuppressed pts and previously-vaccinated people who are exposed and who have circulating serum anti-HBs less than 10 mIU/mL |
|
|
Term
| why isn't a HCV vaccine available? |
|
Definition
| diversity of genotype makes it hard to make one |
|
|
Term
| what is the tx for acute HCV? |
|
Definition
| interferon alfa-2b. if not resolved in 3 mos give interferon alfa-2b + ribavirin (98% clearance) |
|
|
Term
| what is considered a "cure" in HCV? |
|
Definition
| viral RNA load suppression > 24 weeks |
|
|
Term
| what are the 5 drugs used to tx chronic HBV? |
|
Definition
| lamivudine, adefovir, entecavir, telbivudine, interferon alfa-2b |
|
|
Term
| what are the 5 drugs used to tx chronic HCV? |
|
Definition
| interferon alfa-2a, interferon alfa-2b, interferon alfacon-1, pegylated interferon alfa 2a, pegylated interferon alfa 2b |
|
|
Term
| lamivudine mode of action |
|
Definition
| (for chronic HBV) nucleoside analog (nucleoside reverse transcriptase inhibitor) --> phosphorylated by cellular kinases to active triphosphate form. competitively inhibits HBV reverse transcriptase and HBV DNA polymerase by competing with deoxycytidine triphosphate for incorporation into the viral DNA. chain termination after incorporation into viral DNA |
|
|
Term
| which 2 drugs for hepatitis are also used to tx HIV |
|
Definition
| lamivudine (originally for HIV, but longer half-life in HBV --> lower doses, fewer AE and increased safety); adefovir (aka tenovir) less toxic (lower) dose needed for HBV |
|
|
Term
| side effects/downside to lamivudine? |
|
Definition
| after rx, hbv returns and also drug resistance d/t mutations. after 1 year, 20% resistant. after 3 years, 50% resistant. few physical side effects: HA, insomnia, fatigue, gi discomfort |
|
|
Term
|
Definition
| nucleotide analog to adenosine monophosphate --> phosphorylated by cellular kinases to active diphosphate form. used against lamivudine resistant viruses. competitively inhibits HBV DNA polymerase -> chain termination after incorporation into viral DNA |
|
|
Term
|
Definition
| no significant drug resistance after 1 year (~4% after 3 yrs), hbv can reappear if tx stopped. physical side effects ~2% of patients, mild HA diarrhea GI discomfort |
|
|
Term
|
Definition
| nucleoside analog to guanosine, more effective than lamivudine or adefovir (greater viral suppression, normalization of lfts, histo improvement). competitively inhibits hbv dna pol (blocks all 3 functions - base priming, reverse transcription and synthesis of positive strand) |
|
|
Term
| side effects of entecavir |
|
Definition
| no significant resistance; has not been proven safe for preg women; few adverse effects, HA fatigue GI discomfort |
|
|
Term
| how does telbivudine work? |
|
Definition
| nucleoside analog, phosphorylated by cellular kinases to active triphosphate form, may lead to greater hbv viral load reduction than lamivudine. competitively inhibits hbv dna pol and causes chain term when incorporated into viral dna |
|
|
Term
| side effects of telbivudine |
|
Definition
| lower incidence of resistance than lamivudine. few, mild sx: HA, insomnia, fatigue, GI discomfort. POTENTIAL ASSOC WITH peripheral neuropathy, myopathies, myalgias |
|
|
Term
| how do interferon alfas work? |
|
Definition
| they are cytokines that exert antiviral immunomodulatory and antiproliferative effects. syntheiszed by host cells and cause biochemical changes leading to an antiviral state in cells. bind to specific membrane receptors on the cell surface and initiate a series of intracellular events including enzyme induction, suppression of cell proliferation, immunomodulatory events, and inhibition of viral replication |
|
|
Term
| what factors make a person more responsive to interferon alfa tx for chronic HCV? |
|
Definition
| HCV genotype 2 or 3; absence of cirrhosis on liver bx; low pre-tx HCV RNA levels |
|
|
Term
| interferon alfacon 1 used for tx of? |
|
Definition
|
|
Term
| interferon alfa 2a used for |
|
Definition
|
|
Term
| interferon alfa 2b used for |
|
Definition
| acute hcv, chronic hcv, chronic hbv |
|
|
Term
| what does pegylating the interferons do? |
|
Definition
| (polyethylene glycol covalently bonded) extends half-life and slows clearance of the agents --> less frequent dosing |
|
|
Term
| what is the dosing for lamivudine, adefovir, entecavir, telbivudine? |
|
Definition
|
|
Term
| how are interferons adminstered? |
|
Definition
| 2a and 2b subcutaneous or IM; alfacon-1 and peg 2a peg2b --> subcutaneous (injections once a week) |
|
|
Term
| side effects of interferon alfas? |
|
Definition
| flu like sx within 6 hrs of dosing (>30% pts) usually resolves with continued administration; nausea, fatigue, HA, arthralgia, rash, alopecia, anorexia, hypotension, edema. thrombocytopenia, granulocytopenia, elevated LFTs, NEUROPSYCH effects (severe), ABORTIFACIENT |
|
|
Term
| what are the contraindications for use of interferon alfas? |
|
Definition
| psychosis, severe depression, neutropenia, thrombocytopenia, symptomatic heart disease, decompensated cirrhosis, uncontrolled seizures, hx of organ transplant (other than liver), pregnancy |
|
|
Term
|
Definition
| guanosine analog phosphorylated intracellularly by host enzymes. not fully clear, appears to interfere with synthesis of GTP to inhibit capping of viral mRNA and inhibit RNA-dependent RNA pol of certain viruses. inhibits replication of a wide range of DNA and RNA viruses |
|
|
Term
| side effects of ribavirin |
|
Definition
| hemolytic anemia (10-20%); depression, fatigue, irritability, rash, cough, insomnia, nausea, pruritis. |
|
|
Term
| contraindications in ribavirin use |
|
Definition
| anemia, end-stage renal failure, severe heart disease, pregnancy |
|
|
Term
| what do 5-aminosalicylates treat and how do they work? |
|
Definition
| mild to moderate IBD. 5-ASA modulates inflammatory mediators derived from both cyclooxygenase and lipoxygenase pathways, may also interfere with production of inflammatory cytokines since 5-ASA inhibits nf-kB (transcription factor for pro-inflam cytokines). all work topically, no systemic inhibition of cyclooxygenase pathways, which would exacerbate sx) |
|
|
Term
| azo compounds include which 3 specific drugs |
|
Definition
| sulfasalazine, balsalazide, osalazine |
|
|
Term
| how do azo compounds work? |
|
Definition
| 5-ASA bound by an azo molecule (N=N) to an inert molecule or to another 5-ASA molecule. azo structure markedly reduces absorption of the parent drug from the small intestine. azo bond is cleaved by intestinal bacteria in the terminal ileum and colon releasing the active 5-ASA --> therefore high concentrations 5-ASA delivered to terminal ileum and colon |
|
|
Term
| what 2 specific drugs are mesalamine compounds? |
|
Definition
|
|
Term
|
Definition
| contains time release microgranules that release 5-ASA throughout the small intestine |
|
|
Term
|
Definition
| 5-ASA packaged with pH-sensitive coating that dissolves at pH7 (pH of distal ileum and proximal colon) |
|
|
Term
| what are the side effects of 5-ASA drugs? |
|
Definition
| mostly well tolerated. any AE mostly due to sulfasalazine (not bc of the 5-ASA part, but bc of the sulfapyridine molecule). nausea, gi upset, arthralgia, myalgia, bone marrow suppression, malaise, hypersensitivity to sulfa --> fever, exfoliating dermatitis, pancreatitis, hepatitis, pericarditis, pneumonitis, hemolytic anemia; sulfasalazine also impairs folate absorption (give dietary supp of folate). up to 40% patients cannot tolerate AE of sulfasalazine |
|
|
Term
| what do we use glucocorticoids for in GI? |
|
Definition
| tx of moderate to severe IBD. not useful for disease remission (d/t side effects of long term use) use to kick patient into remission but cannot be used to maintain it so taper dosage |
|
|
Term
| what are how are prednisone/prednisolone administered and whats the dosage? |
|
Definition
| most commonly used oral glucocorticoid, can be given via iV in severely ill pts. immediate duration of biological activity allows for once-daily dosing. tx with initial oral dose of 40-60 mg/d --> pt responds in 1-2 weeks --> dose tapered to limit side effects |
|
|
Term
| what do we use hydrocortisone for? and how is it administered |
|
Definition
| for tx of IBD involving RECTUM or SIGMOID colon. administered as enemas, foam, or suppositories to maximize colonic tissue effects and minimize absorption with topical tx (15-20% still absorbed) |
|
|
Term
| what do we use budesonide for? and how is it administered? |
|
Definition
| synthetic analog of prednisolone, used for tx of mild to moderate crohn's involving ileum and proximal colon. given orally (subject of first-pass metabolism, low oral bioavailability) slightly less effective than prednisolone but with significantly less adverse systemic effects |
|
|
Term
| what do we use to achieve remission in IBD? |
|
Definition
| purine analogs - azathioprine and 6-mercaptopurine |
|
|
Term
| what are purine analogs (azathioprine and 6-mercaptopurine) used for? |
|
Definition
| remission of IBD; reduce/eliminate steroids in patients who depend on long-term glucocoritcoid rx to control active disease |
|
|
Term
| how do purine analogs work? |
|
Definition
| unknown.6-thioguanine causes inhibition of purine nucleotide metabolism and DNA synthesis and repair --> inhibition of cell proliferation |
|
|
Term
| what is the halflife of purine analogs? |
|
Definition
| less than 2 hrs but active metabolites (6 thioguanine nucleotides) are concentrated in cells --> prolonged half-life of days. |
|
|
Term
| side effects of purine analogs? |
|
Definition
| dose related. nausea, vomiting, bone marrow depression (immunosuppressive), hepatic toxicity (reversible with dose reduction). routine lab monitoring of blood count and LFTs required. hypersensitivity in 5% (rash, fever, diarrhea, pancreatitis, hep) |
|
|
Term
| what are the drug interactions of purine analogs? |
|
Definition
| allopurinol reduces metabolism of purine analogs; dose of purine analogs should be halved in pts takng allopurinol |
|
|
Term
| what is methotrexate used for and how is it administered? |
|
Definition
| antimetabolite used to achieve remission of crohn's disease. administered orally, subcutaneously, IM |
|
|
Term
| how does methotrexate work? |
|
Definition
| inhibition of dihydrofolate reductase. shares structural homology with interleukin-1, may interfere with its inflammatory actions and may stimulate release of adenosine, an endogenous anti-inflammatory autacoid. may stimulate apoptosis and death of activated t-lys |
|
|
Term
| side effects of methotrexate |
|
Definition
| only with high doses (not usually seen at the doses used for IBD) bone marrow depression, megaloblastic anemia, alopecia mucositis. folate supplementation to reduce occurance of side effects |
|
|
Term
| how does anti-tnf therapy help in IBD patients? |
|
Definition
| dysregulation of the TH1 T cell response is present in IBD (esp crohns) and tnf-alpha is one of the key pro-inflammatory cytokines. so regulating tnf-alpha wil help decrease the inflammatory response |
|
|
Term
| what is infliximab? how is it administered and what is it used for? |
|
Definition
| chimeric human-mouse monoclonal antibody to TNF-alpha. administered IV (half life 8-10 days, 2 weeks for clinical response). used in moderately severe and fistulating crohns disease (symptomatic improvement in 66% of patients and disease remission in 33%) |
|
|
Term
|
Definition
| binds soluble TNF-alpha --> prevents cytokine from binding to its receptors. also binds to membrane-bound TNF-alpha and neutralizes its activity. promotes complement activation and antibody-mediated cellular cytotoxicity of inflammatory cells |
|
|
Term
| side effects of infliximab? |
|
Definition
| infection d/t suppression of TH1 inflammatory response (pneumonia, sepsis); reactivation of latent tuberculosis (all pts must undergo purified protein derivative testing prior to tx. those with + test results must receive prophylactic therapy for tuberculosis) |
|
|
Term
| what is adalimumab and how is it administered? |
|
Definition
| fully human monoclonal antibody to human TNF-alpha (100% human); administered subcutaneously, halflife 2 weeks |
|
|
Term
| what is certolizumab and how is it administered |
|
Definition
| chimeric mouse-human monoclonal ab to human TNF-alpha (75% human). given subcutaneously halflife 2 weeks. antibody contains an FAB frag that is conjugated to PEG but lacks an Fc portion |
|
|
Term
| what are the 3 common antibiotics used in IBD therapy? |
|
Definition
| metronidazole, ciproflaxin, clarithromycin |
|
|
Term
| what type of drug is used to treat abdominal pain in IBS? |
|
Definition
| tricyclic antidepressants, no effect on mood at low doses, but appear to alter the processing of visceral pain information |
|
|
Term
| how do anti-spasmodics (anti-cholinergics) work? |
|
Definition
| inhibit muscarinic cholinergic receptors in the enteric plexus and on smooth muscle. |
|
|
Term
| what anti-spasmodics (anticholinergics) are used? what are the side effects? |
|
Definition
| dicyclomine (bentyl), hyosycamine (levsin); dry nose/mouth; visual disturbances; urinary retention (used only infrequently du/t AE) |
|
|
Term
| what are seratonin 5-HT3 receptor antagonists used for? (give specific one) |
|
Definition
| alosetron (lotronex); tx of severe diarrhea-predominant IBS in WOMEN. (50-60% report relief from pain, also reduces diarrhea) |
|
|
Term
| how do seratonin 5HT3 receptor antagonists work? |
|
Definition
| block 5HT3 receptors on enteric neurons to inhibit distension-induced sensory and motor reflex activation. also blocks central 5HT3 receptors to reduce responses to visceral stimulation. may also inhibit colonic motility. |
|
|
Term
| side effects of seratonin 5HT3 receptor antagonists |
|
Definition
| GI disturbances some of which are rare but serious. constipation (30%) and causes discontinuation in 10%. eschemic colitis in 0.3% --> fatal |
|
|
Term
| what are seratonin 5HT4 receptor agonists used for and how are they administered? (give specific name) |
|
Definition
| tegaserod (zelnorm) tx of constipation-prominent IBS. reduces abdominal pain, increases # of bowel movemnets per week, reduces hardness of stool. given orally, low bioavailability (10%) should be taken before meals since food reduces bioavailability. |
|
|
Term
| how do seratonin 5HT4 agonists work? |
|
Definition
| activation of 5HT4 receptors in mucosa stimulate peristalsis and gastric emptying. 5HT4 receptor activation also stimulates cAMP-dependent chloride secretion from colon --> increases stool liquidity |
|
|
Term
| side effects of seratonin 5HT4 receptor agonists |
|
Definition
| well tolerated. diarrhea (9%) resolves within first few days of tx. headaches (some) |
|
|
Term
| what is the drug used to tx gallstones and how does it work? |
|
Definition
| ursodial (actigall) = ursodeoxycholic acid, naturally occuring bile acid. decreases cholesterol content of bile by reducing hepatic cholesterol secretion. stabilizes hepatocite canalicular membranes |
|
|
Term
| who should take ursodial? |
|
Definition
| patients who are not candidates for gallstone surgery or who refuse cholecystectomy |
|
|
Term
| what are the luminal amebicides commonly used? what do they treat? |
|
Definition
| diloxanide furoate, iodoquinol, paromomycin; treat intestinal forms (only in lumen of bowel) |
|
|
Term
| what are the tissue (mixed) amebicides used? what do they treat? |
|
Definition
| metronidazole, tinidazole; intestinal and systemic (extraintestinal, bowel wall) forms treated, however less effective against amoeba in bowel lumen. |
|
|
Term
| what are the systemic amebicides used? what do they treat? |
|
Definition
| dehydroemetine, chloroquine; effective only against invasive forms, severe amebic dysentery or hepatic abscesses |
|
|
Term
| what is the tx for asymptomatic intestinal infection (amebiasis)? |
|
Definition
| luminal agent (80-90% effective); 10 day course 3x a day; check for no cysts in stool to prove cure |
|
|
Term
| what is the tx regimen for mild to moderate intestinal infection (amebiasis) |
|
Definition
| tissue agent + luminal agent; 90% effective (tx lumen, bowel wall and liver inf) check stool to make sure no cysts being passed |
|
|
Term
| what is the tx regimen for severe intestinal infection (amebiasis) with dysentery? |
|
Definition
| tissue agent + luminal agent; management of fluids and electrolytes necessary; opioids given to control bowel motility; give antidiarrheal to tx symptoms wil we wait for anti-protozoal to kick in |
|
|
Term
| what is the tx regimen for hepatic abscess in amebiasis? |
|
Definition
| tissue agent + luminal agent + chloroquine (recommended); metronidazole effective against anaerobes in abscess; must give luminal agent even if organism not detected in stool bc 10% relapse rate if luminal agent not given d/t latent infection |
|
|
Term
| what is the tx regimen for extraintestinal infection, ameboma? |
|
Definition
| tissue agent + luminal agent |
|
|
Term
| describe the use and administration of iodoquinol |
|
Definition
| oral; effective against trophozoites and CYSTS; used as monotherapy to treat asymptomatic intestinal infections or in combination with metronidazole for moderate to severe intestinal infection and extraintestinal infection. not well absorbed in the intestine (90% remains in bowel lumen --> reaches good therapeutic levels in lumen) |
|
|
Term
| what are the side effects of iodoquinol? |
|
Definition
| diarrhea (limited duration); nausea, vomiting, anorexia, abd pain, HA, rash, pruritis. may increase protein-bound serum iodine concentration leading to decreased iodine uptake and potential iodine deficiency. contraindicated in patients with intolerance to iodine; potential for NEUROtoxicity at higher than recommended dose. |
|
|
Term
| describe the use and administration of paromomycin |
|
Definition
| oral; aminoglycoside antibiotic; used as monotherapy for asymptomatic intestinal infections or in combination with metronidazole for more severe intestinal infections. not absorbed from GI tract (except with ulcerative intestinal lesions, impaired motility or intestinal obstruction) |
|
|
Term
| how does iodoquinol work? |
|
Definition
|
|
Term
| how does paromomycin work? |
|
Definition
| inhibition of protein synthesis |
|
|
Term
| side effects of paromomycin |
|
Definition
| safe if not absorbed. absorption occurs if bowel is perforated --> nephrotoxicity, ototoxicity, abdominal distress, diarrhea. drug should be avoided in patients with renal disease and used with caution in patients with GI ulcers |
|
|
Term
| describe diloxanide furoate use and administration |
|
Definition
| (only available thru CDC) oral; drug of choice for monotherapy for asymptomatic intestinal infections d/t low incidence of AE but no longer commercially available. used in combo with metronidazole for moderate to severe intestinal infections as well as extraintestinal inf. |
|
|
Term
| how does diloxanide furoate work? |
|
Definition
|
|
Term
| side effects of diloxanide furoate? |
|
Definition
| well tolerated (mild). flatulance (most common), nausea, vomiting, diarrhea, cramps, pruritis, urticaria |
|
|
Term
| describe the use and administration of metronidazole in protozoal infections |
|
Definition
| oral (90% bioavailability), IV, intravaginal, topical; potent antibac activity against anaerobes, drug of choice for trichomoniasis and giardia lamblia; used in combo with luminal agents to treat mild to seere intestinal ambeiasis and extraintestinal amebiasis; alternative to tetracyclin in tx of balantidium coli |
|
|
Term
| how does metronidazole work against protozoa? |
|
Definition
| prodrug --> hydroxymethyl metronidazole (reduced to active form in protozoa and anaerobes) --> reacts with DNA. only active against trophozoites |
|
|
Term
| side effects of metronidazole |
|
Definition
| nausea, vomiting, dry mouth, metallic taste, anorexia, abd pain; CNS probs with prolonged therapy (seizures, peripheral neuropathy, avoid in patients with CNS disease esp seizure disorders); metabolites potentially mutagenic (contraindicated in first trimester of preg, enters fetal circ rapidly, breast feeding not rec); disulfram like side effects (inhibits alcohol dehydrogenase, ethanol avoided); candida overgrowth; pancreatitis (serious, rare); leukopenia (rare, use with caution in patients with previous or active bone marrow suppression) |
|
|
Term
| when can tinidazole substitute for metronidazole? |
|
Definition
| amebiasis, giardia, trichomoniasis |
|
|
Term
| describe the use and administration of dehydroemetine |
|
Definition
| subcutaneous, IM (NEVER IV); alternative component of combination therapy (with luminal agent) in patients who dont respond to or are contraindicated for metronidazole use. used to treat severe intestinal amebiasis or extraintestinal amebiasis; works in ALL tissues |
|
|
Term
| how does dehydroemetine work? |
|
Definition
| inhibition of protein synthesis |
|
|
Term
| side effects of dehydroemetine? |
|
Definition
| cardiotoxicity (arrhythmias, conduction defects); prolongs QT, PR, QRS, ST) hypotension 25%. not a front line drug d/t these AE, metronidazole is preferred |
|
|
Term
| describe use and administration of chloroquine |
|
Definition
| oral, parenteral; used in combination therapy to treat amebic LIVER abscesses. much less effective against intestinal amebiasis bc only attains low concentrations in the intestinal wall. |
|
|
Term
| mechanism of chloroquine action |
|
Definition
|
|
Term
| side effects of chloroquine |
|
Definition
| well tolerated. pruritis (most common, esp africans), nausea, vomiting, abd pain, HA, anorexia, malaiase, blurring vision, urticaria. dosing after meals to reduce AE |
|
|
Term
| how/why is tetracycline used against protozoa? |
|
Definition
| used as an alternative to metro in multi-drug regimens in mild to severe intestinal amebiasis. (only for infections of the bowel wall). has only weak amebicidal actions, alters GI flora needed for amebic proliferation. |
|
|
Term
| what do we use to treat balantidium coli? |
|
Definition
| tetracycline (alternatives: metro, iodoquinol) |
|
|
Term
| what do we use to treat cryptosporidium parvum? |
|
Definition
| paromomycin or nitazoxinade (alternative: azithro) |
|
|
Term
| what do we use to treat cyclospora cayentanensis? |
|
Definition
|
|
Term
| what do we use to treat giardia lamblia? |
|
Definition
| metronidazole or nitazoxinade (alternative: tinidazole, furazolidone, albendazole) |
|
|
Term
| what do we use to treat isospora belli? |
|
Definition
|
|
Term
| what do we use to treat microsporidia? |
|
Definition
|
|
Term
| what do we use to treat trichamona vaginalis? |
|
Definition
|
|
Term
| what do we use furazolidone for and how does it work? |
|
Definition
| alternative to metro in tx of giardia lamblia. damages worm DNA; given orally with good bioavailability |
|
|
Term
| side effects of furazolidone? |
|
Definition
| nausea, vomiting, diarrhea, fever; disulfram-like activity (no etoh); acts as monoamine oxidase inhibitor (hypertensive crisis can be induced by increased norepinephrine availability following tx with sympathomimetics) |
|
|
Term
| describe the use and administration of nitazoxanide |
|
Definition
| oral (prodrug --> tizoxanide); tx giardia and cryptosporidium, effective against metronidazole resistant protozoal strains |
|
|
Term
| nitazoxanide mechanism of action? |
|
Definition
| its active metabolite (tizoxanide) inhibits the pyruvate:ferredoxin oxidoreductase pathway |
|
|
Term
| side effects of nitazoxanide? |
|
Definition
| well tolerated. metabolites free of mutagenic effects (lower risk for preg or breast feeding women than metro) |
|
|
Term
| describe the use and administration of TMP-SMX in protozoal tx |
|
Definition
| used to treat cyclospora cayentanensis and isospora belli |
|
|
Term
|
Definition
| disrupts folic acid synthetic pathway |
|
|
Term
| what do we use to treat ascaris lumbricoides? |
|
Definition
| mebendazole or albendazole or pyrantel pamoate (alternatives: ivermectin, piperazine) |
|
|
Term
| what do we use to treat enterobius vermicularus? |
|
Definition
| mebendazole or albendazole or pyrantel pamoate |
|
|
Term
| what do we use to treat hookworms? |
|
Definition
| mebendazole or albendazole or pyrantel pamoate |
|
|
Term
| what do we use to treat strongyloides? |
|
Definition
| ivermectin (alternatives: albendazole or thiabendazole) |
|
|
Term
| what do we use to treat trichuris trichura)? |
|
Definition
| mebendazole or albendazole (alternative: ivermectin) |
|
|
Term
| what do we use to treat trichinella spiralis? |
|
Definition
| mebendazole or albendazole (add corticosteroids for severe inf to reduce the stimulation of the immune response by antigens released by dying worms) |
|
|
Term
| what do we use to treat schistosoma? |
|
Definition
|
|
Term
| what do we use to treat clonorchis sinensi? |
|
Definition
| praziquantal (alternatives: mebendazole or albendazole) |
|
|
Term
| what do we use to treat diphyllobothrium latum? |
|
Definition
| praziquantal or niclosamide (not available in US) |
|
|
Term
| what do we use to treat taenia saginata? |
|
Definition
| praziquantal or niclosamide (not avail in US) alt: mebendazole |
|
|
Term
| what do we use to treat taenia solium? |
|
Definition
| praziquantal or niclosamide (not avail in US) |
|
|
Term
| what do we use to treat cysticercosis? |
|
Definition
| albendazole (alt: praziquantal) - albendazole is effective >80% for cystericosis secondary to T solium. it is the ONLY agent used for tx of ocular neurocystericosis |
|
|
Term
| how does mebendazole work? |
|
Definition
| irreversibly and selectively damages helminth microtubules --> accumulation of catabolic enzymes --> cell autolysis --> worm death. loss of microtubules also decreases glucose uptake --> starves worm --> contributes to death. |
|
|
Term
| how is mebendazole administered? |
|
Definition
| oral: poor bioavailability, minimal absorption and significant first pass metabolism |
|
|
Term
| contraindications for mebendazole use? |
|
Definition
| not for preg women or children <1 year old |
|
|
Term
| albendazole mechanism of action? |
|
Definition
| similar to mebendazole (damages helminth microtubules, decreases glucose uptake) |
|
|
Term
| albendazole mechanism of action? |
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Definition
| similar to mebendazole (damages helminth microtubules, decreases glucose uptake) |
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|
Term
| contraindications for albendazole use? |
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Definition
| not for preg women, breastfeeding women, or kids <2. should be monitored carefully if co-treated with theophylline, phenytoin or digoxin |
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|
Term
| pyrantel pamoate is the drug of choice for which 3 worms? |
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Definition
| ascaris, enterobius, hookworm |
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Term
| how does pyrantel pamoate work? |
|
Definition
| acts on helminth neuromuscular junction by inhibiting acetylcholinesterase and stimulates acetylcholine release --> paralysis --> worm released from intestinal wall --> GI peristalsis expels the worms |
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|
Term
| how is pyrantel pamoate administered? |
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Definition
| oral; poorly absorbed from GI tract, more than 50% excreted unchanged in feces |
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Term
| ivermectin is the drug of choice for? |
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Definition
|
|
Term
| how does ivermectin work? |
|
Definition
| potentiates the opening of glutamate-gated chloride channels found in nematodes but not humans --> paralysis of worms pharyngeal muscle --> death of parasite. also potentiates gaba-mediated inhibitory synaptic transmission in peripheral nerves --> contributes to paralysis (flaccid paralysis vs pyrantel pamoate which is tense paralysis) |
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|
Term
| how is ivermectin administered? |
|
Definition
| oral, single dose usually sufficient to expel worms in over 80% of patients. repeated dosing will increase cure rate |
|
|
Term
| contraindications for use of ivermectin? |
|
Definition
| pregnant women, not for patients with possible impairments of the BBB (i.e. meningitis) bc of GABA effects |
|
|
Term
| how does piperazine work? |
|
Definition
| blocks acetylcholine at the neuromuscular junction --> muscle paralysis --> dislodged and expelled by normal peristalsis |
|
|
Term
| contraindications for use of piperazine? |
|
Definition
| pregnant women, impaired renal or hepatic function, hx of epilepsy or chronic neurological disease (can cause neurotoxicity in rare cases) |
|
|
Term
| how does thiabendazole work? |
|
Definition
| interfere w/microtubule aggregation thru inhibition of fumurate reductase (ovicidal effects?) |
|
|
Term
| side effects of thiabendazole? |
|
Definition
| (7-50%) midl and transient, can be severe. nausea, vomiting, anorexia, dizziness...drowsiness, diarrhea, pruritis, neuropsych sx, hepatic dysfunc (rare) |
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|
Term
| contraindications for thiabendazole use? |
|
Definition
| pregnant woman, daytime use limited d/t drowsiness/dizziness; patient should be monitored carefully if co-treated with theophylline or other xanthine derivatives |
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|
Term
| how is praziquantal given? |
|
Definition
| oral; single dose usually effective |
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|
Term
| how does praziquantal work in general? |
|
Definition
| increases permeability to calcium ions and damages integument |
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|
Term
| describe how praziquantal works in schistosomiasis |
|
Definition
| increases permeability to calcium ions --> calcium influx induces tetanus and paralysis of worm muscles --> rapid and powerful vacuolation of tegument --> adult worms swept to liver, endocytosed by phagocytes. praziquantel exposes worm antigens and facilitates the IR, should not be given in acute schistosome disease (katayama) d/t additonal antigenic burden from dying immature worms which may exacerbate sx. |
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|
Term
| how does praziquantal work in tapeworms (diphyllobothrium, taenia saginata and solium) |
|
Definition
| increases permeability to calcium ions --> calcium release from intracellular stores --> massive worm contraction --> expulsion from GI |
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|
Term
| how is praziquantal administered? |
|
Definition
| oral; single dose, must be swallowed w/o chewing d/t bad taste. enters CSF, bile, breast milk |
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|
Term
| contraindications for use of praziquantal? |
|
Definition
| pregnant women, breast feeding discontinued for 72 hrs following tx. |
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|
Term
| what is the risk in treating t.solium with niclosamide? |
|
Definition
| viable ova are released by drug-damaged worms into the intestine --> can develop into larvae and cause cysticercosis |
|
|
Term
| how does niclosamide work? |
|
Definition
| uncoupling of worm oxidative phosphorylation --> increase ATPase activity --> starves worm |
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|
Term
| how is niclosamide giveN? |
|
Definition
| oral; single dose, minimal GI absorption |
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