Pharm Exam 2 Flashcards
What are 6 muscarinic agonists?
acetylcholine, methacholine, carbachol, Bethanechol, muscarine, pilocarpine
What happens to Ach with the use of anticholinesterases?
Ach concentrations increase; these prevent the breakdown of Ach into choline and acetate
What are some reversible anticholinesterases?
edrophonium, neostigmine, pyridostigmine, rivastigmine, donepezil, galantamine
What are some irreversible anticholinesterases?
insecticides- malathion, diazinon, chlorpyrifos
nerve gases- sarin, tabun, soman
What are some therapeutic uses for anticholinesterases?
atonic bladder and GI tract, glaucoma, reversal of neuromuscular blockade, myasthenia gravis, Alzheimer’s disease
What is the preferred agent for paralytic ileus and atony of the urinary bladder?
neostigmine; peristalsis is fast when given subcutaneously
What is the mechanism of action of anticholinesterase when treating glaucoma?
there is contraction of ciliary muscle which allows aqueous humor to flow out -> decreasing intraocular pressure
Why is echothiophate not typically used in glaucoma?
it has been associated with the development of cataracts
What is myasthenia gravis?
autoimmune neuromuscular disorder characterized by significant skeletal muscle weakness; appears to result in decrease in ACh receptors
What is the tensilon test?
uses the drug tensilon to diagnose myasthenia gravis; tensilon is an anticholinesterase which helps prevent the break down of ACh which in turn helps stimulate the muscles; a patient has myasthenia gravis if muscles get stronger after being injected with Tensilon
What is the treatment for myasthenia gravis?
Physostigmine q2-4h; Neostigmine q3-6h; Ambenonium q3-8h
What is the pathophysiology behind Alzheimer’s Disease?
patients demonstrate a loss of neurons particularly cholinergic types
What is typically used to treat Alzheimer’s Disease?
donepezil, rivastigmine, galantamine; side effects include nausea, vomiting, diarrhea
What will be apparent in contact with organophosphates?
SLUDGE
How can one treat organophosphate poisoning?
administer atropine and pralidoxime STAT; remove all contaminated clothing immediately; wash skin with soap and water; rinse eyes with plain water for 10-15 min; maintain airway; do not induce vomitting
Where does acid production occur?
parietal cells
what receptors are on parietal cells?
gastrin, acetylcholine, histamine
Where does acetylcholine come from?
vagal stimulation of postganglionic enteric neurons
Where does gastrin come from?
G cells
Where does histamine come from?
ECL cells
What is a negative effect of antacids?
can impair absorption of iron and some antibiotics; decreases stomach acidity can impair the body’s ability to absorb protein, carbs, fats, vitamins A.E.C, folate, micro-trace elements, and minerals
What H2-receptor antagonist is not available IV?
nizatidine
What H2-receptor antagonist is most potent and most selective?
famotidine- with a duration of action of 10-12h
What excretes H2-Receptor Antagonists and why is this important?
the kidneys- must reduce the doses in people that have impaired renal functions
What side effects occur primarily with IV administration of H2-Recepto Antagonists?
mental status changes such as confusion
What are general side effects of H2-Receptor Antagonists?
diarrhea, headache, fatigue, constipation
What are the major therapeutic uses of H2-Receptor Antagonists?
promote healing of gastric and duodenal ulcers, treat GERD, and prevent occurrence of stress ulcers
What are the most potent suppressors of gastric acid secretion?
inhibitors of the gastric H+, K+-ATPase proton pump; proton pump inhibitors
What is the basic mechanism behind a PPI?
when activated the prodrug irreversibly binds to H+/K+-ATPase inactivating the pump molecule
After using a PPI what causes acid secretion to resume?
acid secretion can only resume after a new pump molecule has been synthesized and inserted into the luminal membrane
What is a downfall of a PPI?
they are highly sensitive to degradation by acid- therefore they are supplied in delayed release acid-resistant capsules or enteric-coated tablets
What happens to a PPI when given with food?
the bioavailability is decreased by 50%; should be given 1 hour prior to meal
What cytochromes are used by PPIs?
CYP3A4 and CYP2C19
Why is CYP2C19 a concern in PPIs?
Asians are more likely to have the CYP2C19 genotype that correlates with slow metabolism of PPIs
Are all PPIs equally protective?
Yes, when using equal doses
What are some general adverse effects of PPIs?
diarrhea, headache, stomach pain; these things occur only in a low percentage of patients
What is a adverse effect concerning the clearance of a PPI?
PPIs are metabolized and cleared by hepatic CYPs- therefore may interfere with other drugs cleared by this route
What is Clopidogrel?
Plavix- decreases platelet aggregation in people who have had a stroke, MI, recent CABG, or stent replacement; it is a prodrug that requires CYP2C19 to be converted to its active form
What is the drug interaction between a PPI and Clopidogrel?
PPIs have been shown to decrease the conversion of Clopidogrel to its active form therefore when taken with the use of PPIs Clopidogrel does not convert to its active anticoagulating form
What PPIs may be taken with Clopidogrel, but only if absolutely necessary?
rabeprazole or pantoprazole
What infection is a person at a higher risk of acquiring with the use of a PPI?
increased risk of nosocomial pneumonia; also increased risk of C.Diff infection; this is because gastric acid is an important barrier to intestinal infection
When should sucralfate be administered?
on an empty stomach an hour before food
How does sucralfate work?
binds selectively to ulcers and erosions like a bandage
How does misoprostol work?
it is a prostaglandin E1 analog; stimulates mucus and bicarbonate secretion and increases mucosal blood flow; modestly decreases acid secretion (not a major effect)
How many times a day is misoprostol give?
3-4 times a day because of a short half life
How is misoprostol excreted?
renally but does not require a dose adjustment
What are the adverse effects of misoprostol?
diarrhea, cramping in 10-20% of patients, can cause miscarriage, no drug interactions
How does bismuth subsalicylate work?
it coats erosions and ulcers but does not adhere like sucralfate; may increase productions of prostaglandins, bicarbonate, and mucous
What are the adverse effects of bismuth subsalicylate?
blackening of the stool, darkening of the tongue; high deses over long periods could cause salicylate toxicity; caution in renal impairment
What is another use of bismuth subsalicylate?
it decreases stool frequency and liquidity in acute infectious diarrhea; antimicrobial effects of bismuth beneficial in H. pylori infection and travelers diarrhea
What should be given if GERD symptoms are 3 or less times a week?
an antacid or H2-blocker prn
What should patients with severe symptoms of GERD (asthma, chronic couch, laryngitis, noncardiac chest pain) use?
a PPI bid for 3 months
What should be given with frequent symptoms of GERD?
H2-blocker bid; PPIs are superior particularly in more severs cases with erosion
In peptic ulcer disease what are the benefits of an H2-blocker?
provide nocturnal coverage which helps in healing; can give qhs for 6-8 weeks and healing typically occurs with 80-90% of patients
When are PPIs the drug of choice?
when you want to achieve rapid healing, 90% of duodenal ulcers were healed in 4 weeks and gastric ulcers were healed in 6-8 weeks
How should ulcers caused by NSAIDs be treated?
discontinue NSAID use, and give a PPI qd (once a day)
How should H. pylori ulceration be treated?
only PPI is effective in treating these ulcers and eradicating the H. pylori
How should stress ulcers be treated in the critically ill?
H2-blockers are preferred IV (due to cost and proven efficacy); an exception is that if a patient has an NG tube you should use immediate release oral omeprazole (PPI)
What is an example of a D2 Receptor Antagonist?
metoclopramide (Reglan)
How is metoclopramide available?
orally and parenterally
What are the uses for metoclopramide?
minimally effective in gastroparesis; potent anti-nausea and anti-vomiting due to D2 receptor blockade in chemoreceptor trigger zone as well as some mild 5-HT3 activity; used in GERD as an adjunct only; used post-surgically to delay gastric emptying
How is a D2 Receptor Antagonist excreted?
urine; must dose adjust for renally impaired patients
What is the half life for D2 receptor antagonists?
4-6 hours with a duration of action 1-2 hours
What are some adverse effects of D2 receptor antagonists?
extrapyramidal side effects due to lack of dopamine; increase prolactin levels (galactorrhea, gynecomastia, impotence, menstrual irregularities), tolerance to treatment is common
What is erythromycin?
macrolide antibiotic; motilin is a potent contractile agent of the upper GI tract; effects of motilin can be mimicked by erythromycin
What are the adverse effects of erythromycin?
nausea, vomiting, abdominal pain, tolerance develops to treatment within a few weeks, possibility of C. diff infection, drug interactions,
What are the symptoms of constipation?
less than 3 stools a week, straining, hard, dry stools, feeling as though there is incomplete emptying of bowel
What are bulk forming laxatives composed of?
indigestible hydrophilic colloids that absorb water
What is the mechanism of a bulk forming laxative?
distension of colon triggering peristalsis
What are the side effects of bilk forming laxatives?
bloating and gas; may prevent absorption of other drugs
What are the functions of the thyroid gland?
oxygen consumption, heat production, carb fat and protein metabolism, growth and differentiation, stimulation of other hormones
What is the first step in biosynthesis of thyroid hormones?
uptake of iodine by NIS (sodium iodide symporter)
What is organification?
oxidation of iodide and iodination of thyroglobulin tyrosyl groups to form monoiodotyrosyl (MIT, T1) or diiodotyrosyl (DIT, T2)
What are some of the clinical effects of thyroid hormones on growth an development?
there is a significant role in neurogenesis and skeletal formation
cretinism- a congenital hypothyroidism (maternal hypothyroidism) resulting in severely stunted growth and mental retardation
What are the clinical effects of thyroid hormones on cardiovascular functions?
increases heart rate, contractility, cardiac output, myocardial O2 consumption, diastolic relaxation, vasodilation
What are the clinical effects of thyroid hormones associated with metabolic functions?
stimulates conversion of cholesterol to bile acids, enhances glucose uptake by cells and generation of free glucose
What are some general clinical effects associated with thyroid hormones?
mental acuity, reproduction, thermogenesis in warm-blooded species
What are the effects of excess thyroid hormone?
A-fib, CHF, Osteoporosis, vision loss in severe cases, thyrotoxic crisis
What are the effects of inadequate thyroid hormone?
goiter (constant increased levels of TSH result in hypertrophy), increased LDL, CHF, cardiovascular disease, depression, peripheral neuropathy, myxedema, infertility, birth defects
What are some of the causes of hypothyroidism?
hashimoto’s thyroiditis, drug-induced, dyshormonogenesis, radiation, x-ray, thyroidectomy, congenital (cretinism), secondary (TSH deficit)
Goiters are present in what causes of hypothyroidism?
in hashimoto’s thyroiditis they present early and absent later, drug-induced, dyshormonogenesis, congenital they can be absent or present
In hypothyroidism what are the patients complaints?
fatigue, dry skin, hair loss, depression, mental slowness, poor, memory, constipation, cold intolerance, weight gain, fluid retention, muscle aches, stiffness, menstrual irregularities, infertility
As a provider what do we find in our observations in hypothyroidism?
goiters, bradycardia, delayed refluxes, hypertension, edema, periorbital puffiness, abdominal distention, decreased systolic and increased diastolic, pale, dry skin
When do you expect to reach a steady state with levothyroxine?
4-6 weeks
What is levothyroxine?
a synthetic T4 for the treatment of hypothyroidism
What is the half life of levothyroxine?
7 days, dosing is once daily dosing
What are the aging fluctuations concerning Levothyroxine?
aging, large fluctuations in body weight, and pregnancy require reevaluation of dose; pregnant patients require increased doses, infants and children require more T4 than adults, adults over 65 may require even less, in patients who have unusually high requirements consider gastritis, H. Pylori, or celiac
What is Liothyronine?
synthetic T3, but do not pick this drug; T3 can lead to toxicity and there is no evidence that using T3 in hypothyroidism is beneficial
What is Dessicated thyroid?
not considered first line, there are problems in protein antigenicity, stability, variability in hormone levels, no long-term safety data
What is the most common cause of hyperthyroidism?
Graves disease
What are some of the causes of hyperthyroidism?
graves disease, toxic multinodular goiter, toxic adenoma, thyroiditis or inflammation of the thyroid gland, TSH secreting pituitary adenoma, metastatic tumors
What are patient complaints with hyperthyroidism?
weight loss, anxiety, sweating, diarrhea, heart palpitations, muscular weakness, heat intolerance, tremor
As a provider what would be our observations seeing someone with hyperthyroidism?
warm moist skin, Proptosis, conjunctival irritation, blepharospasm, tachypnea, goiter, tremor, hyperactive reflexes, tachycardia
What are some treatment options for someone with hyperthyroidism?
surgical thyroidectomy, destruction of gland with radioactive iodine, Antithyroid drugs-thioamides- methimazole or PTU
What are Antithyroid drugs?
used in young patients with mild disease, pregnancy category D, inhibit iodine organification, effects are seen in 4 weeks or more because you must deplete all T4 stores in the body due to inhibition of synthesis but not release
What is Propylthiouracil?
hyperthyroidism…used in pregnancy (more protein binding than methimazole, doesn’t cross placental barrier as easily), thyroid storm; half life is 1.5 hours but this doesn’t indicate therapeutic effect due to accumulation in thyroid gland; severe hepatitis may occur; given q8h; additional benefit of preventing T4 to T3 conversion in periphery, brings levels down faster than methimazole
What is methimazole?
hyperthyroidism… 1st choice except in pregnancy and thyroid storm; half life is 6 hours but doesn’t indicate therapeutic effect due to accumulation in thyroid gland; less risk of liver damage; cholestatic jaundice is more common than with PTU; often give tid until euthyroid then proceed with once daily dosing
What are the side effects of thioamides?
Common: nausea, GI disturbance, altered sense of taste or smell (methimazole), rash, fever
Rare: urticaria rash, Vasculitis, Polyserositis
Life threatening: agranulocytosis, hepatitis (PTU)
What are additional treatments for hyperthyroidism?
iodides- used to decrease gland size prior to surgery and treatment of thyroid storm
radioactive iodide- 131I is the only form used for destruction of thyroid, but dangerous is given to pregnant or nursing moms
propranolol- for treatment of symptoms in acute phase, diltiazem if beta blocker is contraindicated
What are Langerhans?
areas of endocrine tissue that secrete hormones into the blood: insulin, glucagon, islet amyloid polypeptide (APP amylin), somatostatin, gastrin, pancreatic peptide
What percent of the islets of Langerhans do B cells make up?
75%
What is diabetes mellitus?
condition of elevated glucose due to absent or impaired insulin secretion with or without impaired ability to utilize insulin
What is somatostatin?
universal secretory inhibitor
What is islet amyloid polypeptide?
modulates appetite, gastric emptying, glucagon/insulin release
What are the functions of insulin in the liver?
inhibits of glycongenolysis, inhibits of ketogenesis, promotes glycogenesis
What are the functions of insulin in the muscle?
increases protein synthesis, increases glycogen synthesis, increases uptake of glucose
What are the functions of insulin in the adipose tissue?
increases triglyceride storage, inhibits breakdown of fat, increases fat storage
What is type 1 diabetes?
characterized by beta cell destruction resulting in severe to absolute insulin deficiency; primarily autoimmune; patients require exogenous insulin to survive- lack of insulin will result in diabetic ketoacidosis; obesity is not a factor
What is type 2 diabetes?
characterized by insulin resistance- inability to suppress hepatic glucose production, peripheral glucose uptake is impaired; strong correlation with obesity; definite genetic component; ketosis is typically not a concern; does not require insulin initially; nonketotic hyperosmolar syndrome via dehydration in combination with poorly controlled diabetes is a life threatening emergency
What are some symptoms of diabetes?
polyuria, polydipsia, polyphagia, extreme fatigue, weight loss even with increased food intake (type 1)
What are some complications of uncontrolled DM?
cardiovascular disease including atherosclerosis, MI, and stroke; neuropathy from mild tingling to numbness and potential limb loss; neuropathy may progress to renal failure requiring dialysis; retinopathy leading to blindness; difficulty healing; UTI, yeast infections; ketoacidosis in type 1; nonketotic hyperosmolar syndrome type 2
How does insulin secretion work?
presence of glucose at the beta cell leads to ATP production resulting in closure of the potassium channel and cell depolarization; cell depolarization opens calcium channel; calcium influx stimulates insulin release via exocytosis
What are the available preparations for exogenous insulin?
rapid-acting, short-acting, intermediate-acting, long-acting
What is the goal of therapy with exogenous insulin?
simulate normal basal and stimulated insulin secretion
What are the rapid-acting insulin drugs?
insulin lispro, insulin aspart, and insulin glulisin
What is rapid-acting insulin?
it stimulates prandial endogenous insulin release; it has the lowest absorption variability of all insulin; given immediately before a meal; the duration of action is not more than 3-4 hours; preferred for use in insulin pumps
What are the short-acting insulin?
regular insulin (humulin R, novolin R); injected as hexamers which have slowest absorption then eventually dissociate to dimers and eventually monomers which have fastest uptake; onset is 30 min, peak is 2-3 hours, duration is 5-8 hours; given 30-45 minutes before a meal
What are intermediate-acting insulin drugs?
NPH (Humulin N, Novolin N); onset is 2-5 hours, peak is 6-10 hours, duration is 10-16; unpredictable action and variable absorption; seen mixed with rapid or short acting formulations and given 2-4 times a day
What is a long acting insulin drug?
glargine (lantus, toujeo); detemir (Levemir)
How does a glargine long acting insulin drug work?
forms crystalline depot in the skin where insulin molecules slowly leach out into circulation
Toujeo vs. Lantus
toujeo is 3 times more potent than lantus with a slower release of insulin to improve 24 hour coverage
What is a contraindication of Glargine?
it cannot be mixed with other insulins because it will precipitate out in less acidic formulations
What is detemir?
a long acting insulin drug that is formulated to self-aggregate in subcutaneous tissue for slow release as well as bind to albumin reversibly; onset is 1-2 hours, duration 12 hours; dosed bid to maintain steady background insulin
What is an insulin mixture?
NPH may be mixed in the same syringe with lispro, aspart, or glulisine immediately before injection to achieve short and longer term coverage
What is a complications of insulin therapy?
hypoglycemia
causes: mismatched carb:insulin ratio and increased physical exertion
warning signs: tachycardia, palpitation, sweating, tremor, nausea, hunger, may progress to seizures or coma
correction of hypoglycemia occurs with glucose administration
What is another complication of insulin therapy?
insulin allergy: rare, urticaria results from histamine release from mast cells sensitized by anti-insulin IgE antibodies ; allergy is due to protein contaminants; human and analog insulins have resulted in decreased allergy
What is another complication of insulin therapy?
immune insulin resistance: most insulin treated patients develop low IgG anti-insulin antibody titers over time that neutralize effects of insulin; occasionally antibodies lead to insulin resistance
When is continuous subcutaneous infusion delivery for insulin used?
used with rapid acting insulins
What are the Antidiabetic agents that stimulate insulin secretion from beta cells?
insulin secretagogues: sulfonylureas, meglitinides, D-phenylalanine derivatives
How does the termination of action of catecholamine metabolism occur?
1) diffusion away from terminal
2) reuptake by NET
3) uptake by other tissues
What are the effects of acetylcholine on the cardiovascular system?
vasodilation, negative chronotrope (rate), negative inotrope (force), negative domotrope (conduction velocity)
What are the effects of acetylcholine on the respiratory tract?
bronchoconstriction, increase secretion, stimulation of carotid and aortic bodies
What are the effects of acetylcholine on the urinary tract?
detrusor muscle contraction, increased voiding pressure, ureteral peristalsis
What are the effects of aetylcholine on the GI tract?
increased tone, increased amplitude of contractions, increased secretions in stomach and intestine
What are some additional effects of acetylcholine?
miosis, increased lacrimal, nasopharyngeal, salivary secretions, increased production of sweat