Pharm Exam 4 (antiemetics, endocrine meds)

vomiting & meds*

-VC (vomiting center) and CTZ (chemoreceptor trigger zone)

—these are spots in the brain that are triggered → vomit

—meds work by blocking these pathways (blocking neurotransmitters & receptors) in brain and GI tract

-meds for chemo and post-op N/V: neurokinin antagonists, serotonin blockers, tetrahydrocannabinoids

-MONITOR F&E

-med AEs:

—drowsiness (caution driving)

• less w/ ondansetron & dronabinol

—CNS depression (w/ alcohol)

—ohTN (precautions)

antidopaminergics*

-block dopamine receptors in brain (CTZ) & GI

-also calms CNS and tx psychotic problems and hiccups

-AEs: ohTN, tachycardia, TD, HA, blurry vision, dry eye, urine retention, dry mouth, N/V, anorexia, constipation

—worse w/ CNS depressants & alcohol

-e.g.

—promethazine

—prochlorperazine (contra: phenothiazine hypersensitivity, coma, seizures, encephalopathy, bone marrow suppression)

—droperidol (used less often b/c it causes dysrhythmias)

promethazine / Phenergan*

-antidopaminergic

-AE: sedation

-contra: under age 2

-PO, IM, rectal suppository

-IV

—do NOT give in artery, will cause tissue injury requiring amputation

—check patency before! extravasation risk

—dilute in >10 mL fluid, give via large bore

—d/c if pt reports pain or burning

serotonin blockers*

-block receptors in brain and GI (CTZ & VC)

-good for N/V from chemo or post-op

—give 30 mins before treatment or end of surgery

-AEs: HA, diarrhea, rash, bronchospasm, long QT

-interacts w/ SSRIs

-e.g. ondansetron

—also tx hyperemesis gravidarum (not in first trimester, causes cleft palate)

—PO, IV

anticholinergics

-block ACh receptors in inner ear & block stimuli to CTZ & VC

-e.g. scopolamine (TD patch placed 4 hr before surgery or travel, lasts 72 hr)

antihistamines

-H1 receptor blockers

-inhibit ACh by binding H1 receptors

-also tx motion sickness, nonproductive cough, allergy S/S, sedation

-e.g. dimenhydrinate, diphenhydramine, meclizine

neurokinin receptor antagonists*

-inhibit substance P and neurokinin receptors in brainstem

-used w/ serotonin blockers & glucocortoids

—for chemo N/V

-e.g. aprepitant, fosaprepitant

tetrahydrocannabinoids*

-psychoactive substance in marijuana

-inhibit reticular formation, thalamus, and cerebral cortex

-alter mood and perception to decrease N/V

-for chemo N/V and anorexia from AIDS

-e.g. dronabinol

other antiemetics

-phosphorated carbohydrate solution (Emetrol)

—mint-flavored oral solution for morning sickness

-ginger

—may help chemo N/V and morning/motion sickness

—AEs: anorexia, N/V, skin reaction

—increases risk of bleeding w/ anticoagulants

levothyroxine*!

-T4 thyroid hormone replacement: increases BMR, O2 consumption, temp, BV, cell growth, & number of cardiac beta-adrenergic receptors (→ increases CO)

—increases GFR to causes diuresis

-tx hypothyroidism

-give QD in morning 30-60 min before breakfast (prevents insomnia & food interactions)

-PO, IM, IV

-dosed in mcg

-measure effectiveness by checking TSH levels

—also: thickened skin, hair loss, constipation, lethargy, and anorexia should improve

—goal is normal TH levels (“euthyroid”)

levothyroxine problems*

-contra: recent MI, adrenal insufficiency, hyperthyroidism

-interact: increase effects of anticoagulants & digoxin, decrease effects of antidiabetics, effects decreased by food

-AEs: tachycardia, palpitations, angina, HTN, insomnia, tremors, HA, anxiety, N/V/D, cramps, menstrual irregularities, sweating, heat intolerance, weight loss, fever

—OD S/S: dysrhythmias, irritability, tachycardia, insomnia

antithyroid meds*!

-for hyperthyroidism, also to prevent TH surge after thyroid surgery

-give w/ food at same time QD

-avoid iodine-rich foods (seafood, tofu, salt, soy sauce)

-e.g. radioactive iodine, PTU, methimazole

-watch for S/S to improve: diarrhea, weakness, insomnia, fatigue, palpitations, nervousness, heat intolerance

—may take 2 wk

problems with antithyroid meds*

-interact: increase effects of bone marrow suppressants, increase anticoagulant effects

-AEs: drowsiness, HA, vertigo, paresthesias, N/V/D, hepatitis, loss of taste, smoky urine, decreased UO, low WBC/plt, bleeding, rash/itch, myalgia, nephritis

-contra: cardiac disease, HTN

—caution: pregnancy (adjust dosage q4wk)

adrenal meds*!

corticosteroids

-mineralcorticoids: increase sodium resorption → fluid retention → increase BP

—increase K+ and H+ excretion

—e.g. aldosterone

-glucocorticoids: similar to mineralcorticoids; also decrease inflammation & immune response, increase protein catabolism, cause glycogenesis and lipolysis, increase BGM, cause bone demineralization

*suffix “-sone” or “-olone”

uses for adrenal meds*

-adrenal deficiency

-meningitis, TB

-cerebral edema

-SLE

-dermatitis, pemphigus

-thyroiditis

-UC, enteritis

-asthma or COPD exacerbation, rhinitis

-bleeding tendencies

-ophthalmic disorders

-post-organ transplant (decrease immune response)

-palliative for leukemia & lymphoma

-tx proteinuria from nephrotic syndrome

-spinal cord injury

adrenal med problems*!

-contra: cataracts, glaucoma, PUD, mental health problems, DM, infections, gastritis, GERD

—cardiac, renal, or liver dysfunction

-AEs:

—electrolyte imbalances → HF, edema, HTN, high Na+, low K+

—misc: convulsions, HA, vertigo, weakness, osteoporosis, IIOP & glaucoma, cataracts, immunosuppression

—mental: mood swings, psych problems, nervousness, insomnia

—hormonal: delayed growth, Cushing’s (adrenal oversecretion), menstrual irregularities, hyperglycemia, central weight gain

—GI: PUD, pancreatitis, UC, abd distention

—skin: petechiae, ecchymosis, hirsutism, hives, delayed wound healing, moon face

nursing for adrenal meds*!

-interact:

—increase hypocalcemia and hypokalemia from potassium-wasting diuretics

—increase GI ulcers w/ NSAIDs and aspirin

—decrease immune response w/ immunizing biologics

—decrease effects of oral antidiabetics

—cause weakness in myasthenia gravis pt w/ anticholinesterases

-do not abruptly d/c (→ adrenal crisis/suppression)

-avoid taking long-term

-take in morning (to minimize adrenal suppression), w/ food

-never given SUBQ, do not give topical on face

-monitor pt in hospital for AE: psychosis

fludrocortisone / Florinef*

-mineralcorticoid

-for Addison’s disease (adrenal insufficiency)

-contra: systemic fungal infection

-AEs: HF, HTN, IICP (→ seizures), hypokalemia, bone fractures, thrombophlebitis, high BGM, rash, PUD, muscle pain/weakness

-avoid vaccines (increases risk of neuro AEs)

examples of glucocorticoids*

-prednisone

—helps decrease inflammation and immune response

—tx chronic respiratory illness exacerbation

—PO

-methylprednisolone

—similar uses to prednisone

—IV

—contra: neonates