Raises metabolic rate, stimulates heart, and promotes growth and development of nervous system and skeletal muscle.
T4 is converted to T3
TRH from hypothalamus ----> TSH from anterior pituitary -------> T3 & T4 from thyroid ------> inhibit TSH from anterior pituitary
Low T3 or T4 increases TSH, high T3 or T4 lowers TSH
Myxedema in adults
Cretinism in children
Goiter; puffy, expressionless face; cold/dry skin; brittle hair; hair loss from scalp & outer ½ of eyebrows; fatigue; irritability; depression; lack of concentration; cold intolerance; constipation; heavy menses; increased cholesterol
Permanent neuropsychological deficits, lower IQ, need replacement early in pregnancy
Mental retardation, large tongue, pot belly, dwarfish stature, derangement of growth - nerves, muscles, bone, teeth
TSH decreases to normal levels
Tachycardia, angina, tremor, nervousness, insomnia, hyperthermia, heat intolerance, sweating
Colestyramine (Questran), colestipol (Colestid), sucralfate (Carafate), calcium supplements, aluminum –containing antacids, iron supplements.
Levothyroxine increases the degradation of Vitamin K-dependent clotting factors and may increase chance of bleeding. May need to decrease dose of warfarin.
Levothyroxine increases the body’s response to epinephrine, norepinephrine, and dopamine.
Rapid onset of action in myxedema coma.
Life-long replacement; monitor for S&S of hypothyroidism & hyperthyroidism; hold levothyroxine if pulse >100/min & call primary care provider; monitor TSH, T3 & T; minimize adverse drug interactions
Severe tachycardia, heart failure, hyperthermia, profound weakness, coma.
Thyroid-stimulating immunoglobulins (TSI)
Rapid, strong heartbeat; rapid thoughts & speech; trouble concentrating; tremor; insomnia; weakened muscles; increased body temperature; warm, moist skin; increased appetite with weight loss; diarrhea; exophthalmos
Inhibits thyroid hormone synthesis by inhibiting peroxidase. Suppresses conversion of T4 to T3 in the periphery.
Agranulocytosis – may see sore throat or fever
Inhibits thyroid hormone synthesis but does not block T4 or T3 in the periphery.
Inhibits synthesis and release of thyroid hormones.
Brassy taste, burning of mouth, sore gums & teeth, may get severe abdominal pain
Hold if >100/min
Mucus – forms a barrier to protect underlying cells from gastric acid and pepsin.
Bicarbonate – neutralizes any acid which penetrates the mucus.
Blood flow – maintains integrity or health of the mucosa
Prostaglandins – Stimulates mucus and bicarbonate, vasodilates blood vessels, suppresses gastric secretion
Heliobacter pylori (H. pylori) – gram-negative bacillus which lives between the mucus layer and the mucosa. Produces CO2 and ammonia from urea which damages the mucosa.
NSAIDs – decreases the production of prostaglandins which decreases blood flow, decreases bicarbonate and mucus secretion, and increases gastric acid.
Gastric Acid – injures cells of the mucosa and activates pepsin.
Pepsin – breaks down protein of the gut wall.Smoking – delays healing of ulcers and increases risk of recurrence.
Binds gastric acid and forms a neutral salt, inactivates pepsin if pH > 5, and stimulates prostaglandins.
1 and 3 hrs after meals and at bedtime, 1 hour before another drug, or every 2 hours if not eating
Aluminum hydroxide and sodium bicarbonate – heart failure, magnesium hydroxide – CNS toxicity in renal patients
Block H2 receptors on parietal cells which suppress gastric acid secretion and decrease the hydrogen ion concentration in gastric acid.
May be taken without regard to meals, except take Tagamet with food
Which histamine-2 receptor antagonist is known for its ability to block androgen effects?
Decreased gastric acid production
Before a meal – Nexium (1 hr), Prilosec, and Prevacid; doesn’t matter for the others
How long does it take for full recovery of the H+, K+-ATPase pump after stopping a proton pump inhibitor?
Why is misoprostol (Cytotec) used?
What are the mechanisms of action?
Stimulates uterine contractions.
Polymerization and cross-linking occurs when the pH is < 4. It adheres to the crater for 6 hours. Give 1 g before meals and bedtime or 2 g BID
1 hour between an antacid and sucralfate.
2 hours between drugs and sucralfate.
2-3 antibiotics with a proton pump inhibitor or histamine-2 receptor antagonist
Disrupts the cell wall of H. pylori, inhibits urease, and keeps H. pylori from adhering to the mucosa. Black tongue and stools.
pH 5, > pH 6-7
5-6 small meals per day. Bland food does not promote healing. Caffeine may not interfere with healing.
Black, tarry stools and coffee-ground vomitus.