Renal and GI Function Quiz

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Questions and Answers

Which statement correctly describes COX-2's role in vascular function?

COX-2 inhibition decreases vascular prostaglandin levels resulting in faster clotting. (correct)

COX-2 increases prostacyclin production which leads to vasodilation. (correct)

COX-2 is constitutively active primarily in the kidneys and brain.

COX-2 is responsible for producing thromboxane A2, promoting vasodilation.

What is a direct consequence of aspirin intake in patients with asthma?

Reduced thromboxane A2 activity enhancing platelet aggregation.

Increased risk of bronchospasm due to cysteinyl leukotrienes. (correct)

Decreased levels of prostaglandins leading to airway relaxation.

Enhanced production of mucus and bicarbonate secretion.

How do non-selective NSAIDs impact platelet function?

They inhibit both TXA2 and prostacyclin, potentially leading to thrombotic events. (correct)

They only inhibit TXA2 without affecting prostacyclin production.

They enhance the vasodilatory effects of prostacyclin in the endothelium.

They selectively inhibit COX-2, enhancing clotting through TXA2.

What is the consequence of COX-1 stimulation in gastric cells?

Secretion of protective prostaglandins in the gastric mucosa. Signup and view all the answers

What warning was issued by the FDA regarding NSAIDs as of 2015?

Non-aspirin NSAIDs are linked to higher risks of heart attacks or strokes. Signup and view all the answers

What is the primary action of COX-2 selective agents?

Inhibit COX-2 at inflammation sites Signup and view all the answers

Which statement about ibuprofen is false?

It is safe for use during pregnancy. Signup and view all the answers

How does acetaminophen differ from traditional NSAIDs?

It has no anti-inflammatory effects Signup and view all the answers

What is a notable risk associated with COX-2 selective agents?

Increased risk of thrombotic events Signup and view all the answers

What is the primary concern associated with the use of ketorolac?

It poses a risk of severe gastrointestinal and renal effects. Signup and view all the answers

Why might naproxen require dosage adjustments in elderly patients?

Its half-life is doubled in elderly individuals. Signup and view all the answers

What therapeutic effect is primarily associated with acetaminophen?

Analgesic and antipyretic effects Signup and view all the answers

Which statement about naproxen is incorrect?

It is less effective than ibuprofen for treating acute pain. Signup and view all the answers

What is a consequence of COX inhibitors in marginally functioning kidneys?

Reduction in renal function Signup and view all the answers

How do prostaglandins (PGs) influence uterine contractions?

They directly induce contractions Signup and view all the answers

What effect does PGE2 have in the nervous system during inflammation?

It causes hyperalgesia at inflammation sites Signup and view all the answers

Which characteristic is true about organic acids, excluding Nabumetone?

They accumulate at sites of inflammation. Signup and view all the answers

Which medication is contraindicated for children with viral-induced fever due to the risk of Reyes syndrome?

Aspirin (salicylates) Signup and view all the answers

Which statement best describes the cardiovascular risks associated with higher doses of NSAIDs?

Increased risk of hypertension and heart failure is associated with prolonged high doses. Signup and view all the answers

What is the primary analgesic action of NSAIDs thought to be related to?

Blocking hyperalgesia via central and peripheral mechanisms Signup and view all the answers

What is the effect of late pregnancy NSAID administration on the patent ductus arteriosus in newborns?

It causes premature closure leading to pulmonary hypertension. Signup and view all the answers

Study Notes

Housekeeping Functions and Cytoprotective PGs

Renal blood flow, GI function, mucosal proliferation, and platelet function are regulated by the housekeeping function.
Prostaglandins (PGs) in the GI tract provide cytoprotection.

COX Enzyme Functions

COX-2 is induced during inflammation and is essential for renal development and brain function.
COX-2 mediates vascular production of prostacyclin, which causes vasodilation.
COX-1 is constitutive in gastric cells, producing PGs that protect epithelial and parietal cells.

Smooth Muscle Responses

Vascular actions: Thromboxane A2 (TXA2) induces vasoconstriction while PGE2 and PGI2 act as vasodilators.
Airways: PGE2 and PGI2 relax smooth muscle, whereas TXA2 and PGF2α cause contraction. Leukotrienes (LTs) also contribute to contraction.

Asthma and NSAID Effects

In asthma, NSAIDs (like aspirin) can provoke bronchospasm and dyspnea due to excess production of cysteinyl leukotrienes.

Gastrointestinal Considerations

NSAIDs frequently cause gastrointestinal distress, bleeding, and gastritis due to inhibited acid production and altered mucus/bicarb secretion.
COX-2 and acetaminophen (Tylenol) generally have fewer GI side effects.

Platelet Function and Thrombotic Risks

COX-2 in endothelial cells produces PGI2, which inhibits platelet aggregation; inhibiting COX-2 may increase clotting risks.
COX-1 stimulates TXA2, increasing clotting risk in myocardial infarction; low-dose aspirin effectively blocks TXA2.

FDA Warnings for NSAIDs

Non-aspirin NSAIDs can elevate the risk of heart attacks or strokes by 10-50%, necessitating updated warnings, particularly at high doses and extended durations.

Kidney Function and NSAIDs

COX inhibitors can impair renal function, worsen hypertension, and exacerbate congestive heart failure.

Uterine Function of Prostaglandins

Prostaglandins stimulate uterine contractions and can induce labor; NSAIDs may prolong labor.
They maintain patent ductus arteriosus in utero; NSAIDs can cause premature closure if administered late in pregnancy but assist in ductus closure post-premature birth.

Nervous System Effects of Prostaglandins

PGE1 and PGE2 raise body temperature via hypothalamic action.
PGEs inhibit norepinephrine release, potentially leading to increased vasoconstriction when NSAIDs are used.
PGE2 can cause hyperalgesia at inflammation sites, with NSAIDs providing acute relief.

General Characteristics of NSAIDs

Organic acids (except Nabumetone) accumulate in inflamed tissues.
Most NSAIDs have reversible effects, with aspirin having a unique long-lasting effect.

Shared Therapeutic Effects of NSAIDs

NSAIDs are utilized for inflammation reduction (acetaminophen is an exception), antipyretic effects, and analgesia.
Aspirin is contraindicated in children for viral-induced fever due to the risk of Reye's syndrome; acetaminophen is preferred.

Ibuprofen (Motrin)

Typical dosing is 400 mg every 4-6 hours, adjustable up to 3200 mg per day.
Recommended to be taken with food to mitigate GI side effects; half-life is about 2 hours.
Newly approved IV formulation for patients unable to tolerate oral medications.

Naproxen (Aleve)

Fully absorbed with a peak effect in 2-4 hours; half-life is 14 hours.
Elderly patients require dosage adjustments due to increased serum concentrations.
Associated with a heightened risk of cardiovascular events, warranting FDA warnings.

Ketorolac (Toradol)

Potent analgesic, effective for postoperative pain, used for short-term pain relief, not for chronic management.
Increased potency corresponds to greater risk of adverse effects on the GI tract and renal function.

COX-2 Selective Agents

These agents specifically inhibit COX-2, providing anti-inflammatory, analgesic, and antipyretic effects with fewer GI complications.
Celecoxib (Celebrex) is more selective for COX-2, showing efficacy comparable to traditional NSAIDs, without prothrombotic effects at therapeutic doses.

Acetaminophen (Tylenol)

Used as an alternative to aspirin for analgesia and fever reduction; raises pain thresholds and affects hypothalamic function for antipyretic action.
Lacks peripheral COX inhibition, showing no anti-inflammatory effects and little impact on platelets or uric acid levels.

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Description

Test your understanding of renal and gastrointestinal housekeeping functions, including blood flow and mucosal proliferation. This quiz covers the roles of prostaglandins and their effects on vascular smooth muscle and airways, especially in the context of inflammation and asthma.