Pharmacology of NSAIDs and Hydrochlorothiazide

Drugs Affecting the Urinary and Immune System

• This lecture covers drugs affecting the urinary and immune systems.
• Learning objectives include describing kidney function, reabsorption/secretion processes, and the impact of renal failure on pharmacotherapy.
• It also covers indications for diuretics and the use of other urinary tract medications.

Urinary System

• The urinary system comprises the kidneys, ureters, urinary bladder, and urethra.
• Kidneys filter blood and excrete waste products, maintaining electrolyte and fluid balance.
• Reabsorption is the process of returning essential substances from the filtrate back into the blood.
• Secretion moves substances from the blood into the filtrate..
• Renal failure decreases kidney function, leading to drug accumulation and potential toxicity.

The Nephron

• The nephron is the functional unit of the kidney.
• It involves filtration, reabsorption, and secretion.
• Specific processes occur at the glomerulus, Bowman's capsule, proximal tubule, loop of Henle, distal tubule, and collecting duct.
• Filtration filters blood; reabsorption moves good substances into the blood; secretion moves wastes into the filtrate; excretion removes the waste from the body.

Reabsorption

• Reabsorption is crucial for regulating fluid and electrolyte balance.
• Water, glucose, amino acids, and essential ions are reabsorbed.
• The process occurs through the walls of the nephron.

Secretion

• Certain ions and molecules are secreted from the blood into the filtrate.
• Substances like potassium, phosphate, hydrogen, and ammonium ions are secreted.
• Some drugs are secreted through the proximal tubule.

Renal Failure

• Renal failure impacts pharmacotherapy significantly.
• Electrolyte and fluid balance are disrupted.
• Waste products accumulate, leading to toxicity.
• Can be acute or chronic.

Diuresis

• Diuresis is the increased production of urine.
• Drugs block sodium reabsorption, increasing sodium excretion.
• Chloride and water follow sodium, increasing urine volume.

Diseases Treated by Diuretics

• Diuretics are used to treat hypertension, heart failure, kidney failure, pulmonary edema, and liver failure/cirrhosis.

Diuretics (Types)

• Loop diuretics (act on the loop of Henle)
• Thiazide and thiazide-like diuretics (act on the distal tubule)
• Potassium-sparing diuretics (used cautiously, as they retain potassium)
• Other diuretics (osmotic agents, carbonic anhydrase inhibitors).

Loop Diuretics (e.g., Furosemide)

• Furosemide is a potent diuretic that acts on the loop of Henle.
• It inhibits sodium and chloride reabsorption.
• Often administered intravenously for rapid effect.
• Side effects can include fluid and electrolyte imbalances, hypokalemia, ototoxicity, and metabolic alkalosis.

Thiazides and Thiazide-Like Diuretics (e.g., Indapamide, Hydrochlorothiazide)

• Indapamide and Hydrochlorothiazide are weaker diuretics.
• They act on the distal tubule.
• Used primarily to treat mild to moderate hypertension.
• Side effects include fluid and electrolyte imbalances, hypokalemia, dehydration, and low blood pressure (BP).

Potassium-Sparing Diuretics (e.g., Spironolactone)

• Spironolactone blocks aldosterone receptors, conserving potassium.
• Used to treat hypertension, nephrotic syndrome, ascites, heart failure, and edema.
• Side effects include dizziness, headache, fluid and electrolyte imbalance, and breast tenderness.

Osmotic Diuretics (e.g., Mannitol)

• Mannitol acts on the proximal and descending loop of Henle.
• Promotes water diuresis, reducing swelling.
• Used for glaucoma and intracranial pressure reduction.

Carbonic Anhydrase Inhibitors (e.g., Acetazolamide)

• Acetazolamide reduces intraocular pressure, used to treat glaucoma.
• Also used to reduce swelling and treat intracranial hypertension.

Antispasmodics (e.g., Oxybutynin)

• Oxybutynin blocks muscarinic acetylcholine receptors, relaxing bladder muscles, reduced urgency and urination frequency.
• Indicated for overactive bladder and neurogenic bladder disorders.
• Side effects include dry mouth, urinary retention, dizziness, drowsiness and blurred vision.

Urinary Tract Analgesics (e.g., Phenazopyridine)

• Phenazopyridine provides local anesthetic effect on urinary tract mucosa to relieve burning pain associated with urinary tract irritations/infections/surgery/injury.

Immune System

• The immune system is a complex network of organs, WBCs, proteins, and chemicals.
• It differentiates foreign substances from non-foreign ones.
• It activates/mobilizes/attacks/kills foreign invaders.
• It learns about invaders after exposure to mount a future defense (antibodies).

Inflammation

• Inflammation is a body defense mechanism.
• It occurs in response to various stimuli.
• The purpose is to contain/destroy invaders, remove debris, and promote healing.
• The acute inflammatory response has distinct signs: swelling, pain, warmth, and redness.

Treatment of Inflammation

• Treatments can be non-pharmacological (e.g., RICE – rest, ice, compression, elevation) or pharmacological (e.g., NSAIDs, steroids).
• It's essential to identify the cause (e.g., injury, infection) so targeted treatment can be applied.

Anti-Inflammatory Drugs (e.g., NSAIDs, Corticosteroids)

• NSAIDs (e.g., ibuprofen, naproxen) block prostaglandin synthesis.
• Corticosteroids (e.g., prednisone) suppress the immune response.

Pathogens

• Pathogens are microorganisms (bacteria, viruses, parasites, fungi) that cause diseases.
• The immune system responds to pathogens in various ways.
• Types of germs that cause diseases (bacteria, viruses, protozoans, multicellular parasites, fungi).

Anti-Infective Drugs

• Anti-infective (antimicrobial) drugs target pathogen's metabolism and life cycle.
• Anti-infective drugs reduce or eliminate the pathogen.
• Example classes such as penicillin, cephalosporins, tetracyclines, macrolides, aminoglycosides, fluoroquinolones.

Patient Teaching

• Patient teaching is crucial to avoid complications and promote adherence to therapy.
• For all types of anti-infective drugs, it's important not to discontinue prematurely and not share medication.

Test your knowledge on the primary mechanisms of action and considerations for non-steroidal anti-inflammatory drugs (NSAIDs) and hydrochlorothiazide. This quiz covers important concepts including specific drug indications, potential adverse effects, and nursing considerations. Perfect for nursing and pharmacology students!