Pharmacology Review Flashcards

Antianginals

• Antianginals are drugs used to treat angina, a type of chest pain caused by reduced blood flow to the heart.

• The goal of antianginal drugs is to reduce the workload on the heart, either by:

  • Reducing afterload (the resistance the heart pumps against).

  • Reducing preload (the amount of blood returning to the heart).

• Nitrates are a class of antianginal drugs that work by:

  • Dilating veins, which reduces venous return and preload.

  • Dilating arterioles, which reduces afterload.

  • Dilating capacitance vessels, which increases venous pooling of blood.

  • Dilating the ischemic zone to improve blood flow.

Nitrates

• Nitroglycerin comes in forms such as sublingual tablets, translingual spray, Nitro-Bid tabs (patch), and ointments.

• Nitrates can have quick onset and short duration or slow onset and sustained release.

• Nursing Considerations

  • Monitor for:

    • Severe Hypotension

    • Tachycardia

    • Dizziness

    • Headache

    • Syncope

Adverse Effects of Nitrates

• Central Nervous System

  • Throbbing headache (> 50%, can be severe)

  • Dizziness, vertigo, lightheadedness (5%)

  • Syncope (0.4%, with high doses).

• Cardiovascular System

  • Flushing of the face (common, with rapid-acting preparations, likely due to the local production of prostaglandins).

  • Palpitations (with high doses).

  • Postural hypotension (frequent).

  • Profound hypotension (if taken concomitantly with sildenafil, a specific cGMP phosphodiesterase-5 inhibitor. The interaction can be life-threatening).

• Other systems

  • Skin rashes, contact dermatitis (rare)

  • Methemoglobinemia (with nitrite or with toxic doses of nitrates) (very rare)

  • Withdrawal reactions (digital vasospasm, coronary spasms, myocardial ischemia, myocardial infarction)

  • Drug abuse (with amyl nitrite)

Renal Physiology

• Kidney:

  • Weight: 0.5% of body weight

  • Receives 25% of cardiac output

  • Filtration organ of the body

• Kidney Functions

  • Balance of electrolytes, plasma volume, acid-base

  • Activation of Vitamin D

  • Synthesis of Erythropoietin

  • Excretion of Urea, Uric acid, Creatinine etc.

Diuretic Types

• Osmotic Diuretic

  • mannitol (Osmitrol)

    • Mechanism: Shifting of fluid from intracellular to extracellular.

    • Clinical Use: Glaucoma, cerebral edema

    • Side Effects: Hyponatremia, hypovolemia

    • Special Points:

      • Potent

      • Caution with HF or Renal failure patients

      • Used in Glaucoma, poisoning, to decrease intracranial pressure.

• Loop Diuretics

  • furosemide (Lasix), bumetanide (Bumex)

    • Clinical Use: Think “HE” (Heart Failure, Hypertension, Edema)

    • Side Effects: Think “Hypo” (Hyponatremia, Hypokalemia, Hypomagnesemia, Hypovolemia, Hypotension), Ototoxicity, hyperuricemia

    • Special Points:

      • Most potent diuretic

      • Most Potent is Bumetanide

      • Monitor for Sulfa allergies

      • Headache & dizziness due to low BP

      • Dehydration

• Thiazide Diuretics

  • hydrochlorothiazide (HCTZ)

    • Clinical Use: Think “CHIC” (Congestive Heart Failure (CHF), Hypertension, Insipidus, Calcium Calculi)

    • Side Effects: Think “Hyper” (Hyperglycemia, Hyperlipidemia, Hyperuricemia, Hypercalcemia), Hypovolemia, Hypotension

    • Special Points:

      • Moderate diuretic

      • Blocks calcium & uric acid excretion

      • First line in Hypertension

      • Inhibits sodium and chloride reabsorption

      • Monitor for hyperglycemia, hypokalemia, hypotension

• Potassium Sparing Diuretics

  • spironolactone (Aldactone)

    • Side Effects: Hyperkalemia

    • Special Points:

      • Weak diuretic

      • Should not combine with other potassium supplements

      • Caution taken with ACE inhibitors or ARBs – can cause dangerous hyperkalemia

Nursing Implications: Diuretics

• Monitor intake and output.

• Monitor potassium loss.

• Monitor weight and vital signs.

• Monitor for hearing loss.

• Teach patient to take medication early in the day to reduce chances of nocturia.

• Teach patient to report hearing loss or gout symptoms.

Potassium Rich Foods

• The Banana Spin Pot Song

  • I know=increase potassium; The Banana -BANANNAS; Spin= SPINACH; Pot- POTATOES; S- SALT SUBSTITUTES; O-ORANGE Citrus; N-NUTS; G-GRAPEFRUIT Citrus

Special Considerations for Diuretics

• Diuretics enhance the antihypertensive efficacy of multidrug regimens, can be useful in achieving BP control, and are more affordable than other anti-hypertensive agents.

• Don’t use diuretics overenthusiastically. (dehydration, hypotension)

• Diuretics not used in Toxemia (High BP) of Pregnancy. (Blood volume is low despite edema. Diuretics will compromise placental circulation)

• Most Loop and Thiazide diuretics are sulfonamide derivatives. (Think of allergic manifestations)

Hydrochlorothiazide (HydroDIURIL)

• Not responsible for lost potassium. Get your ticket for treatment and control of edema related to HF, cirrhosis, renal disease, and hypertension.

• Delivery routes: PO, IV, and IM

Furosemide (Lasix)

• Watch for BP, weight, I&O imbalance, Dehydration, K, Hyperglycemia

Brain Breaks

• Breaks for the classroom.

Antihypertensive Drugs

• Hypertension

Heart Anatomy

• SUPERIOR VENA CAVA: FROM UPPER BODY

• INFERIOR VENA CAVA: FROM LOWER BODY

• PULMONARY ARTERY: TO RIGHT LUNG, TO LEFT LUNG

• PULMONARY VEINS: FROM RIGHT LUNG, FROM LEFT LUNG

Hypertension

• No Hypertension:

  • Heart Pumping Normally

  • Blood flows easily through vessels

• Hypertension:

  • Heart Pumping Harder

  • Blood may not flow easily through vessels

• Hypertension

  • Systolic Blood Pressure (SBP) > 140 mmHg

  • Diastolic Blood Pressure (DBP) > 90 mmHg

Types of Hypertension

• Essential:

  • A disorder of unknown origin affecting the Blood Pressure regulating mechanisms.

  • Environmental Factors: Stress, Na^+ Intake, Obesity, Smoking

• Secondary:

  • Secondary to other disease processes.

Antihypertensive Drug Classes

• SVR refers to systemic vascular resistance, SV refers to stroke volume, and calcium channel blockers refer to dihydopyridines

Overview of Diuretics

• Acetazolamide

  • A carbonic anhydrase inhibitor that inhibits the reabsorption of HCO_3 in the proximal convoluted tubule.

  • Weak diuretic properties.

• Thiazides

  • Inhibit reabsorption of Na^+ and Cl^- in the distal convoluted tubule, resulting in retention of water in the tubule.

  • Most commonly used diuretic for the treatment of hypertension.

• Spironolactone, Amiloride, Triamterene

  • Spironolactone, an aldosterone antagonist, inhibits the aldosterone-mediated reabsorption of Na^+ and secretion of K^+.

  • Amiloride and triamterene block Na^+ channels.

  • These agents can prevent loss of K^+ that occurs with thiazide or loop diuretics.

• Bumetanide, Furosemide, Torsemide, Ethacrynic Acid

  • The loop diuretics inhibit the Na^+/K^+/2Cl^- cotransport in the ascending loop of Henle, resulting in retention of Na^+, Cl^−, and water in the tubule.

  • These drugs are the most efficacious of the diuretics.

Antihypertensives

• Calcium Channel Blockers

  • amlodipine (Norvasc), verapamil (Calan), nifedipine (Procardia), diltiazem (Cardizem)

  • Watch for hypotension, peripheral edema, flushing, headache, and GI upset.

• Beta-Adrenergic Blockers

  • metoprolol (Lopressor), atenolol (Tenormin), propranolol (Inderal), nadolol (Corgard)

  • Watch for bradycardia hypotension, HF, bronchospasms, and diminished sexual function.

  • Nobody quits these guys without seeing a doctor first!

Stepped-Care Approach to Treatment of Chronic Hypertension

• STEP 1

  • Nonpharmacologic approaches

• STEP 2

  • Drug 1: diuretic or beta blocker or calcium channel blocker or angiotensin converting enzyme (ACE) inhibitor

• STEP 3

  • Increase dose of drug1 or add drug from other class or substitute drug from other class

• STEP 4

  • Add drugs from a different class or substitute drug from other class.

• STEP 5

  • Further evaluate or add 3rd or 4th drug

B-Blockers

• Propranolol (Inderal), Atenolol (Tenormin), Metoprolol (Lopressor)

  • (Ends in OLOL)

• Mechanism: Blocks Beta Receptors in The Heart Causing:
  * \downarrow Heart Rate
  * \downarrow Force of Contraction
  * \downarrow Rate of A-V Conduction

• Side Effects: Bradycardia, Lethargy, Gl Disturbance, CHF, \downarrow BP, Depression

Alpha-Adrenergic Antagonists (Alpha-Blockers)

• Examples: doxazosin (Cardura), prazosin (Minipress)

• Side Effects: Orthostatic Hypotension, Tachycardia, Vertigo, Sexual Dysfunction

ACE Inhibitors

• Angiotensin-converting enzyme (ACE) forms angiotensin II & causes the arteries to narrow. ACE inhibitors stop the ACE activity, thus relax the arteries and lower blood pressure.

  • Ends in APRIL

• Examples: captopril (Capoten), enalapril (Vasotec), benazepril (Lotensin)

• Actions: Peripheral vascular resistance without:
  * Cardiac output
  * \uparrow Cardiac rate
  * Cardiac contractility

• Side Effects: Dizziness, Orthostatic hypotension, GI distress, Cough, Headache

Angiotensin II Receptor Blockers (ARBs)

• ARBS lower blood pressure and increase blood to the heart.
  * Dilated artery=lower blood pressure
  * Opens coronary arteries
  * ARBs block angiotensin receptor

• Examples: Valsartan (Diovan), Losartan (Cozaar)

Calcium Channel Blockers

• Examples: nifedipine, verapamil, diltiazem

• Actions: Blocks calcium access to cells causing:
  * \downarrow Contractility.
  * \downarrow Conductivity of the heart
  * \downarrow Demand for oxygen

• Side Effects: \downarrow BP, Bradycardia
  * May precipitate AV block
  * Headache
  * Abdominal discomfort (constipation, nausea)
  * Peripheral edema