Cardiovascular System Antianginal Drugs Lilley Reading and Workbook

Cardiovascular System Antianginal Drugs Lilley Reading and Workbook – Chap 23

Antianginal Drugs Cardiac Ischemia Supply and Demand: ◦ When the supply of oxygen and nutrients in the blood is insufficient to meet the demands of the heart The heart requires a large supply of oxygen to meet the demands placed on it Ischemia ◦ Poor blood supply to an organ - myocardium Ischemic heart disease ◦ Poor blood supply to the heart muscle ◦ Atherosclerosis or Coronary artery disease Myocardial infarction (MI) ◦ Necrosis, or death, of cardiac tissue ◦ Disabling or fatal

Types of Angina Chronic stable angina (also called classic or effort angina) Unstable angina (also called preinfarction or crescendo angina) Vasospastic angina (also called Prinzmetal’s or variant angina)

Drugs for Angina Goal of Treatment Increase blood flow to ischemic heart muscle and/or Decrease myocardial oxygen demand Minimize the frequency of attacks and decrease the duration and intensity of angina pain Improve the patient’s functional capacity with as few adverse effects as possible Prevent or delay the worst possible outcome, MI

Drugs for Angina Nitrates/nitrites b(beta)-blockers Calcium channel blockers

Drugs for Angina Nitrates/Nitrites Available forms Sublingual* Buccal* Chewable tablets Oral capsules/tablets Intravenous solutions Ointments* Transdermal patches* Translingual sprays* *Bypass the liver and the first-pass effect

Drugs for Angina Nitrates/Nitrites Vasodilation due to relaxation of smooth muscles Potent dilating effect on coronary arteries Used for prevention and treatment of angina Vasodilation results in reduced myocardial oxygen demand Nitrates cause dilation of both large and small coronary vessels Nitrates alleviate coronary artery spasms Result: oxygen to ischemic myocardial tissue

Drugs for Angina Nitrates/Nitrites Rapid-acting forms ◦ Used to treat acute anginal attacks ◦ Sublingual tablets; intravenous infusion Long-acting forms ◦ Used to PREVENT anginal episodes

Nitroglycerin Drugs for Angina Nitrates/Nitrites Prototypical nitrate Large first-pass effect with oral forms Used for symptomatic treatment of ischemic heart conditions (angina) IV form used for BP control in perioperative hypertension, treatment of HF, ischemic pain, pulmonary edema associated with acute MI, and hypertensive emergencies

Drugs for Angina Nitrates/Nitrites isosorbide dinitrate (Isordil, Sorbitrate, Dilatrate SR) isosorbide mononitrate (Imdur, Monoket, ISMO) Uses: Acute relief of angina Prophylaxis in situations that may provoke angina Long-term prophylaxis of angina

Drugs for Angina Nitrates/Nitrites Adverse effects Headaches ◦ Usually diminish in intensity and frequency with continued use ◦ Treated with acetaminophen Tachycardia, postural hypotension Tolerance may develop

Drugs for Angina Nitrates/Nitrites Tolerance Occurs in patients taking nitrates around the clock or with long-acting forms Prevented by allowing a regular nitrate-free period to allow enzyme pathways to replenish ◦ Transdermal forms: remove patch at bedtime for 8 hours, then apply a new patch in the morning

Drugs for Angina Nitrates/Nitrites Nursing implications IV forms of NTG must be given with special non-PVC tubing and bags Discard parenteral solution that is blue, green, or dark red Follow specific manufacturer’s instructions for IV administration

Nitroglycerin Patient Education Instruct patients in proper technique and guidelines for taking sublingual NTG for anginal pain Instruct patients never to chew or swallow the SL form Instruct patients that a burning sensation felt with SL forms indicates that the drug is still potent Instruct patients to keep a fresh supply of NTG on hand; potency is lost in about 3 months after the bottle has been opened

Nitroglycerin Patient Education Medications should be stored in an airtight, dark glass bottle with a metal cap and no cotton filler to preserve potency Instruct patients in the proper application of nitrate topical ointments and transdermal forms, including site rotation and removal of old medication To reduce tolerance, the patient may be instructed to remove topical forms at bedtime and apply new doses in the morning, allowing for a nitrate-free period

Nitroglycerin Patient Education Instruct patients to take prn nitrates at the first hint of anginal pain Monitor VS frequently during acute exacerbations of angina and during IV administration If experiencing chest pain, the patient taking SL NTG should be lying down to prevent or decrease dizziness and fainting that may occur due to hypotension

Nitroglycerin Patient Education If anginal pain occurs: Stop activity and sit or lie down Take a SL tablet (as prescribed), If no relief of chest pain, call Emergency Services/911 immediately Do not try to drive to the hospital

b-Blockers atenolol (Tenormin) metoprolol (Lopressor) propranolol (Inderal) nadolol (Corgard)

b-Blockers (cont’d) Mechanism of action b 1 -receptors on the heart are blocked Decrease the HR, resulting in decreased myocardial oxygen demand increased oxygen delivery to the heart Decrease myocardial contractility, helping to conserve energy or decrease demand After an MI, a high level of circulating catecholamines irritate the heart, causing an imbalance in supply and demand ratio and even leading to life-threatening dysrhythmias. b-blockers block the harmful effects of catecholamines, thus improving survival

b-Blockers (cont’d) Indications Angina Antihypertensive Cardiac dysrhythmias Cardioprotective effects, especially after MI Some used for migraine headaches, essential tremors, and stage fright

b-Blockers (cont’d) Adverse effects Body System Cardiovascular Metabolic CNS Other Adverse Effects Bradycardia, hypotension, second- or third-degree heart block; heart failure Altered glucose and lipid metabolism Dizziness, fatigue, mental depression, lethargy, drowsiness, unusual dreams Impotence, wheezing, dyspnea

b-Blockers Nursing implications Patients taking b-blockers should monitor pulse rate daily and report any rate lower than 60 beats per minute Dizziness or fainting should also be reported Constipation is a common problem; instruct patients to take in adequate fluids and eat high-fiber foods These medications should never be abruptly discontinued due to risk of rebound hypertensive crisis Inform patients that these medications are for long-term prevention of angina, not for immediate relief

Calcium Channel Blockers (cont’d) Mechanism of action Cause coronary artery vasodilation Cause peripheral arterial vasodilation, decreasing systemic vascular resistance Reduce the workload of the heart Result: decreased myocardial oxygen demand

Calcium Channel Blockers (cont’d) Indications First-line drugs for treatment of angina, hypertension, and supraventricular tachycardia Coronary artery spasms (Prinzmetal’s angina) Short-term management of atrial fibrillation and flutter Raynaud’s Phenomenon Adverse effects Very acceptable adverse effect and safety profile May cause hypotension, palpitations, tachycardia or bradycardia, constipation, nausea, dyspnea (other adverse effects possible

Calcium Channel Blockers Patient Education Constipation is a common problem Patients should: take in adequate fluids Eat high-fiber foods

Nursing Implications Before administering, perform a complete health history to determine presence of conditions that may be contraindications for use or call for cautious use Obtain baseline VS, including respiratory patterns and rate Assess for drug interactions Patients should not take any medications, including OTC medications, without checking with the physician Patients – encourage to limit caffeine intake

Patients should report blurred vision, persistent headache, dry mouth, dizziness, edema, fainting episodes, weight gain of 2 pounds in 1 day or 5 or more pounds in 1 week, pulse rates less than 60, and any dyspnea Alcohol consumption and hot baths or spending time in whirlpools, hot tubs, or saunas will result in vasodilation, hypotension, and the possibility of fainting Teach patients to change positions slowly to avoid postural BP changes Encourage patients to keep a record of their anginal attacks, including precipitating factors, number of pills taken, and therapeutic effects

Antianginal Drugs: Nursing Implications Monitor for adverse reactions ◦ Allergic reactions, headache, lightheadedness, hypotension, dizziness Monitor for therapeutic effects ◦ Relief of angina, decreased BP, or both

Review A 62 -year-old patient is having an anginal attack but avoids taking his prescribed PRN dosage of nitroglycerin. Appropriate nursing actions would include: (Select all that apply. ) 1. having him take the prescribed dose immediately. 2. asking him why he avoids taking the dose as soon as the pain starts. 3. giving him a thorough explanation of the purpose(s) or value of taking the medication. 4. reprimanding him severely for his hesitancy in self-administering the nitroglycerin

Review Instruct the patient on the proper storage of nitroglycerin to keep the medicine in: 1. a chest pocket for easy access. 2. its container for 6 months. 3. the original, dark-colored glass container. 4. its container in the refrigerator to reduce deterioration.

Review Calcium channel blockers reduce anginal pain by: 1. promoting vasodilatation and minimizing cellular aggregation. 2. increasing the heart rate and blood pressure. 3. stimulating peripheral vasoconstriction. 4. increasing peripheral resistance