Drugs to Treat Acute Aortic Dissection Flashcards
How do beta blockers work in treating aortic dissection?
- Blocking effects of Epi
- Cause heart to beat slower and with less force (lowers BP)
- Opens veins and arteries up to help improve blood flow
What is the MOA of LabetaloL?
- Blocks both alpha and beta receptors
- Decreases peripheral vascular resistance
What are some contraindications of labetalol?
- Overt cardiac failure
- Greater than first degree heart block
- Severe bradycardia
- Cardiogenic shock
- Severe hypotension
- Anyone with history of obstructive airway disease including asthma
What are some adverse effects of labetalol?
- Dizziness
- Tingling scalp or skin
- Lightheadedness
- Excessive tiredness
- Headache
- Upset stomach
- Stuffy nose
What are some precautions to take when prescribing labetalol?
- Hepatic injury
- Cardiac failure
- Exacerbation of ischemic heart disease following abrupt withdrawal
- Non-allergic bronchospasm
- Pheochromocytoma
- DM and hypoglycemia
- Major surgery
- Impaired hepatic function
- Jaundice or hepatic dysfunction
What are the drug interactions with labetalol ?
- TCAs: tremor
- Beta receptor agonist
- Drugs in patients with bronchospasm
- Cimetidine
- Halothane anesthesia
- Nitroglycerin
- Calcium antagonists
- DIgitalis glycosides (increase risk of bradycardia)
What is a specific population you have to be careful about when giving labetalol?
- Nursing mothers due to a small amount being able to be excreted in breast milk
- Pediatric patients: safety and effectiveness have not been identified yet
- Geriatric patients: orthostatic symptoms could arise
When are peak plasma levels of labetalol reached?
- 1 to 2 hours after oral administration
What can increase the bioavailability of labetalol?
- Taking with food
Where is labetalol found in the body?
- Plasma protein binding (50%)
- Breast milk
- Crosses placenta
How is labetalol metabolize?
- Mainly through conjugation to glucuronide metabolites
- Excreted in urine (55-60% appear in urine)
- Excreted via bile into the feces
How do you advise patients when taking labetalol?
- Take exactly as prescribed
- Do not interrupt or discontinue without physician’s advice
- Consult a physician at any signs or symptoms of impending cardiac failure or hepatic dysfunction
- Transient scalp tingling may occur
What does esmolol do in the heart?
- Affects the response to nerve impulses in heart
- Heart beats slower means there is a lower BP
What is the MOA of esmolol?
- Class II antiarrhythmic
- Competitively blocks response to B1 adrenergic stimulation
What is esmolol used for?
- To control rapid heart beats or abnormal heart rhythms
- Also used to treat fast heartbeat and tachycardia during surgery, after surgery, or during other medical procedures
What are some contraindications of esmolol?
- Bronchial asthma
- Overt cardiac failure
- Cardiogenic shock
- Severe sinus bradycardia
- Other conditions associated with severe and prolonged hypotension
- Hypersensitivity to product
- History of obstructive airway disease
- Heart block greater than first degree
- Decompensated heart failure
- IV administration of CCBs near giving esmolol
- Pulmonary hypertension
What are pregnancy considerations with esmolol?
- Could cause fetal bradycardia
- Monitor during pregnancy if beta blocker is given to mom
- Newborns should be monitored for 48 hours after birth
Is a mom allowed to breastfeed while taking esmolol?
- It isn’t known for sure if esmolol is present but due to short half life, one would have to decide after monitoring baby
What does esmolol do in the geriatric patient?
- Bradycardia which may require dosage reductions
What are some adverse effects of esmolol?
- Anaphylactic reactions
- Extravasation
- Hyperkalemia
- Hypotension (can occur during surgery)
What is the MOA of nitroprusside?
- Increases intracellular production of cGMP which causes vascular smooth muscle relaxation (dilation)
What happens to nitroprusside in the blood?
- Sodium nitroprusside breaks down and binds to oxyhemoglobin
What does oxyhemoglobin release after sodium nitroprusside is bound?
- NO
- Cyanide (toxic)
- Methaemoglboin
What are the indications of nitroprusside?
- Lowers BP immediately
- Reduces bleeding during surgery
- Treats acute CHF
What are some contraindications of nitroprusside?
- Not to be used for compensatory HTN
- Not in patients with inadequate cerebral circulation
- Not in patients who are near death
- NOt in patients with B12 deficiency, anemia, severe renal disease, and hypovalemia
What is worrisome about the use of nitroprusside?
- Cyanide being released
- Watch for conditions that have high cyanide ratios (Leber’s optic atrophy or tobacco amblyopia)
What are some common adverse effects of nitroprusside?
- Bradyarrhythmias
- Hypotension
- Palpitations
- Tachyarrhythmias
- Apprehension
- Restlessness
- Confusion
- Dizziness
- Cyanide poisoning
- Thiocyanate toxicity
What can be administered in order to reduce the chance of cyanide toxicity?
- Sodium thiosulfate
- Increases the rate of cyanide processing but may be toxic at high doses
What are some precautions to take with nitroprusside?
- Cyanide toxicity
- Check thiocyanate levels
- Monitor pulse oximeter
- Consideration of methemoglobinemia and thiocyanate toxicity
What is the black box warning on nitroprusside?
- Not suitable for direct injection
- Hypotension may occur leading to irreversible ischemic injury or death
- Cyanide toxicity
How many cyanide ions are made from metabolism of nitroprusside?
- One molecule of sodium nitroprusside makes four (4) CN- ions
How is cyanide excreted?
- Reacts with thiosulfate to produce thiocyanate and then excreted in urine
What is the MOA of nicardipine?
- Calcium entry blocker
- Inhibits the influx of calcium ions into cardiac and smooth muscle
What are the indications of nicardipine?
- Short term treatment of HTN
- Prolonged control of BP
What is a contraindication of nicardipine?
- Not to be used in those with advanced aortic stenosis
What are some adverse effects of nicardipine?
- Headache
- Hypotension
- Tachycardia
- Nausea/vomiting
What are some warnings associated with nicardipine?
- Monitor BP and HR
- Can increase frequency, duration, or severity of angina
- Use in patients with heart failure: Possible negative inotropic effects
- Use in patients with impaired hepatic function
- Use in patients with impaired renal function
What should you do with nicardipine in geriatric patients?
- Use low initial doses due to decreased hepatic and renal function
What are some drug interactions with nicardipine?
- beta blockers
- Cimetidine
- Cyclosporine
- Tacrolimus
How is nicardipine metabolized?
- CYP450 enzymes (CYP3A4)
- Transporters (P-GP substrate)
