Pharmacology for Stroke Flashcards
Drug example of beta-blocker for stroke
Labetalol (Trandate)
Labetalol (Trandate) MOA
Blocks stimulation of beta 1 and beta 2 adrenergic receptor sites. Also has blocking effect on alpha 1 receptor sites.
Indication for Labetalol (Trandate)
Management of hypertension
Therapeutic effect of labetalol (Trandate)
Decreased blood pressure
Adverse effects of labetalol (Trandate)
Fatigue, weakness
Bronchospasm
Arrhythmias, bradycardia
Congestive heart failure, pulmonary edema
Orthostatic hypotension
Precautions for labetalol (Trandate)
Allergies/ hypersensitivity
Heart failure
Pulmonary edema and pre-existing obstructive lung diseases
Bradycardia and heart blocks
Use cautiously in renal and liver dysfunction
Nursing considerations for labetalol (Trandate)
Administer with meals to increase absorption
Frequent monitoring of BP and pulse
Take apical pulse prior to admin, if <50bpm, hold and notify physician
Assess for orthostatic hypotension
Monitor intake/ output
Daily weights
Assess for signs of fluid overload (lung crackles, weight gain, edema, fatigue)
When receiving intravenous labetalol…
High alert medication → can be very dangerous
Patient must lay supine for 3 hours after admin
Vitals assessed q5-15 minutes during and after admin
Stroke specific info: labetalol
Commonly used in acute phase of stroke
Blood pressure usually rises following a stroke → thought to be a protective response to maintain cerebral perfusion
We only administer BP meds in ischemic stroke if the BP is extremely high
In order to administer thrombolytic therapy
Systolic BP must be less than 185 mmHg and diastolic BP must be less than 110 mmHg
If patient is not receiving thrombolytics for an ischemic stroke, then patient only requires antihypertensive if…
Systolic BP > 220 mmHg and diastolic > 120 mmHg
For hemorrhagic stroke, administer antihypertensive if…
Systolic > 160 mmHg
Patient education for labetalol (Trandate)
Abrupt withdrawal of labetalol can cause life threatening arrhythmias, hypertension, or myocardial infarction
Direct patient to make slow position changes → special caution when exercising, drinking alcohol, and in hot weather
Diabetic patients should have sugars monitored more closely → medication will mask warning signs of hypoglycemia (such as tachycardia)
What is cyclooxygenase?
Cyclooxygenase is an enzyme found in all tissues. It converts arachidonic acid into prostaglandins and other related compounds like thromboxane A2, also called TXA 2
What is COX 1?
COX 1 is found in almost all tissues and it is considered the “good cox”. It is like the housekeeper that protects many parts of the body.
How does COX 1 work?
It works in the stomach and protects the gastric mucosa by reducing gastric acid secretion and maintaining blood flow. It supports the kidneys by supporting renal blood flow. It promotes platelet aggregation by synthesizing thromboxane A2.
What is COX 2?
COX 2 comes into action during tissue injury. It mediates inflammation and sensitizes pain receptors. It also affects the brain where it facilitates fever and contributes to pain reception. It improves renal flow and dilate our blood vessels
What is the name for aspirin?
Acetylsalicylic acid
Acetylsalicylic acid MOA
Suppresses platelet aggregation by causing irreversible inhibition of cyclooxygenase
Indications for acetylsalicylic acid
Inflammatory disorders
Fever
Prophylaxis for myocardial infarction and stroke
Non-opioid analgesic
Therapeutic effect of acetylsalicylic acid
Decreased pain
Decreased inflammation
Decreased incidence of stroke and MI
Adverse effects of acetylsalicylic acid
Heart burn, nausea → take with food or full glass of water
GI bleeds → may cause anemia with chronic occult blood loss
Gastric ulceration, perforation, bleeding, hemorrhage → prophylaxis with a PPI is recommended
Bleeding → discontinue 1-2 weeks prior to surgical procedures
Renal impairment → acute, reversible impairment in renal function
Salicylism → syndrome resulting from high levels of aspirin
Precautions of acetylsalicylic acid
Allergies/ hypersensitivity/ asthma
Bleeding disorders or thrombocytopenia
Use cautiously in renal dysfunction, chronic alcohol abuse, history of GI bleeds or ulcer disease, liver disease
Nursing considerations for acetylsalicylic acid
Monitor for signs and symptoms of bleeding → hypotension, tachycardia, dizziness, weakness, pallor, bruising, bleeding gums, epitaxis, hematuria, melena, labs (CBC)
After procedures and injections → apply pressure to site to prevent bleeding and monitor the site carefully
Take aspirin with food or glass of water
Discontinue at least one week prior to surgery
Monitor renal function → weigh patient, urea and creatinine levels, urine output
Aspirin - prevention of stroke
Thromboxane A2 → stimulates activation of new platelets and increases platelet aggregation
Often stroke result from platelet aggregation at site of endothelial damage
Aspirin prevents platelet adhesion and aggregation → inhibits the formation of thromboxane A2 by platelets
Dose of aspirin for prevention of cardiovascular disease
81mg per day
Treatment of aspirin after ischemic stroke
Initiate within 48 hours of stroke onset
Most common sites for bleeding
Recent wounds
Sites of needle puncture
Sites of invasive procedures/ surgery
Exemplar of thrombolytic
Tissue plasminogen activator (Alteplase)
Tissue Plasminogen Activator (Alteplase) MOA
Binds to fibrin in a blood clot and activates plasminogen, forming plasmin (fibrinolytic enzyme) which breaks down and dissolves the clot
Indications for Tissue Plasminogen Activator (Alteplase)
Acute MI
Ischemic stroke
Pulmonary embolus
Therapeutic effect of Tissue Plasminogen Activator (Alteplase)
Break down clot and restore blood flow through the vessel
Adverse effects for Tissue Plasminogen Activator (Alteplase)
There are two main reasons for bleeding:
1. Plasmin destroys preexisting clots and can promote bleeding at sites that have recently healed
2. Degradation of clotting factors which disrupts the ability for the body to coagulate when trauma or injury does occur
Nursing considerations for Tissue Plasminogen Activator (Alteplase)
Patients are screened carefully admin - ischemic stroke must be confirmed on CT scan
Must be administered within 3-4.5 hrs of symptoms onset - “door to needle” < 60 min
Patient history taken to determine contraindications
Baseline coagulation blood work sent (INR, aPTT, platelets, hgb)
Frequent monitoring of vital signs and EKG monitoring
Glasgow Coma Scale and neurochecks - high risk for intracranial bleeding
Monitor for bleeding - major risk
Hold all anticoagulants and antiplatelets for 24hr
To reduce risk of bleeding → avoid subcut and IM injections, minimize invasive procedures, do not administer with anticoagulants, do not administer with antiplatelets
Absolute contraindications for Tissue Plasminogen Activator (Alteplase)
Previous intracranial bleeding
Known intracranial lesions/ tumours
Active internal bleeding (with the exception of menses)
Suspected aortic dissection
Relative contraindications for Tissue Plasminogen Activator (Alteplase)
Severe uncontrolled hypertension >180/110 mmHg
Current anticoagulant use
Traumatic/ prolonged CPR/ surgery <3 weeks ago
Recent internal bleeding (within 2-4 weeks)
Pregnancy
Active peptic ulcer
TPA and stroke
Only use for ischemic stroke - must be confirmed with CT scan
Must be administered within 4.5 hours of symptom onset
Administered to reestablish blood flow through a blocked artery
Increases risk of intracranial hemorrhage
Drug example of an anticoagulant
Unfractionated heparin
Unfractionated heparin MOA
Enhance activity of antithrombin which is a protein that inactivates clotting factors (thrombin and factor Xa). Without these two clotting factors, there is reduced production of fibrin and clotting is suppressed
Indications for unfractionated heparin
Pulmonary embolism
Deep vein thrombosis
Dialysis and open-heart surgery
Post-operative, spinal cord injury, stroke DVT prophylaxis → to be initiated within 48-72 hrs of ischemic stroke
Acute myocardial infarction
Therapeutic effect of unfractionated heparin
Prevention of new clots
Adverse effects of unfractionated heparin
Bleeding/ hemorrhage → develops in about 10% of patients
Epidural hematoma → can develop in patients with epidural/ spinal anaesthesia
Heparin Induced Thrombocytopenia (HIT) → immune mediated disorder causing reduced platelet count and increase in thrombotic events. Antibodies develop against heparin-platelet complexes
Antidote → Protamine Sulfate
Nursing considerations for unfractionated heparin
Monitor vital signs
Labs → monitor aPTT (activated partial thromboplastin time), should be checked every 4-6 hrs when on a heparin infusion, monitor platelets and hgb
Monitor for signs and symptoms of bleeding → pallor, bruising, bleeding gums, epistaxis, melon, hematuria
Monitor hands and feet for colour, warmth, circulation, movement → signs of clots from heparin induced thrombocytopenia
Drug example of HMG-CoA reductase inhibitor “statins”
Atorvastatin (Lipitor)
HMG-CoA reductase inhibitor “statins” MOA
Lower the rate of cholesterol production
HMG-CoA reductase synthesizes cholesterol → statins block the enzyme which decreases cholesterol production
Liver increases LDL receptors and hepatocytes remove LDL from blood
Indications for HMG-CoA reductase inhibitor “statins”
Hypercholesterolemia
Risk reduction for stroke, myocardial infarction, and angina
Diabetes
Therapeutic effect of HMG-CoA reductase inhibitor “statins”
Lower LDL cholesterol
Elevate HDL cholesterol
Reduce triglycerides
Nursing considerations for HMG-CoA reductase inhibitor “statins”
Check serum lipid levels and triglycerides
Should assess liver function (LFTs)
Administer in evening
Additional info for HMG-CoA reductase inhibitor “statins”
Well tolerated overall, minimal side effects
Teratogenic
Should not have grapefruit juice
