Dipyridamole
Mechanism of action:
Inhibits adenosine deaminase and phosphodiesterase, preventing the degradation of cAMP. This reduces the production of thromboxane A2 and platelet aggregation and activation.
Indications:
- Ischemic stroke and TIA
- Adjunct to warfarin for prophylaxis of thromboembolism with prosthetic heart valves.
- Adjunct to Thallium Myocardial Perfusion Imaging (Off-label)
- Prevention of MI recurrence (in combo with aspirin)
| Dipyridamole |
| Dosage Forms & Strengths: injectable solution – 5mg/mL Tablet – 25mg, 50mg, 75mg |
| Administration and handling: The recommended oral dose is 100 mg q.i.d., one hour before meals. The maximum daily dose is 600 mg. IV: The dose of intravenous Dipyridamole for injection used as an adjunct to myocardial perfusion imaging should be adjusted according to the weight of the patient. Immediately prior to infusion, Dipyridamole for injection IV should be diluted at least 1:2 with Dextrose Injection, USP 5%. The recommended dose is 0.142 mg/kg/min., infused over 4 minutes. A total dose of greater than 60 mg is not recommended for use in any patient. The imaging agent should be injected within 5 minutes following the 4-minute infusion of Dipyridamole for injection. |
| Thromboembolism Prophylaxis Post-Cardiac Valve Replacement – 75-100 mg PO q6hr as adjunct to warfarin |
| Adjunct to Thallium Myocardial Perfusion Imaging (Off-label): Adjusted according to body weight; recommended 0.142 mg/kg/min IV infusion over 4 minutes; not to exceed 60 mg |
| Prevention of MI recurrence (in combo with aspirin): No benefit over aspirin alone |
| Pediatric : Off-label Use : 3-6 mg/kg/day PO divided q6-8hr |
Cautions and Contraindications:
- Hypersensitivity
- Used with caution in patients with severe coronary artery disease (e.g., unstable angina or recently sustained myocardial infarction)
- Should be used with caution in patients with hypotension since it can produce peripheral vasodilation.
Side-Effects:
- Chest pain
- GI disturbance
- Worsening coronary heart disease
- Bleeding
- Angina exacerbation
- Abnormal ECG
- Headache Dizziness
Metabolism and Half-Life:
Plasma t ½ is 9-12h: metabolized by liver and excreted through faeces.
Nursing considerations:
- Be alert for signs of transient cerebral ischemia, including sudden weakness/numbness on one side of the body, slurred speech, loss of vision, dizziness, and loss of balance and coordination. Report these signs to the physician immediately.
- Watch for symptoms of bronchospasm (wheezing, coughing, tightness in chest), especially after IV administration. Perform pulmonary function tests to quantify suspected changes in ventilation and respiration.
- Assess heart rate, ECG, and heart sounds, especially during exercise. Report any rhythm disturbances or symptoms of increased arrhythmias, including palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.
- Assess blood pressure periodically and compare to normal values. Report low blood pressure(hypotension), especially if patient experiences dizziness or syncope.
- Assess dizziness that might affect gait, balance, and other functional activities. Report balance problems and functional limitations to the physician and caution the patient and family/caregivers to guard against falls and trauma.
Interventions:
- Because of the risk of arrhythmias and abnormal BP responses, use caution during aerobic exercise and endurance conditioning.
- Assess exercise tolerance frequently (BP, heart rate, fatigue levels), and terminate exercise immediately if any untoward responses occur.
Patient/Client-Related Instruction:
Remind patients to take medication as directed to reduce the risk of thromboembolism or graft occlusion even if they are asymptomatic.
Counsel patients about additional interventions to help reduce the risk of heart disease, including regular exercise, weight loss, sodium restriction, stress reduction, moderation of alcohol consumption, and smoking cessation.
Drug Interactions:
- Enhances cardiovascular effects of adenosine.
- Caution is given in combination of other antiplatelets, anticoagulants or fibrinolytics due to risk of bleeding
Important Points:
- Used in combination with anticoagulation in patients with prosthetic heart valves, and low dose aspirin in patients with ischemic stroke/TIA.
- Only the modified release the formulation is licensed for these indications.
REFERENCES
- Robert Kizior, Keith Hodgson, Saunders Nursing Drug handbook,1st edition 2024, Elsevier Publications. ISBN-9780443116070
- McGraw Hill- Drug Handbook, Seventh Edition, 2013, McGraw Hill Education Publications,9780071799430.
- April Hazard, Cynthia Sanoski, Davi’s Drug Guide for Nurses -Sixteenth Edition 2019, FA Davis Company Publications,9780803669451.
- Jones and Bartlet, Pharmacology for Nurses, Second Edition, 2020, Jones and Bartlet Learning Publications, ISBN 9781284141986.
- Nursebro.com, Search – Nursebro
Stories are the threads that bind us; through them, we understand each other, grow, and heal.
JOHN NOORD
Connect with “Nurses Lab Editorial Team”
I hope you found this information helpful. Do you have any questions or comments? Kindly write in comments section. Subscribe the Blog with your email so you can stay updated on upcoming events and the latest articles.
