Dipyridamole

Dipyridamole (Dipyridamole) is a drug that is used for a variety of purposes, including the prevention of thrombosis and embolism. It has several pharmacological actions, including inhibiting platelet aggregation, dilating blood vessels and increasing blood flow.

Dipyridamole is often used in combination with other medicines, such as acetylsalicylic acid (aspirin), to prevent thrombosis after heart surgery or to prevent strokes in patients with a history of circulatory problems.

Also, dipyridamole is sometimes used in the diagnosis of cardiovascular disease, such as in the stress test with myocardial perfusion scintigraphy.

It is important to use dipyridamole only as prescribed by your doctor, as it may have side effects and may interact with other medications.

Indications Dipyridamole

1. Prevention of thrombosis and embolism: Dipyridamole may be prescribed to prevent blood clots and embolisms. This is especially important for people at high risk of thrombosis, such as patients with a history of stroke or heart attack.
2. Stroke prevention: The drug may be used to prevent stroke in people with a history of mini-strokes or transient ischemic attack (TIA).
3. Diagnosis of baseline coronary arterial disease: In some cases, dipyridamole is used in combination with other techniques such as myocardial perfusion scintigraphy or coronary angiography, to evaluate the coronary circulation and identify baseline coronary arterial disease.
4. The drug can be used to improve blood circulation in the veins, which may be useful in the treatment of some venous diseases.

Release form

1. Tablets: Dipyridamole is often available as oral tablets. Tablets may have different dosages depending on the medical purpose.
2. Injectable solution: Dipyridamole may be presented as a solution for injection. This form of release is often used in medical procedures such as angiography or other methods of diagnosing vascular disease.
3. Capsules: Some manufacturers may produce dipyridamole in capsule form, which are also intended for oral administration. This can be a convenient form for patients, especially if they need to take the medication for a long period of time.
4. Combination medicines: Dipyridamole can also be included in combination medicines. For example, it may be part of medicines used to diagnose a stress test using radioisotopes.

Pharmacodynamics

1. Phosphodiesterase inhibition: Dipyridamole is a phosphodiesterase inhibitor, which means that it blocks the enzyme responsible for the breakdown of cyclic adenosine monophosphate (cAMP). An increase in the level of CAMP leads to relaxation of vascular smooth muscles and an increase in their diameter, which helps to increase blood flow to the tissues and improve blood supply to the heart and brain.
2. Increase in adenosine activity: Dipyridamole also stimulates the activity of adenosine, which is a vasodilator and plays an important role in the regulation of blood flow. This promotes vasodilation and improves tissue perfusion.
3. Increase tissue thromboplastin levels: Dipyridamole helps increase tissue thromboplastin levels, which may improve blood clotting and prevent blood clots.
4. Improvement of microcirculation: Dipyridamole may also improve microcirculation in tissues due to its vasodilating action, which promotes better blood supply to cells and organs.

Pharmacokinetics

1. Absorption: Dipyridamole is usually administered orally. After oral administration, it is rapidly and completely absorbed from the gastrointestinal tract.
2. Distribution: Dipyridamole has high affinity to blood plasma proteins and is widely distributed throughout the body tissues. It can penetrate the blood-brain barrier and the placenta.
3. Metabolism: Dipyridamole undergoes metabolic processes in the liver. The main metabolites include glucuronides and sulfates.
4. Excretion: The main route of excretion of dipyridamole and its metabolites is renal excretion. Part of the drug is also excreted through the intestine with bile.
5. Half-life: Half-life of dipyridamole from the body is about 30-60 minutes. In elderly patients this time may be prolonged due to decreased renal function.
6. Pharmacokinetics in special cases: In patients with impaired hepatic or renal function, the pharmacokinetics of dipyridamole may be altered, requiring cautious prescribing and dosage monitoring.

Dosing and administration

1. Prevention and treatment of coronary heart disease:

   • The usual starting dose is 25 mg of dipyridamole taken 4 times daily for the first 2-3 days of treatment.
   • Further, the dose can be increased to 75-100 mg per day, divided into several doses.
   • The maximum daily dose is usually 400 mg, but may be adjusted according to individual patient needs and physician recommendations.

2. Prevention of thrombosis after cardiac surgery:

   • The dosage of dipyridamole may vary depending on the nature of the surgery and the doctor's recommendations. It is usually taken 75-100 mg 3-4 times a day.

3. Cerebral ischemia:

   • For the treatment of cerebral ischemia, 75-100 mg of dipyridamole is usually taken 3-4 times daily.

4. Prevention and treatment of recurrent stroke:

   • To prevent recurrent stroke, 75-100 mg of dipyridamole is usually taken 3-4 times daily.

Use Dipyridamole during pregnancy

The use of dipyridamole during pregnancy requires special caution and should be prescribed only in strict medical indications. There are currently limited data on the safety of dipyridamole during pregnancy.

Although animal studies have shown no teratogenic effects (i.e. Ability to cause birth defects) of dipyridamole, data on its safety during pregnancy in humans are limited. In addition, because dipyridamole may affect blood clotting and bleeding, its use during pregnancy may be associated with a risk of increased bleeding in both mother and fetus.

Contraindications

1. Hypersensitivity or allergic reaction to dipyridamole or other ingredients of the drug.
2. Serious heart rhythm disturbances such as tachycardia or atrial fibrillation, especially if the arrhythmias are not controlled.
3. Active stomach or intestinal ulcers.
4. Severe arterial hypotonicity.
5. Serious circulatory disorders such as hemorrhagic stroke.
6. Last period of pregnancy due to possible effects on fetal development.
7. Time of breastfeeding, as it is not known whether dipyridamole is excreted with breast milk.
8. Caution should be exercised when using dipyridamole in patients with moderate to severe hepatic or renal impairment.

Side effects Dipyridamole

1. Dizziness and headache: These symptoms can be quite common when taking dipyridamole.
2. Feeling hot: Some patients may experience a sudden feeling of heat or redness of the skin.
3. Tachycardia: Increased heart rate may be an observed side effect.
4. Swelling: In some cases, patients may experience swelling, especially in the leg area.
5. Hypotension: Dipyridamole may cause a decrease in blood pressure in some patients.
6. Nausea and vomiting: Some people may experience stomach discomfort, including nausea and vomiting.
7. Abdominal pain: Some patients may experience pain or discomfort in the abdominal area.
8. Allergic reactions: In rare cases, allergic reactions such as itching, skin rash or anaphylactic shock may occur.
9. Hematologic changes: Dipyridamole may cause changes in the blood such as thrombocytopenia (decreased platelet count).
10. Dizziness and drowsiness: Some patients may experience dizziness or drowsiness while taking dipyridamole.

Overdose

1. Cardiovascular complications: An overdose of dipyridamole can cause a severe drop in blood pressure, which can lead to heart attack, arrhythmias, or shock.
2. Gastrointestinal symptoms: This may include nausea, vomiting, abdominal pain, and diarrhea.
3. Neurological symptoms: Headache, dizziness, weakness, drowsiness, seizures and even coma may occur.
4. Other symptoms: Allergic reactions, breathing problems, and other systemic manifestations may also occur.

In case of suspected overdose of dipyridamole, immediate medical attention should be sought. Treatment of overdose usually includes measures to maintain vital body functions, such as maintaining adequate blood circulation and respiration, and symptomatic treatment. Methods of cleansing the body of excess drug, such as gastric lavage or taking activated charcoal, may be required.

Interactions with other drugs

1. Anticoagulants (blood thinners): Dipyridamole may increase the effect of anticoagulants such as warfarin or heparin, increasing the risk of bleeding. Close monitoring of blood clotting may be required with concomitant use of these drugs.
2. Blood pressure-lowering drugs: Dipyridamole may increase the hypotensive effect of blood pressure-lowering drugs, such as antihypertensives, which may lead to a dangerous drop in blood pressure.
3. Adenosine: Dipyridamole may increase the effects of adenosine, which may cause more severe side effects such as dizziness, fainting, or palpitations.
4. Methylxanthines: Dipyridamole may reduce the efficacy of methylxanthines such as theophylline or aminphylline, which may lead to a reduction in their bronchodilator effect.
5. Antiepileptic drugs: Dipyridamole may reduce the effectiveness of antiepileptic drugs such as carbamazepine or phenytoin.