Generality
Dipyridamole is an active ingredient with platelet anti-aggregation activity and is, therefore, used to prevent the formation of blood clots (thrombi).
Given the action that it is able to exercise, dipyridamole belongs to the category of antithrombotics . It can be administered either alone, or in combination with acetylsalicylic acid (another active ingredient with an anti-platelet aggregation action) or oral anticoagulants.
To perform its function as an obstacle to platelet aggregation, dipyridamole is administered orally (tablets in which the active ingredient is present in different concentrations). Dipyridamole administered parenterally (solution for infusion), on the other hand, is used to perform diagnostic tests .
From the chemical point of view, dipyridamole is a pyrimido-pyrimidine derivative.
Examples of Specialties Drugs containing Dipyridamole
- Aggrenox® (dipyridamole in combination with acetylsalicylic acid)
- Corosan®
- Persantin®
Therapeutic indications
When is the use of Dipyridamole indicated?
The use of oral dipyridamole is indicated in all those cases in which it is necessary to prevent the formation of thrombi in order to avoid the onset of cardiovascular events, even fatal, caused by them.
In detail, dipyridamole can be used - alone or in combination with other antiplatelet agents, or in association with oral anticoagulants - in the following cases:
- Prevent the formation of blood clots (thrombi) in patients with mechanical heart valve prostheses ;
- Prevent ischemic stroke and transient ischemic attacks caused by thrombus in patients who have previously experienced similar cardiovascular events.
Dipyridamole parenterally
Injecting dipyridamole is used in adults to perform certain types of tests when it is not possible to perform physical exercise or when it is not possible to perform an exercise test. In detail, dipyridamole is administered intravenously to:
- Perform the imaging examination of myocardial perfusion, in association with a radiopharmaceutical - thallium - in order to observe the heart;
- Evaluate the correct functioning of the coronary arteries by means of the ultrasound examination of the coronaries .
Warnings
Warnings and Precautions for the use of Dipyridamole
In order to avoid the appearance of unpleasant side effects, before starting treatment with dipyridamole, you must inform your doctor if you are in one or more of the following situations:
- You suffer from hypotension (dipyridamole, in fact, can cause peripheral vasodilation causing an excessive lowering of blood pressure);
- If one suffers - or has recently suffered - from diseases affecting the coronaries or the heart;
- If you suffer from myasthenia gravis;
- If you suffer - or have suffered in the past - of biliary tract inflammation and / or gall bladder stones.
Furthermore, if dipyridamole is administered intravenously, it is also important to inform your doctor if:
- One is suffering from chronic obstructive pulmonary disease;
- One is suffering from bronchial asthma;
- You suffer from pulmonary arterial hypertension;
- You are allergic to theophylline or other methylxanthines.
Please note
Since the safe use of dipyridamole in adolescents and children has not been established, the use of the active ingredient in this category of patients is not recommended.
Finally, please note that taking dipyridamole may cause dizziness, therefore caution is advised in performing "dangerous" activities such as driving vehicles and / or using machinery.
Pharmacological Interactions
Interactions of Dipyridamole with Other Drugs
Because of the drug interactions that could occur, before taking dipyridamole, you need to tell your doctor if you are taking - or if you have recently been - drugs, such as:
- Xanthine derivatives, such as theophylline or other methylxanthines ;
- Other antiplatelet agents or oral anticoagulants (although the association between these drugs and dipyridamole can be made, it must take place at well established doses and only under the strict control of the doctor);
- Adenosine (dipyridamole enhances the action);
- Antihypertensive drugs (dipyridamole may accentuate the therapeutic action);
- Cholinesterase inhibitors used in the treatment of myasthenia gravis (dipyridamole can reduce its therapeutic efficacy).
In any case, it is always good to inform your doctor if you are taking - or have recently been taken - drugs or substances of any other type, including non-prescription medicines (SOP), OTC drugs, the herbal and herbal products and homeopathic products.
Dipyridamole for parenteral administration with food and drink
When the dipyridamole must be administered parenterally by infusion, in the previous 24 hours, it is necessary to avoid the intake of foods and / or drinks containing xanthine derivatives, such as coffee, tea, cocoa and some types of carbonated drinks (for example, Coca -There).
Side effects
Side effects
Side Effects Caused by Dipyridamole Intake
Like any other active ingredient, dipyridamole is also capable of causing side effects, although not all patients manifest them, or manifest them equally. In fact, each individual responds to the assumption of the drug in a subjective manner.
Below are listed some of the main side effects that could occur with dipyridamole.
Cardiovascular disorders
Dipyridamole therapy may cause the appearance of:
- Hypotension;
- Hot flashes;
- Tachycardia;
- Angina pectoris.
In addition, parenteral administration of dipyridamole could cause:
- Hypertension;
- bradycardia;
- Myocardial infarction;
- Ventricular fibrillation;
- Cardiac arrest;
- Sinus arrest;
- Atrioventricular block;
- Syncope.
Nervous system disorders
Dipyridamole oral therapy can promote the onset of headaches and dizziness. When the active ingredient is administered by infusion, in addition to what has just been said, it can also cause:
- paresthesia;
- Cerebrovascular events;
- Convulsions.
Gastrointestinal disorders
When taking dipyridamole, they may occur:
- Nausea and / or vomiting;
- Diarrhea;
- Abdominal pains;
- Dyspepsia.
Other side effects
Other side effects that may occur during dipyridamole treatment consist of:
- Allergic reactions, even serious, in sensitive individuals;
- Angioedema;
- Worsening of pre-existing coronary diseases;
- Myalgia;
- bronchospasm;
- Rashes and hives;
- Increased risk of bleeding, in particular, post-procedural and operative (side effect which, however, appears to be extremely rare);
- In case of parenteral administration, reactions at the injection site (for example, edema).
Overdose
If overdoses of oral dipyridamole are taken, symptoms may occur, such as:
- Hot flashes;
- Sweating;
- Restlessness;
- Weakness;
- Dizziness;
- Chest pains (angina);
- Hypotension;
- Tachycardia.
In such a situation, therefore, it is necessary to alert health workers (call 118) or go to the nearest emergency room. Treatment is generally symptomatic and supportive .
As for dipyridamole administered by intravenous infusion, since this operation can only be performed by a specialized doctor, overdose is an extremely rare occurrence.
Action mechanism
How does Dipyridamole work?
Dipyridamole exerts its antiplatelet activity mainly through two mechanisms of action:
- Inhibition of phosphodiesterase type 3 (PDE-3): PDE-3 is the enzyme responsible for the degradation of AMPc (cyclic adenosine monophosphate, molecule with inhibitory action against aggregation and platelet degranulation) in AMP (adenosine monophosphate, a molecule that instead promotes platelet degranulation). With the inhibition of PDE-3, therefore, there is an increase in the levels of AMPc which results in the inhibition of platelet aggregation.
- Inhibition of adenosine uptake by platelets, red blood cells and endothelial cells : by exercising this inhibition, dipyridamole causes an increase in the local concentration of adenosine which - interacting with its type 2 receptors located on platelets (A2 receptors) - occurs - induces an increase in the levels of MPPCs . This last molecule, as we have seen, inhibits platelet degranulation and aggregation.
Method of use and Posology
How to take Dipyridamole
As mentioned, dipyridamole is available in pharmaceutical formulations suitable for oral use and for infusion use .
Dipyridamole orally
Dipyridamole-based tablets should be swallowed whole with the help of a little water. The dose of active ingredient usually administered is 300-450 mg per day, to be taken in divided doses throughout the day. It should be taken on an empty stomach, preferably one hour before meals.
In severe cases, the daily dose can be increased up to a maximum of 600 mg of dipyridamole. However, it is necessary to strictly follow the indications provided by the doctor .
Dipyridamole for infusion
Dipyridamole for infusion can only be administered by a specialized doctor who will determine, case by case, also the dose of active ingredient to be used.
Pregnancy and breastfeeding
Can Dipyridamole be taken during pregnancy and during breastfeeding?
The studies conducted so far have not shown the presence of risks and dangers deriving from the oral intake of dipyridamole during pregnancy. However, as a precautionary measure, its use is not recommended in particular during the first trimester of gestation .
Therefore, the decision to administer dipyridamole or not to pregnant women lies solely with the doctor. A similar discourse on breastfeeding mothers. Clearly, if the need arises to take dipyridamole, this category of patients must necessarily inform the doctor of their pregnancy or breastfeeding condition.
Contraindications
When Dipyridamole should not be used
The use of dipyridamole is contraindicated in the following cases:
- Known hypersensitivity to dipyridamole itself, to the excipients and / or to the other active ingredients - if any - contained in the medicinal product to be used;
- In patients suffering from serious cardiovascular diseases (for example, acute cardiac infarction, unstable angina, decompensated heart failure, basal hypotension, bradycardia, etc.).
Please note
If dipyridamole is associated with other antiplatelet agents (for example, acetylsalicylic acid) or oral anticoagulants, there may be additional contraindications. The same applies to warnings and precautions, side effects and possible drug interactions.
In this case, it is advisable to ask your doctor for information, just as it is advised to read carefully the package insert of the medicine that you must use.
