Pytazen SR 150mg (Dipyridamole)

Pytazen general information

What is Pytazen used for?

Pytazen tablets 150mg are used to prevent blood clot formation (thrombosis) by modifying platelet function in conditions where this would contribute to reducing risk of thromboembolism. If a blood clot forms in a blood vessel and then breaks loose and is carried away in the circulation it can become lodged in another vessel, causing a thromboembolism.  If a clot blocks the blood supply to the heart tissue and it can cause a heart attack (myocardial infarction); or it can travel to the brain and cause a stroke.  Pytazen tablets 150mg are used following surgery to replace a heart valve with a prosthetic heart valve, as there is an increased risk of having a thromboembolic event with artificial heart valves.  Pytazen tablets 150mg are also used in combination with aspirin, another antithrombotic medication that works by a different mechanism, to reduce the rate of having a recurrent heart attack in those who have already has one.   

How does Pytazen work?

Pytazen tablets 150mg contain dipyridamole, a specific and potent inhibitor of platelet aggregation (clumping), which is part of the process that leads to the formation of a blood clot (thrombosis) to plug an injured blood vessel and stop bleeding.  Platelet aggregation is induced by a chemical called adenosine diphosphate (ADP) that is released from platelet granules when they are first activated as well as other from cells.  ADP then undergoes reuptake by the platelets where it interacts with phosphodiesterase, an enzyme that breaks down cAMP and triggers a cascade of intracellular signals that amplify the aggregation process.  Platelet aggregation is also triggered by collagen, which is exposed when a blood vessel becomes damaged.  Dipyridamole in Pytazen tablets 150mg inhibits phosphodiesterase which results in elevated intracellular platelet cAMP levels and blocks platelet aggregation induced by ADP or collagen; it also inhibits reuptake of ADP into platelets^1-3.  Dipyridamole in Pytazen tablets 150mg also stimulates the biosynthesis and release of prostacyclin by the vascular endothelium, which is a single layer of cells that lines all blood vessels.  Prostacyclin is the main prostaglandin produced by endothelial cells and has an important role to play in controlling platelet mediated thrombosis, by inhibiting platelet aggregation among other processes⁴.   The antithrombotic activity of dipyridamole in Pytazen tablets 150mg inhibits the formation of blood clots under conditions where there is risk of thromboembolism and is used for the prevention of thromboembolic complications of cardiovascular disease. 

What does Pytazen contain?

Pytazen tablets contain the active ingredient dipyridamole 150mg, a potent inhibitor of platelet aggregation that is used to prevent thrombus formation.  They also contain acetone, calcium phosphate, monobasic, ethanol, hypromellose, isopropyl alcohol, macrogol 4000, magnesium stearate, methacrylic acid copolymer, purified talc, quinoline yellow, titanium dioxide,

Preventing thrombosis with Pytazen

Pytazen tablets 150mg contain dipyridamole, a specific and potent inhibitor of platelet aggregation (clumping) that is used to prevent blood clot formation (thrombosis) in conditions where there is risk of thromboembolism, which is the formation of a blood clot that breaks loose and is carried away in the circulation to become lodged in another vessel.  Pytazen tablets 150mg are used following surgery to replace a heart valve with a prosthetic heart valve, as there is an increased risk of thromboembolic events with artificial heart valves.  Also in combination with aspirin to reduce the rate of having a recurrent heart attack in those who have already has one.  Platelet aggregation is induced by ADP that triggers a cascade of intracellular signals that amplify the aggregation process; it is also triggered by collagen, which is exposed when a blood vessel becomes damaged.  Dipyridamole in Pytazen tablets 150mg inhibits platelet aggregation induced by ADP or collagen.  It also stimulates the production of prostacyclin by the vascular endothelium (a single layer of cells that lines all blood vessels) that directly inhibits platelet aggregation.  The antithrombotic activity of dipyridamole in Pytazen tablets 150mg inhibits the formation of blood clots under conditions where there is risk of thromboembolism and is used for the prevention of thromboembolic complications of cardiovascular disease.

What are the side effects of Pytazen?

The most commonly reported side effects when taking Pytazen tablets 150mg include, headache, dizziness, diarrhoea, nausea, vomiting, rash, myalgia (muscle pain).

When should Pytazen not be used?

You should not use Pytazen tablets 150mg if you:

• are allergic to dipyridamole or any ingredients in Pytazen
• are pregnant or are breastfeeding
• have severe coronary artery disease including unstable angina, decompensated heart failure and left ventricular outflow obstruction
• have had a recent myocardial infarction (heart attack)
• have myasthenia gravis (muscle weakness)
• have coagulation disorders
• are taking medicines that interact with Pytazen including, adenosine for arrhythmia, cholinesterase inhibitors (for muscle weakness), drugs for high blood pressure

What medications interact with Pytazen?

Several medications interact with Pytazen tablets 150mg and should either not be taken while you are taking Pytazen or only after discussion and instruction from your doctor:

• Drugs that cause a serious reaction with Pytazen: increased hypotensive effect of drugs for high blood pressure with dipyridamole
• Drugs that are affected by Pytazen: adenosine for arrhythmia, cholinesterase inhibitors (for muscle weakness),

How should Pytazen be taken?

You should take your Pytazen tablets 150mg swallowed whole with a glass of water twice daily before meals.  The dose you take and how often depends on what you are being treated for and your doctor’s recommendation.  You should continue to take your Pytazen tablets 150mg for as long as recommended by your doctor.

How long should you take Pytazen?

You should continue to take your Pytazen tablets 150mg for as long as recommended by your doctor.

Missed dose of Pytazen

If you miss a dose of Pytazen tablets 150mg take it as soon as you remember, unless it is time to take the next dose, then skip the missed dose.  Do not take a double dose.

How should Pytazen be stored?

You should store your Pytazen below 25°C in a cool dry place. 

References

1. Gregov D, Jenkins E, Duncan D, Siebert S, Rodgers S, Duncan B, Bochner F, Lloyd J.  Dipyridamole: pharmacokinetics and effects on aspects of platelet function in man Br. J. clin. Pharmac. (1987), 24, 425-434
2. Woulfe D, Yang J, Brass L. ADP and platelets: the end of the beginning.  J Clin Invest 2001 107 12 1503–1505.
3. Gresele P, Momi S, Falcinelli E.  Anti-platelet therapy: phosphodiesterase inhibitors Br J Clin Pharmacol 2011; 72:4 634–646
4. Moncada S, Korbut R. Dipyridamoleand other phosphodiesterase inhibitors act as antithrombotic agents by potentiating endogenous prostacyclin. The Lancet June 1978, 311, 8077,17 1286-1289