Phenprocoumon is closely related to warfarin and is an anticoagulant drug used to thin the blood, or stop it from clotting. It is derived from coumarin and works by blocking the action of vitamin K, which is an essential ingredient in the body's clotting process. A number of different drugs containing phenprocoumon are available in some countries of the world. They are known by different trade names, according to manufacturer.
The coagulation cascade of the body is complex and involves many proteins and chemicals. Vitamin K plays a vital role in the formation of various clotting factors, which are essential for coagulation to occur. Phenprocoumon acts as a vitamin K antagonist; that is, it stops vitamin K action, thus preventing formation of those clotting factors and preventing coagulation.
There are a number of situations in which phenprocoumon may be given. In most countries it is available by prescription only and requires careful titration in order to reach the ideal anticoagulant dose. This may differ significantly from person to person and requires close monitoring, especially initially, but also throughout therapy.
Treatment may be prescribed to a patient who has had a clot, either a deep vein thrombosis (DVT) or pulmonary thrombosis, post myocardial infarction or heart attack, as well as for prevention of stroke in patients with atrial fibrillation. The dose and duration may differ according to the clinical indication and the patient's response. The prescribed dose should never be exceeded.
A number of drugs may affect phenprocoumon levels and result in the blood being too thick or too thin. Any concomitant drugs, including complementary therapies, homeopathic medications and over-the-counter drugs should be discussed with the prescribing doctor. A change in dose or discontinuation of a drug may also affect phenprocoumon, and the patient's clotting should be monitored in any of these scenarios. Some drugs, such as those that can also cause anti-coagulation, are contraindicated in combination with phenprocoumon.
As with any drug, phenprocoumon may cause adverse effects. Hepatotoxicity, bleeding and bone loss after chronic use have been reported. Should any untoward effect be experienced, immediate medical attention should be sought. Pregnancy, desired pregnancy and lactation should be discussed with the prescribing doctor before considering initiation of therapy. In overdose phenprocoumon may be fatal, so it must be kept out of reach of children.
Duration of phenprocoumon treatment depends on the condition being treated and the severity thereof. In some cases anticoagulation therapy is lifelong, whereas for others therapy may be stopped after some months. Treatment should never be stopped without seeking medical advice first.
