Rivaroxaban

Benjamin Clanner-Engelshofen is a freelance writer in the medical department. He studied biochemistry and pharmacy in Munich and Cambridge / Boston (USA) and noticed early on that he particularly enjoyed the interface between medicine and science. That is why he went on to study human medicine.

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The active ingredient rivaroxaban is used to prevent blood clotting. In contrast to also anticoagulant heparin preparations, which are used by injection, for example, rivaroxaban can be taken as a tablet (orally). Since it works differently than the older blood clots phenprocoumon and warfarin, it is also known as the "new oral anticoagulant" (NOAC). Here you can read everything you need to know about rivaroxaban, side effects and use.

This is how rivaroxaban works

Many diseases and conditions can affect the way blood clots. If the coagulability is reduced, it can lead to bleeding or bleeding to death. In contrast, an increased ability to clot can lead to blood clots in the vessels. If these are carried away by the bloodstream into smaller vessels, they can clog them. The tissues and organs to be supplied then receive too little oxygen, which can quickly become life-threatening in important organs such as the brain or heart.

Blood clotting is a very complex process. First, blood platelets (thrombocytes) accumulate in the relevant area in the vessel (e.g. in the area of ​​an injury), so that a first, provisional wound closure is formed. This process usually takes one to four minutes. Even if no vessels are injured, such clots can form in the blood vessel when there is increased blood clotting.

In order to solidify this loose wound closure, the adhesive protein fibrinogen, which occurs in the blood, is now stored together to form long fibrin threads. This activation to "sticky fibrin" from the soluble, non-sticky fibrinogen is brought about by the enzyme thrombin, which in turn has to be activated by other components of the coagulation system.

One of these coagulation factors is factor Xa (“X” is the Roman numeral for ten; “a” stands for “activated”). It can be inhibited by active ingredients such as rivaroxaban, which effectively reduces the ability to clot (measured as a Quick value or INR value). Since these intervene directly in the coagulation process, they are also called direct oral anticoagulants.

Rivaroxaban uptake, breakdown and excretion

After ingestion by mouth, rivaroxaban is quickly and almost completely absorbed into the blood through the intestinal wall. The highest blood concentrations can be detected two to four hours after ingestion.

About two thirds of the active ingredient is broken down in the liver, partly via so-called CYP enzymes, which also break down many other active ingredients. The resulting rivaroxaban metabolic products are excreted about half in the urine and half in the stool. The remaining third of the active ingredient, which is not broken down, leaves the body exclusively with the urine. About five to nine hours after ingestion, half of the active ingredient is usually eliminated. Elimination may take longer in older patients.

When is rivaroxaban used?

Doctors prescribe the active substance rivaroxaban to treat or prevent blood clots (thromboembolism). Rivaroxaban is used in higher doses in the following cases:

• if you have had blood clots in the deep veins such as the legs or arms (phlebothrombosis)
• if you have had a pulmonary embolism (blood clot blocking the blood vessels in the lungs)
• preventive for certain forms of atrial fibrillation, a rhythm disturbance of the heart, especially if those affected have other risk factors for blood clots (e.g. high blood pressure, heart failure, old age, diabetes mellitus, secondary diseases of "vascular calcification" (arteriosclerosis) such as coronary artery disease or PAD)

In these cases, the intake is usually long-term to lifelong. In addition, doctors can prescribe a lower dose of rivaroxaban to prevent blood clots after hip or knee replacement operations (thrombosis prophylaxis).

This is how rivaroxaban is used

The anticoagulant rivaroxaban is taken in the form of tablets. Depending on the therapeutic application, it is taken once or twice a day with a meal, with doses of five to twenty milligrams of rivaroxaban per day being common. The doctor may combine the active ingredient with other anticoagulants, such as clopidogrel, ticlopidine or ASA (acetylsalicylic acid). Under certain circumstances, this can increase the anticoagulant effect or avoid the occurrence of side effects.

What are the side effects of rivaroxaban?

One in 10 to 1 in 100 people will experience the following rivaroxaban side effects:

• dizziness
• Conjunctivitis and eye bleeding
• bruises
• Coughing up blood
• Bleeding in the gastrointestinal tract
• nausea
• constipation
• Itching, reddening and bleeding of the skin
• Pain in arms and legs
• Water retention

One in hundred to one thousand patients experience side effects such as rapid heartbeat, dry mouth, cerebral haemorrhage, allergic reactions, liver dysfunction, bloody joint effusions and an increase in enzyme and fat levels in the blood.

What should be considered when taking rivaroxaban?

As with other anticoagulants, special attention should be paid to signs and symptoms of bleeding when taking rivaroxaban. If there are signs of heavy bleeding, the intake should be interrupted.

The active substance rivaroxaban is broken down by CYP enzymes in the liver. These enzymes also ensure that other drugs are broken down. Concomitant use of such drugs can affect the breakdown of rivaroxaban. This can increase the effectiveness of the anticoagulant, which increases the risk of bleeding. Examples of such drugs are certain agents against fungal infections (ketoconazole, itraconazole, voriconazole), ritonavir (active ingredient against HIV) and certain antibiotics (clarithromycin, erythromycin).

Conversely, when taken at the same time, other drugs can accelerate the breakdown of rivaroxaban and thus reduce its anticoagulant effect. These include, for example, certain agents for epilepsy (phenytoin, carbamazepine, phenobarbital), the antibiotic rifampicin and the herbal antidepressant St. John's wort.

In general, the following therefore applies: Always discuss the simultaneous use of rivaroxaban and other medications with your doctor or pharmacist beforehand.

If you have severe kidney problems, the blood levels of rivaroxaban may increase.

Since no studies are available on the use in children and adolescents under 18 years of age or in pregnant and breastfeeding women, rivaroxaban should not be used in these groups of people.

How to get rivaroxaban medication

The anticoagulant rivaroxaban requires a prescription in all doses and can only be purchased from a pharmacy following a doctor's prescription.

How long has rivaroxaban been known?

Rivaroxaban was launched in Germany in 2008 by the pharmaceutical company Bayer AG in cooperation with Janssen Pharmaceutica. As the first active ingredient to influence the coagulation factor Xa, rivaroxaban is an innovative drug with high therapeutic relevance, which means that the therapy costs are comparatively high as long as patent protection is still in place.

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