Interactions with Tacrolimus

Tacrolimus is almost completely metabolized in the liver by an enzyme (CYP34A) after absorption into the body. Since many other drugs are metabolized by the same enzyme, simultaneous intake may lead to interactions with the risk of an increased or decreased effect. If tacrolism is used after a transplant, there is a risk of rejection of the transplant. Frequent interactions occur in combination with St. John’s wort, carbamazepine, barbiturates, amiodarone, cimetidine and some antibiotics. The simultaneous intake of grapefruit juice can also have considerable effects on the effective level of tacrolimus.

Tacrolimus and alcohol – is it compatible?

In case of known hypersensitivity or allergic reactions against Tacrolimus, the intake should be avoided and instead another immunosuppressive agent should be taken. Also incompatibilities against macrolide antibiotics (e.g. erythromycin, clarithromycin) can lead to hypersensitivity reactions because of the similar structure of Tacrolimus. It has to be considered that some preparations contain lactose. In case of carbohydrate metabolic disorders (e.g. galactose intolerance, lactose intolerance) the possible effects should therefore be discussed with the treating physician before taking Tacrolimus.

Dosage of Tacrolimus

In the systemic application Tacrolimus is usually administered in form of tablets – an intravenous application is however also possible in exceptional cases. Depending on the half-life, a distinction is made between retarded and non-retarded capsules. Retarded capsules are taken once a day (in the morning), while non-retarded capsules are taken twice a day (in the morning and evening).

The exact setting of the dose depends on body weight and disease and is determined by the treating physician. In case of topical application in the form of an ointment, it is applied 1-2 times a day until the symptoms disappear. The application can be continued until one week after the symptoms have subsided.

Tacrolimus Mirrors

The medicinal use of Tacrolimus is subject to a narrow therapeutic range. This means that even slightly increased levels of Tacrolimus in the blood can lead to very serious side effects and slightly decreased levels can lead to a lack of the desired effect. The adjustment of the effective level should therefore be done by the treating physician and should be monitored regularly.