Tacrolimus is an antibiotic

Tacrolimus

What interactions does tacrolimus show?

Please note that the interactions may differ depending on the dosage form of a drug (e.g. tablet, syringe, ointment).

Tacrolimus does not enter the body from the skin. This suggests that when used as an ointment, no interactions with other active ingredients are to be expected. However, it is not possible to ultimately rule out interactions, so tacrolimus should not be used together with erythromycin, itraconazole, ketoconazole or diltiazem as a precaution.

When used as a capsule or infusion solution, the following interactions must be observed:

When combined with other active substances that suppress the immune system (immunologics), there is an increased risk of infections and cancer.

The active ingredient must not be given at the same time as ciclosporin, since kidney damage could occur more frequently. Medical care should be taken when switching from cyclosporine to the drug containing tacrolimus. Treatment with the drug can only be started after checking the concentration of cyclosporine in the blood and the patient's condition. Tacrolimus must not be given as long as there is a high concentration of cyclosporine. In practice, treatment with tacrolimus was started twelve to 24 hours after ciclosporin was discontinued. Because of a possible impairment of the excretion of ciclosporin by tacrolimus, the ciclosporin concentration in the blood must be monitored by a doctor even after the switch.

Tacrolimus is broken down by the enzyme cytochrome P450-3A4. Many other drugs are broken down by this enzyme, so that numerous interactions can arise:

In this way, the following active ingredients can increase the tacrolimus concentration in the blood and thus its side effects: the Parkinson’s drug bromocriptine, the chemotherapy drug dapsone, the ergot alkaloid ergotamine, the hormones gestodene and cortisone, the local anesthetic lidocaine, the calming agent midazolam, the breast cancer drug tamoxifen, the antihypertensive agent verapamil, anti-fungal drugs such as clotrimazole, fluconazole, itraconazole, ketoconazole and miconazole, antibiotics such as clarithromycin and erythromycin, antihypertensive drugs such as diltiazem, nifedipine and nicardipine, anti-HIV drugs such as ricloaveporazole and saccinavirazole, the gastric anti-HIV drugs such as indinavrazol against rejection reactions and the hormone ethinylestradiol.

Active ingredients that improve the function of the enzyme cytochrome P450-3A4 lower the blood concentration of tacrolism and thus reduce its effectiveness. This group includes the tuberculosis drugs isoniazid and rifampicin, the pain reliever metamizole, the anti-epileptic drugs phenytoin, phenobarbital and carbamazepine, and St. John's wort (for depression). In almost all cases, higher tacrolimus doses are required here. High-dose prednisolone or methylprednisolone, as used in acute rejection reactions, can increase or decrease the concentration of tacrolimus in the blood.

Since tacrolimus also inhibits the cytochrome ferment, there are a number of interactions for other active ingredients as well. This inhibits the breakdown of the body's own hormones cortisone and testosterone. In addition, the effectiveness of the pill can be limited. It also increases the blood level of phenytoin. The required dosage of phenytoin is therefore lower.

Fatty foods can delay the absorption of tacrolimus into the blood and thus its effects.

Since tacrolimus is bound to a high degree to proteins in the blood, active ingredients that are also strongly bound to proteins should be avoided. These include anti-coagulant tablets (anticoagulants), oral anti-diabetic drugs and non-steroidal anti-inflammatory drugs.

Other active ingredients, which can also lead to nerve or kidney damage, make tacrolimus more dangerous. These active ingredients include the antibiotics aminoglycosides, gyrase inhibitors, vancomycin, co-trimoxazole, non-steroidal anti-inflammatory drugs and the viral agents ganciclovir and aciclovir.

Increased kidney damage was observed with simultaneous use of the fungus drug amphotericin B and the pain reliever ibuprofen with tacrolimus.

Potassium-rich diet, potassium-containing drugs and potassium-sparing diuretics, together with tacrolimus, can greatly increase the blood potassium level and thus lead to cardiac arrhythmias.

The safety and effectiveness of vaccinations during treatment with tacrolimus are not guaranteed. Live vaccines should be avoided.

Grapefruit juice also affects the enzyme cytochrome and can inhibit the breakdown of tacrolimus.