Compatibility «Sildenafil» and «Amiodarone»

• Interactions Sildenafil with Amiodarone

  • Dangerous interactions
    • ⓘ It is expected that the simultaneous use of sildenafil with powerful inducers of the CYP3A4 isoenzyme will lead to a significant decrease in the concentration of sildenafil in blood plasma.
    • ⓘ The simultaneous use of sildenafil with powerful CYP3A4 inducers (carbamazepine, phenytoin, phenobarbital, St. John's wort preparations, rifampicin) can lead to a significant decrease in the concentration of sildenafil in blood plasma.
    • ⓘ lidocaine (risk of sinus bradycardia and neurological symptoms), tacrolimus (risk of nephrotoxicity), sildenafil (risk of increased side effects), midazolam (risk of psychomotor effects), triazolam, dihydroergotamine, ergotamine, colchicine.
  • Negative interactions
    • ⓘ It is assumed that with simultaneous administration of sildenafil with CYP3A4 inducers (rifampicin, etc.), its plasma concentration will decrease.
    • ⓘ Sildenafil metabolism occurs mainly under the action of cytochrome P450 isoenzymes: CYP3A4 isoenzyme (main pathway) and CYP2C9 isoenzyme (minor pathway), therefore, inhibitors of these isoenzymes can reduce the clearance of sildenafil, and inducers can increase its clearance.
    • ⓘ In a study in healthy volunteers (men), the use of endothelin antagonist bosentan, which is a moderate inducer of CYP3A4, CYP2C9 and possibly CYP2C19 isoenzymes, at steady state (125 mg 2 times a day) led to a decrease in AUC and max'>C_max sildenafil at steady state (80 mg 3 times a day) by 62.6 and 55.4%, respectively.
    • ⓘ The use of ritonavir (500 mg 2 times a day), an HIV protease inhibitor and a powerful CYP3A4 isoenzyme inhibitor in combination with sildenafil (100 mg once) led to an increase in max'>C_max sildenafil by 300% (4 times) and AUC by 1000% (11 times).
    • ⓘ The combined use of saquinavir (1200 mg 3 times a day), an HIV protease inhibitor and CYP3A4 isoenzyme, with sildenafil (100 mg once) leads to an increase in max'>C_max sildenafil by 140% and AUC by 210%.
    • ⓘ The most powerful inhibitors of the CYP3A4 isoenzyme, such as ketoconazole and itraconazole, may have an effect similar to that of ritonavir.
    • ⓘ With a single dose of sildenafil at a dose of 100 mg against the background of therapy with erythromycin, which is a moderate inhibitor of the CYP3A4 isoenzyme, in an equilibrium state (500 mg 2 times a day for 5 days), an increase in the AUC of sildenafil by 182% was revealed (see 'Method of administration and doses').
    • ⓘ Inhibitors of the CYP3A4 isoenzyme such as clarithromycin, telithromycin and nefazodone are suspected to have an effect similar to that of ritonavir.
    • ⓘ CYP3A4 isoenzyme inhibitors such as saquinavir or erythromycin can increase AUC by 7 times.
    • ⓘ In this regard, when used concomitantly with sildenafil, the dose of CYP3A4 isoenzyme inhibitors should be adjusted (see 'Method of administration and doses').
    • ⓘ Cimetidine (800 mg), an inhibitor of cytochrome P450 (a non-specific inhibitor of the CYP3A4 isoenzyme), caused an increase in sildenafil concentrations (50 mg) in the blood plasma of healthy volunteers by 56%.
    • ⓘ Inhibitors of the CYP3A4 isoenzyme and beta-blockers.
    • ⓘ It was found that in patients with PAH, the clearance of sildenafil decreases by approximately 30% when used concomitantly with weak or moderate inhibitors of the CYP3A4 isoenzyme and by 34% when used concomitantly with beta-blockers.
    • ⓘ In studies of interaction with inhibitors of the CYP3A4 isoenzyme, such as saquinavir and erythromycin (excluding the most powerful inhibitors of the CYP3A4 isoenzyme, such as ketoconazole, itraconazole, ritonavir), the AUC of sildenafil increased in this concentration range.
    • ⓘ Sildenafil is a weak inhibitor of cytochrome P450 isoenzymes CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4 (IC₅₀ better 150 microns).
    • ⓘ Sildenafil in a single dose of 100 mg had no effect on the equilibrium pharmacokinetics of the HIV protease inhibitors saquinavir and ritonavir, which are substrates of the CYP3A4 isoenzyme.
  • Positive interactions
    • ⓘ The clearance of sildenafil increases approximately 3-fold when used concomitantly with weak inducers of the CYP3A4 isoenzyme, which corresponds to the effect of bosentan on the clearance of sildenafil in healthy volunteers.
    • ⓘ Grapefruit juice, a weak CYP3A4 inhibitor, may moderately increase plasma concentrations of sildenafil.
  • Unclear interactions
    • ⓘ Inducers of the CYP3A4 isoenzyme.

Decoding the colors of interactions and contraindications

Dangerous	—	a pronounced negative interaction or contraindication.
Negative	—	negative interaction or side effect that may reduce effectiveness.
Positive	—	the interaction can SOMETIMES be used as a positive (often a dose adjustment is needed), or it is an indication of the drug.
No	—	the drugs do NOT interact, which is separately indicated in the instructions.
Unclear	—	the system failed to pre-assess the danger.

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Additional information

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• The use of information about interactions is only possible as an introduction. This information should not be used to adjust therapy without consulting a specialist.
• The article is written: artificial intelligence Kiberis
• Sources: official instructions for medicines and their active substances, as well as inter-group interactions described in medical studies and textbooks.
• Total analyzed: 169,994,378 possible combinations of drugs and their components were found 412,530 interacting combinations.
• Medicine section: Standard evidence-based medicine
• The date of the last update of the interaction database: 2024-12-19

Category - medicine