| Rasilez has no known clinically relevant interactions with medicinal products commonly used to treat hypertension or diabetes.Compounds that have been investigated in clinical pharmacokinetic studies include acenocoumarol, atenolol, celecoxib, pioglitazone, allopurinol, isosorbide-5-mononitrate, ramipril and hydrochlorothiazide. No interactions have been identified.Co-administration of aliskiren with either valsartan ( 28%), metformin ( 28%), amlodipine (↑29%) or cimetidine (↑19%) resulted in between 20% and 30% change in Cmax or AUC of Rasilez. When administered with atorvastatin, steady-state Rasilez AUC and Cmax increased by 50%. Co-administration of Rasilez had no significant impact on atorvastatin, valsartan, metformin or amlodipine pharmacokinetics. As a result no dose adjustment for Rasilez or these co-administered medicinal products is necessary.Digoxin and verapamil bioavailability may be slightly decreased by Rasilez.Preliminary data suggest that irbesartan may decrease Rasilez AUC and Cmax.In experimental animals, it has been shown that P-gp is a major determinant of Rasilez bioavailability. Inducers of P-gp (St. John's wort, rifampicin) might therefore decrease the bioavailability of Rasilez.CYP450 interactions Aliskiren does not inhibit the CYP450 isoenzymes (CYP1A2, 2C8, 2C9, 2C19, 2D6, 2E1 and 3A). Aliskiren does not induce CYP3A4. Therefore aliskiren is not expected to affect the systemic exposure of substances that inhibit, induce or are metabolised by these enzymes. Aliskiren is metabolised minimally by the cytochrome P450 enzymes. Hence, interactions due to inhibition or induction of CYP450 isoenzymes are not expected. However, CYP3A4 inhibitors often also affect P-gp. Increased aliskiren exposure during co-administration of CYP3A4 inhibitors that also inhibit P-gp can therefore be expected (see P-glycoprotein interactions below).P-glycoprotein interactions MDR1/Mdr1a/1b (P-gp) was found to be the major efflux system involved in intestinal absorption and biliary excretion of aliskiren in preclinical studies. Rifampicin, which is an inducer of P-gp, reduced aliskiren bioavailability by approximately 50% in a clinical study. Other inducers of P-gp (St. John's wort) might decrease the bioavailability of Rasilez. Although this has not been investigated for aliskiren, it is known that P-gp also controls tissue uptake of a variety of substrates and P-gp inhibitors can increase the tissue-to-plasma concentration ratios. Therefore, P-gp inhibitors may increase tissue levels more than plasma levels. The potential for drug interactions at the P-gp site will likely depend on the degree of inhibition of this transporter.P-gp potent inhibitors A single dose drug interaction study in healthy subjects has shown that ciclosporin (200 and 600 mg) increases Cmax of aliskiren 75 mg approximately 2.5-fold and AUC approximately 5-fold. The increase may be higher with higher aliskiren doses. In healthy subjects, itraconazole (100 mg) increases AUC and Cmax of aliskiren (150 mg) by 6.5-fold and 5.8-fold, respectively. Therefore, concomitant use of aliskiren and P-gp potent inhibitors is contraindicated (see section 4.3).Moderate P-gp inhibitors Co-administration of ketoconazole (200 mg) or verapamil (240 mg) with aliskiren (300 mg) resulted in a 76% or 97% increase in aliskiren AUC, respectively. The change in plasma levels of aliskiren in the presence of ketoconazole or verapamil is expected to be within the range that would be achieved if the dose of aliskiren were doubled; aliskiren doses of up to 600 mg, or twice the highest recommended therapeutic dose, have been found to be well tolerated in controlled clinical trials. Preclinical studies indicate that aliskiren and ketoconazole co-administration enhances aliskiren gastrointestinal absorption and decreases biliary excretion. Therefore, caution should be exercised when aliskiren is administered with ketoconazole, verapamil or other moderate P-gp inhibitors (clarithromycin, telithromycin, erythromycin, amiodarone).P-gp substrates or weak inhibitors No relevant interactions with atenolol, digoxin, amlodipine or cimetidine have been observed. When administered with atorvastatin (80 mg), steady-state aliskiren (300 mg) AUC and Cmax increased by 50%.Organic anion transporting polypeptide (OATP) inhibitors Preclinical studies indicate that aliskiren might be a substrate of organic anion transporting polypeptides. Therefore, the potential exists for interactions between OATP inhibitors and aliskiren when administered concomitantly (see interaction with Grapefruit juice).Furosemide When aliskiren was co-administered with furosemide, the AUC and Cmax of furosemide were reduced by 28% and 49%, respectively. It is therefore recommended that the effects be monitored when initiating and adjusting furosemide therapy to avoid possible under-utilisation in clinical situations of volume overload.Non-steroidal anti-inflammatory drugs (NSAIDs) As with other agents acting on the renin-angiotensin system, NSAIDs may reduce the anti-hypertensive effect of aliskiren. In some patients with compromised renal function (dehydrated patients or elderly patients) aliskiren given concomitantly with NSAIDs may result in further deterioration of renal function, including possible acute renal failure, which is usually reversible. Therefore the combination of aliskiren with an NSAID requires caution, especially in elderly patients.Potassium and potassium-sparing diuretics Based on experience with the use of other substances that affect the renin-angiotensin system, concomitant use of potassium-sparing diuretics, potassium supplements, salt substitutes containing potassium or other substances that may increase serum potassium levels (e.g. heparin) may lead to increases in serum potassium. If co-medication is considered necessary, caution is advisable.Grapefruit juice Administration of grapefruit juice with aliskiren resulted in a decrease in AUC and Cmax of aliskiren. Co-administration with aliskiren 150 mg resulted in a 61% decrease in aliskiren AUC and co-administration with aliskiren 300 mg resulted in a 38% decrease in aliskiren AUC. This decrease is likely due to an inhibition of organic anion transporting polypeptide-mediated uptake of aliskiren by grapefruit juice in the gastrointestinal tract. Therefore, because of the risk of therapeutic failure, grapefruit juice should not be taken together with Rasilez.Warfarin The effects of Rasilez on warfarin pharmacokinetics have not been evaluated.Food intake Meals with a high fat content have been shown to reduce the absorption of Rasilez substantially. | |