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Drug Interactions between alectinib and saquinavir

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

saquinavir alectinib

Applies to: saquinavir and alectinib

MONITOR: Coadministration of alectinib with other agents that can slow the heart rate may increase the risk of bradycardia. In clinical trials, 7.5% of patients developed bradycardia during treatment with alectinib. Twenty percent of 221 patients for whom serial electrocardiograms were available had heart rates of less than 50 beats per minute (bpm).

MANAGEMENT: Caution is advised when alectinib is prescribed with other drugs that can cause bradycardia (e.g., beta-blockers; calcium channel blockers; digitalis; dolasetron; flecainide; ivabradine; lacosamide; mefloquine; moricizine; propafenone; quinine; succinylcholine; sunitinib; thalidomide; anticholinesterase or cholinergic agents; protease inhibitors such as atazanavir, lopinavir/ritonavir, and saquinavir/ritonavir). Heart rate and blood pressure should be monitored regularly, and patients should be counseled to seek medical attention if they experience dizziness, lightheadedness, fainting, or irregular heartbeat. Dosage modification of alectinib is not required in cases of asymptomatic bradycardia. However, if symptomatic bradycardia occurs, the manufacturer recommends withholding alectinib until recovery to asymptomatic bradycardia or to a heart rate of >=60 bpm. Evaluate concomitant medications known to cause bradycardia and all antihypertensive medications, then consider dosage adjustments or discontinuation of concomitant medication(s) or alectinib in accordance with the product labeling.

References (1)
  1. (2015) "Product Information. Alecensa (alectinib)." Genentech

Drug and food interactions

Moderate

saquinavir food

Applies to: saquinavir

ADJUST DOSING INTERVAL: Food significantly increases the absorption of saquinavir.

MONITOR: Coadministration with grapefruit juice may increase the plasma concentrations of saquinavir. The primary mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. In eight healthy volunteers, ingestion of 400 mL of grapefruit juice prior to administration of a 600 mg dose of saquinavir mesylate increased the area under the plasma concentration-time curve and oral bioavailability of saquinavir by 50% and 100%, respectively, compared to water; however, the increase is not considered clinically relevant. A high degree of intersubject variability in the grapefruit juice effect was also observed. The extent to which this interaction may occur with the saquinavir free base soft gelatin capsule is unknown. However, the saquinavir soft gelatin capsule formulation is no longer commercially available.

MANAGEMENT: Saquinavir mesylate should be taken with meals or within 2 hours after eating to enhance bioavailability. Patients should be advised to avoid the consumption of large amounts of grapefruit and grapefruit juice during saquinavir therapy unless otherwise directed by their doctor, as the interaction is unreliable and subject to a high degree of interpatient variation.

References (6)
  1. (2001) "Product Information. Invirase (saquinavir)." Roche Laboratories
  2. Kupferschmidt HHT, Fattinger KE, Ha HR, Follath F, Krahenbuhl S (1998) "Grapefruit juice enhances the bioavailability of the HIV protease inhibitor saquinavir in man." Br J Clin Pharmacol, 45, p. 355-9
  3. Bailey DG, Malcolm J, Arnold O, Spence JD (1998) "Grapefruit juice-drug interactions." Br J Clin Pharmacol, 46, p. 101-10
  4. Eagling VA, Profit L, Back DJ (1999) "Inhibition of the CYP3A4-mediated metabolism and P-glycoprotein-mediated transport of the HIV-I protease inhibitor saquinavir by grapefruit juice components." Br J Clin Pharmacol, 48, p. 543-52
  5. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  6. Cerner Multum, Inc. "Australian Product Information."
Moderate

alectinib food

Applies to: alectinib

ADJUST DOSING INTERVAL: Food significantly enhances the oral bioavailability of alectinib and its major active metabolite, M4. According to the manufacturer, a high-fat, high-calorie meal increased the combined systemic exposure (AUC) of alectinib and M4 by 3.1-fold following oral administration of a single 600 mg dose of alectinib.

MANAGEMENT: To ensure maximal oral absorption, alectinib should be administered with food.

References (1)
  1. (2015) "Product Information. Alecensa (alectinib)." Genentech

Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.


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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.