Herein lies a thought with drug interactions when treating side effects like perceived high BP
With any cancer being treated, but article talks about metastic thyroid cancer.
1. Drug-Drug Interactions
Cytochrome P450 enzymes, expressed primarily in the liver, play a primary role in the metabolism of many drugs. Sunitinib, sorafenib, pazopanib, and vandetanib are all metabolized by cytochrome P450 3A4 (CYP3A4). Of the four drugs, sorafenib appears to be the least susceptible to CYP3A4 inducers or inhibitors, although the package labeling warns against concomitant use of CYP3A4 inducers [8]. Concomitant use of CYP3A4 inducers may decrease the plasma concentration of the TKI, resulting in decreased efficacy, while inhibitors may increase the plasma concentration, resulting in toxicity. Itraconazole, a potent inhibitor of CYP3A4, does not appear to affect the metabolism of vandetanib [9]. Table 2 lists the more common, clinically significant drugs metabolized via the CYP3A4 enzyme system.
The medical history should include a thorough review of medications which may affect the metabolism of the TKI. Concomitant drugs which are metabolized via CYP3A4 should be avoided or substituted for another drug. If a CYP3A4 inhibitor drug cannot be eliminated, a dose reduction in the TKI should be considered. Patients should also be monitored for increasing side effects if a CYP3A4 inhibitor is coadministered.
Table 2: Clinically significant CYP3A4 inducers, inhibitors, and substrates.
CYP3A4 inducersCYP3A4 inhibitorsCYP3A4 substrates
DexamethasoneCalcium channel blockers: amiodarone, verapamilStatins: atorvastatin, lovastatin, and simvastatin (not pravastatin) (not rosuvastatin)
Anticonvulsants: phenytoin, carbamazepineAzole antifungals: itraconazole, voriconazole, and ketoconazoleCalcium channel blockers: amlodipine, diltiazem, felodipine, nifedipine, and verapamil
Phenobarbital
RifampinMacrolide antibiotics: erythromycin, and clarithromycin (not azithromycin)
St. John’s wort
HIV antivirals: nonnucleoside reverse transcriptase inhibitors: efavirenz, and nevirapineHIV antivirals: protease inhibitors: indinavir, nelfinavir, and ritonavir
https://www.hindawi.com/journals/jtr/2011/985780/