Caprelsa and Zithromax (Azithromycin Oral Suspension)

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Using vandetanib together with azithromycin can increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening, although it is a relatively rare side effect. You may be more susceptible if you have a heart condition called congenital long QT syndrome, other cardiac diseases, conduction abnormalities, or electrolyte disturbances (for example, magnesium or potassium loss due to severe or prolonged diarrhea or vomiting). Talk to your doctor if you have any questions or concerns. Your doctor may already be aware of the risks, but has determined that this is the best course of treatment for you and has taken appropriate precautions and is monitoring you closely for any potential complications. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or heart palpitations during treatment with these medications, whether together or alone. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

GENERALLY AVOID: Vandetanib can cause concentration-dependent prolongation of the QT interval. Theoretically, coadministration with other agents that can prolong the QT interval may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. In a phase 3 clinical trial where 231 medullary thyroid cancer patients were randomized to receive vandetanib 300 mg once daily, mean change in QTcF (Fridericia-corrected QT interval) from baseline based on the exposure-response relationship was 35 ms for the 300 mg dose. The QTcF increase remained above 30 ms for the duration of the trial (up to 2 years). In addition, 36% of patients experienced greater than 60 ms QTcF increases from baseline and 4.3% had QTcF greater than 500 ms. Vandetanib treatment alone has been associated with reported cases of torsade de pointes, ventricular tachycardia, and sudden death. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia, hypocalcemia). Moreover, the extent of drug-induced QT prolongation is dependent on the particular drug(s) involved and dosage(s) of the drug(s).

MANAGEMENT: Coadministration of vandetanib with other drugs that can prolong the QT interval should generally be avoided. Should treatment with other QT-prolonging drugs be required, the manufacturer recommends more frequent monitoring of the ECG as well as serum potassium, magnesium, and calcium levels. Given vandetanib's half-life of 19 days, ECGs and serum electrolytes should typically be obtained at baseline, at 2 to 4 weeks and 8 to 12 weeks after starting treatment, and every 3 months thereafter. Vandetanib should not be started if baseline QTcF is greater than 450 ms, and treatment should be interrupted if QTcF is greater than 500 ms. Treatment may resume when QTcF returns to less than 450 ms, but at a reduced dosage. In addition, hypokalemia, hypomagnesemia, and/or hypocalcemia must be corrected prior to vandetanib administration. Since diarrhea is a common side effect of vandetanib and may cause electrolyte imbalances, ECG and electrolyte levels should also be monitored more frequently when diarrhea develops. Vandetanib treatment should be stopped in the presence of severe diarrhea. Treatment may resume when diarrhea improves, but at a reduced dosage. Following any dosage reduction, or any interruption of treatment greater than 2 weeks, QT assessment and serum electrolytes should be conducted as described previously. Patients should be advised to seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitation, irregular heart rhythm, shortness of breath, or syncope. Because of the drug's long half-life, adverse reactions including a prolonged QT interval may not resolve quickly, thus appropriate monitoring is necessary.

Caprelsa

Generic Name: vandetanib

Brand name: Caprelsa

Synonyms: n.a.

What is Caprelsa?

Zithromax (Azithromycin Oral Suspension)

Generic Name: azithromycin

Brand name: Zithromax, Zmax, AzaSite, Azithromycin 3 Day Dose Pack, Azithromycin 5 Day Dose Pack, Zithromax Tri-Pak, Zithromax Z-Pak, Zithromax IV

Synonyms: Zithromax

What is Zithromax (Azithromycin Oral Suspension)?