Carbamazepine
Adverse Effect: Carbamazepine toxicity (ataxia, nystagmus, diplopia, headache, vomiting, apnea, seizures, coma) Clinical Management: Monitor serum concentrations of carbamazepine when terfenadine is added or discontinued from therapy. Patients should be followed for any symptoms of carbamazepine toxicity.
Cisapride
Adverse Effect: prolongation of the QTc interval and/or torsades de pointes Clinical Management: Concomitant use of terfenadine and cisapride is not recommended.
Clarithromycin
Adverse Effect: cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Clinical Management: Concomitant use of clarithromycin and terfenadine is contraindicated.
Efavirenz
Adverse Effect: Efavirenz causes inhibition of isoenzyme CYP3A4 Terfenadine is mainly metabolized via CYP3A4 so it leads to lower clearance of Terfenadine resulting in serious adverse events. # Clinical Management: Avoid concomitant use of Terfenadine and Efavirenz.
Erythromycin
Adverse Effect: Cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Clinical Management: Concurrent use of terfenadine and erythromycin is contraindicated.
Fluconazole
Adverse Effect: increased serum concentrations of terfenadine, increased serum concentration of the terfenadine active metabolite, and possible cardiotoxicity (QT interval prolongation, torsades de pointes) Clinical Management: The concurrent use of terfenadine and other azole-type antifungals (e.g. itraconazole and ketoconazole) is contraindicated. Due to similarities between these agents and fluconazole, concomitant use of terfenadine and fluconazole is not recommended.
Fluoxetine
Adverse Effect: cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Clinical Management: With concomitant therapy, consideration should be given to counsel patients on this potential interaction and instruct them to immediately report to their doctor a increased or irregular heart rate.
Frusemide
Hypokalaemia induced by diurectic
Itraconazole
Adverse Effect: cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Clinical Management: The concurrent use of itraconazole and terfenadine is contraindicated.
Ketoconazole
Adverse Effect: cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Clinical Management: Concurrent use of terfenadine and ketoconazole is contraindicated.
Pimozide
Adverse Effect: Increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Clinical Management: Pimozide is contraindicated in individuals with congenital QT syndrome, patients with a history of cardiac arrhythmias, or patients taking other drugs which may prolong the QT interval.
Sertraline
Adverse Effect: cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Clinical Management: Concomitant use of terfenadine and sertraline should be avoided.
Sotalol
Adverse Effect: ventricular arrhythmias Clinical Management: Concurrent use of sotalol and terfenadine is not recommended because both drugs are known to prolong the QT interval.
Sparfloxacin
Adverse Effect: prolongation of the QTc interval and/or torsades de pointes Clinical Management: Sparfloxacin is contraindicated in individuals with known QTc prolongation or in patients being treated concurrently with drugs that are known to increase the QTc interval and/or cause torsades de pointes.
Terbinafine
Adverse Effect: Minor increases in terbinafine serum concentrations Clinical Management: No known alterations in drug therapy are needed during concomitant administration of terfenadine and terbinafine.
Trifluopromazine
Adverse Effect: Increased risk of cardiac arrhythmias # Clinical Management: Avoid the combination if possible |