Drug Interactions between Etrafon Forte and ziprasidone

CONTRAINDICATED: Ziprasidone can cause dose-related 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 placebo-controlled trials in adults, oral ziprasidone increased the QTc interval by approximately 10 msec at the highest recommended daily dosage of 160 mg compared to placebo. In a study comparing the QT prolonging effect of several antipsychotic drugs at the maximum plasma concentration following administration alone in patient volunteers, the mean increase in QTc (QT interval corrected for heart rate) from baseline for ziprasidone ranged from approximately 9 to 14 msec greater than for four of the comparator drugs (haloperidol, olanzapine, quetiapine, and risperidone), but was approximately 14 msec less than the prolongation observed for thioridazine. In another study evaluating the QT prolonging effect of intramuscular ziprasidone versus intramuscular haloperidol (control) at the maximum plasma concentration following administration in patient volunteers, the mean increase in QTc from baseline for ziprasidone (20 mg and 30 mg doses given 4 hours apart) was 4.6 msec after the first injection and 12.8 msec after the second injection, which at 30 mg is 1.5 times the highest recommended dose. The mean increase in QTc from baseline for haloperidol (7.5 mg and 10 mg doses given 4 hours apart) was 6.0 msec following the first injection and 14.7 msec following the second injection. No patients had a QTc interval exceeding 500 msec. 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). In addition, 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 ziprasidone with other drugs that can prolong the QT interval is considered contraindicated.

Switch to consumer interaction data

CONTRAINDICATED: Ziprasidone can cause dose-related 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 placebo-controlled trials in adults, oral ziprasidone increased the QTc interval by approximately 10 msec at the highest recommended daily dosage of 160 mg compared to placebo. In a study comparing the QT prolonging effect of several antipsychotic drugs at the maximum plasma concentration following administration alone in patient volunteers, the mean increase in QTc (QT interval corrected for heart rate) from baseline for ziprasidone ranged from approximately 9 to 14 msec greater than for four of the comparator drugs (haloperidol, olanzapine, quetiapine, and risperidone), but was approximately 14 msec less than the prolongation observed for thioridazine. In another study evaluating the QT prolonging effect of intramuscular ziprasidone versus intramuscular haloperidol (control) at the maximum plasma concentration following administration in patient volunteers, the mean increase in QTc from baseline for ziprasidone (20 mg and 30 mg doses given 4 hours apart) was 4.6 msec after the first injection and 12.8 msec after the second injection, which at 30 mg is 1.5 times the highest recommended dose. The mean increase in QTc from baseline for haloperidol (7.5 mg and 10 mg doses given 4 hours apart) was 6.0 msec following the first injection and 14.7 msec following the second injection. No patients had a QTc interval exceeding 500 msec. 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). In addition, 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 ziprasidone with other drugs that can prolong the QT interval is considered contraindicated.

Switch to consumer interaction data

MONITOR: Coadministration of a phenothiazine with a tricyclic antidepressant (TCA) may result in elevated plasma concentrations of one or both drugs as well as additive adverse effects. Most phenothiazines and TCAs have been found to undergo metabolism by CYP450 2D6, thus competitive inhibition of the enzyme may occur when more than one of these agents are administered. Although these drugs have been used together clinically, the possibility of increased risk of serious adverse effects such as central nervous system depression, tardive dyskinesia, hypotension, and prolongation of the QT interval should be considered, as many of these agents alone can and have produced these effects. In addition, excessive anticholinergic effects may occur in combination use, which can result in paralytic ileus, hyperthermia, heat stroke, and the anticholinergic intoxication syndrome. Peripheral symptoms of anticholinergic intoxication commonly include mydriasis, blurred vision, flushed face, fever, dry skin and mucous membranes, tachycardia, urinary retention, and constipation. Central symptoms may include memory loss, disorientation, incoherence, hallucinations, psychosis, delirium, hyperactivity, twitching or jerking movements, stereotypy, and seizures.

MANAGEMENT: Concurrent use of phenothiazines and TCAs should be approached with caution, particularly in the elderly and those with underlying organic brain disease, who tend to be more sensitive to the central anticholinergic effects of these drugs and in whom toxicity symptoms may be easily overlooked. Patients should be advised to notify their physician promptly if they experience potential symptoms of anticholinergic intoxication (e.g., abdominal pain, fever, heat intolerance, blurred vision, confusion, hallucinations) or cardiovascular toxicity (e.g., dizziness, palpitations, arrhythmias, syncope). Ambulatory patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them. A dosage reduction in one or both drugs may be necessary if excessive adverse effects develop.

Switch to consumer interaction data