In overdose, iprindole is much less toxic than most other TCAs and is considered relatively benign. For instance, between 1974 and 1985, only two deaths associated with iprindole were recorded in the United Kingdom, whereas 278 were reported for imipramine, although imipramine is used far more often than iprindole.
On account of these interactions, caution should be used when combining iprindole with other drugs. As an example, when administered with amphetamine or methamphetamine, iprindole increases their brain concentrations and prolongs their terminal half-lives by 2- to 3-fold, strongly augmenting both their physiological effects and neurotoxicity in the process.
The binding affinities of iprindole for various biological targets are presented in the table to the right. It is presumed to act as an inhibitor or antagonist/inverse agonist of all sites. Considering the range of its therapeutic concentrations (e.g., 63–271 nM at 90 mg/day), only the actions of iprindole on the 5-HT2 and histamine receptors might be anticipated to be of possible clinical significance. However, it is unknown whether these actions are in fact responsible for the antidepressant effects of iprindole. The plasma protein binding of iprindole and hence its free percentage and potentially bioactive concentrations do not seem to be known.
Only one study appears to have evaluated the pharmacokinetics of iprindole. A single oral dose of 60 mg iprindole to healthy volunteers has been found to achieve mean peak plasma concentrations of 67.1 ng/mL (236 nmol/L) after 2 to 4 hours. The mean terminal half-life of iprindole was 52.5 hours, which is notably much longer than that of other TCAs like amitriptyline and imipramine. Following chronic treatment with 90 mg/day iprindole for 3 weeks, plasma concentrations of the drug ranged between 18 and 77 ng/mL (63–271 nmol/L). Theoretical steady-state concentrations should be reached by 99% within 15 to 20 days of treatment.
Iprindole has been marketed under the brand name Prondol by Wyeth in the United Kingdom and Ireland for the indication of major depressive disorder, and has also been sold as Galatur and Tertran by Wyeth.
Iprindole was previously available in the United Kingdom and Ireland but seems to no longer be available for medical use in any country.
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