Routes ofadministration By mouth Metabolism | ATC code N06AA13 (WHO) Biological half-life 52.5 hours Molar mass 284.439 g/mol | |
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Legal status In general: ℞ (Prescription only) | ||
Iprindole (Prondol, Galatur, Tertran), formerly known as pramindole, is a tricyclic antidepressant (TCA) used in Europe for the treatment of depression. It was introduced by Wyeth and has been used clinically since 1967. Notably, iprindole was the first second-generation antidepressant to be launched.
Contents
Iprindole is unique compared to most other TCAs in that it is a relatively weak inhibitor of the reuptake of serotonin and norepinephrine and instead acts predominantly as an antagonist of 5-HT2 receptors, hence its classification as 'second-generation'. Additionally, side effects of iprindole are much less prominent relative to other TCAs and it is well tolerated. However, iprindole's efficacy may not be as great as other TCAs, especially in regards to anxiety relief.
Availability
Iprindole has been sold under the trade 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 as well.
Chemistry
On a structural level, iprindole differs from other TCAs in that it contains an indole nucleus, similarly to the heterocyclic antipsychotic oxypertine, and has an eight-membered and saturated third ring.
Pharmacology
Iprindole acts as an antagonist (or inverse agonist) of the following receptors:
And as an inhibitor of the following transporters:
It has negligible affinity (>10,000 nM) for β-adrenergic and sigma receptors.
Dosage
Iprindole is used in doses of 30–180 mg daily.
Side effects
Anticholinergic side effects such as dry mouth and constipation are either greatly reduced in comparison to imipramine and most other TCAs or fully lacking with iprindole. However, it still has potent antihistamine effects and therefore can produce sedation, though this is diminished relative to imipramine as well, perhaps due to iprindole lacking significant alpha-blocking properties.
Contraindications
Iprindole has been associated with jaundice and hepatotoxicity and should not be taken by alcoholics or people with pre-existing liver disease. If such symptoms are encountered iprindole should be discontinued immediately.
Interactions
Iprindole has been shown to be a potent inhibitor of the aromatic hydroxylation and/or N-dealkylation-mediated metabolism of many substances including, but not limited to octopamine, amphetamine, methamphetamine, fenfluramine, phenelzine, tranylcypromine, trimipramine, and fluoxetine, likely via inactivating cytochrome P450 enzymes. It also inhibits its own degradation.
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 half-lives by 2- to 3-fold, strongly augmenting both their physiological effects and neurotoxicity in the process.
Overdose
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. However, it should be noted that imipramine is prescribed much more often than iprindole, and for that reason this comparison is likely not entirely representative of iprindole's true capacity for fatality in overdose.