Indication: For treatment of depression, including the depressed phase of bipolar depression, psychotic depression, and involutional melancholia, and may also be helpful in treating certain patients suffering severe depressive neurosis.
Pharmacology: Maprotiline is a tetracyclic antidepressant. Although its main therapeutic use is in the treatment of depression, it has also been shown to exert a sedative effect on the anxiety component that often accompanies depression. In one sleep study, it was shown that maprotiline increases the duration of the REM sleep phase in depressed patients, compared to imipramine which reduced the REM sleep phase. Maprotiline is a strong inhibitor of noradrenaline re-uptake in the brain and peripheral tissues, however it is worthy to note that it is a weak inhibitor of serotonergic uptake. In addition, it displays strong antihistaminic action (which may explain its sedative effects) as well as weak anticholinergic action. Maprotiline also has lower alpha adrenergic blocking activity than amitriptyline.
Mechanism Of Action: Maprotiline exerts its antidepressant action by inhibition of presynaptic uptake of catecholamines, thereby increasing their concentration at the synaptic clefts of the brain. In single doses, the effect of maprotiline on the EEG revealed a rise in the alpha-wave density, a reduction of the alpha-wave frequency and an increase in the alpha-wave amplitude. However, as with other tricyclic antidepressants, maprotiline lowers the convulsive threshold. Maprotiline acts as an antagonist at central presynaptic α2 adrenergic inhibitory autoreceptors and hetero-receptors, an action that is postulated to result in an increase in central noradrenergic and serotonergic activity. Maprotiline is also a moderate peripheral α1 adrenergic antagonist, which may explain the occasional orthostatic hypotension reported in association with its use. Maprotiline also inhibits the amine transporter, delaying the reuptake of noradrenaline and norepinephrine. Lastly, maprotiline is a strong inhibitor of the histamine H1 receptor, which explains its sedative actions.
Drug Category: Antidepressants; Adrenergic Uptake Inhibitors; ATC:N06AA21
Dosage Forms: TABLET (10, 25, 50, and 75mg film coated tablets)
Absorption: Completely absorbed following oral administration
Interactions:
DrugBank: Interactions for Maprotiline
Interactions for Maprotiline:
May interact with the following: alcoholic beverages, barbiturates, and other
CNS depressants (response may be exaggerated), adrenergic neuron blocking drugs (maprotiline may diminish or abolish
the antihypertensive effects of these drugs), beta-blockers subject to substantial biotransformation, such as
propranolol (concomitant use may increase the plasma concentrations of maprotiline), sympathomimetic drugs such as
noradrenaline, adrenaline, and methylphenidate (maprotiline may potentiate the cardiovascular effects of these
drugs), and maprotiline may also potentiate the effects of anticholinergic drugs (atropine, biperiden) and levodopa.
Drugs that activate hepatic microsomal enzymes, such as barbiturates, phenytoin, oral contraceptives and
carbamazepine, may accelerate the metabolism of maprotiline resulting in decreased antidepressant efficacy.
Concomitant administration of phenytoin and maprotiline may increase serum phenytoin levels resulting in
manifestation of the latter's side-effects. Concomitant treatment with maprotiline and major tranquilizers may result
in increased plasma levels of maprotiline, a lowered convulsion threshold, and seizures. The combination of
maprotiline and benzodiazepines may cause increased sedation. Maprotiline should not be administered for a period of
at least 14 days after the discontinuation of treatment with MAO-inhibitors due to the potential of severe
interactions. Concurrent use of parenteral magnesium sulfate and maprotiline may result in serious potentiation of
CNS depressant effects.
Chemical IUPAC Name: N-Methyl-9,10-ethanoanthracene-9(10H)-propanamine
