Maprotiline

Absorption

Slowly, but completely absorbed from the GI tract following oral administration.

Toxicity

LD50=~900 mg/kg (Orally in rats); LD50=90 mg/kg (Orally in women); Signs of overdose include motor unrest, muscular twitching and rigidity, tremor, ataxia, convulsions, hyperpyrexia, vertigo, mydriasis, vomiting, cyanosis, hypotension, shock, tachycardia, cardiac arrhythmias, impaired cardiac conduction, respiratory depression, and disturbances of consciousness up to deep coma.

Originator

Maprotiline hydrochloride ,Mylan

The Uses of Maprotiline

Antidepressant.

The Uses of Maprotiline

Maprotiline disrupts neuronal reuptake of monoamines in the CNS and possesses moderate tranquilizing and cholinergic activity. It improves mood significantly and relieves feelings of fear. Maprotiline is used in various forms of depression accompanied by a feeling of fear and irritability.

Background

Maprotiline is a tetracyclic antidepressant with similar pharmacological properties to tricyclic antidepressants (TCAs). Similar to TCAs, maprotiline inhibits neuronal norepinephrine reuptake, possesses some anticholinergic activity, and does not affect monoamine oxidase activity. It differs from TCAs in that it does not appear to block serotonin reuptake. Maprotiline may be used to treat depressive affective disorders, including dysthymic disorder (depressive neurosis) and major depressive disorder. Maprotiline is effective at reducing symptoms of anxiety associated with depression.

Indications

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.

Definition

ChEBI: Maprotiline is a member of anthracenes.

Manufacturing Process

9-(3-Hydroxypropyl)anthracene was prepared by reduction of 3-(9-anthryl) propionic acid with LiAlH4. By action of thionylchloride and then methylamine the 9-(3-hydroxypropyl)anthracene was converted to 9-(3-methylaminopropyl) anthracene. By addition of ethylene to 9-(3-methylaminopropyl)anthracene (at 150°C, a pressure of ethylene 50 atm, 24 hours) was obtained 3-(9,10- dihydro-9,10-ethanoanthracene-9-yl)-N-methylpropylamine. Hydrochloride 3- (9,10-dihydro-9,10-ethanoanthracene-9-yl)-N-methylpropylamine may be prepared by action hydrochloric acid.

Therapeutic Function

Antidepressant

Mechanism of action

Maprotiline is slowly but completely absorbed from the GI tract, and like the other TCAs, it is metabolized by the polymorphic CYP2D6 and CYP2C19 isoforms in the liver, primarily to pharmacologically active N-desmethylmaprotiline and to maprotiline-N-oxide.Maprotiline is distributed into breast milk at concentrations similar to those found at steady state in maternal blood. The elimination half-life of maprotiline averages 43 hours (60–90 hours for its N-desmethyl metabolite).Maprotiline shares the toxic potentials of the TCAs, and the usual precautions of TCA administration should be observed.

Pharmacokinetics

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 reuptake 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.

Clinical Use

Maprotiline is a secondary amine dibenzobicyclooctadiene (a tetracyclic antidepressant) that differs structurally from the TCAs by having an ethylene bridge in its central ring, resulting in a rigid bicyclomolecular skeleton .
Maprotiline exhibits the highest affinity and selectivity for the NE transporter. Its antidepressant mechanism of action is similar to that of desipramine, with an onset of action of up to 2 to 3 weeks.

Side Effects

Although most of the TCAs have been reported to induce seizures, it is generally recognized that maprotiline may be associated with a higher incidence of dose-dependent seizures compared with the other secondary TCAs. Maprotiline has been reported to produce sedation in depressed patients and to reduce aggressive behavior in animals. Maprotiline also shares the anticholinergic and cardiovascular effects of the secondary TCAs and may cause electrocardiographic changes, tachycardia, and postural hypotension.

Synthesis

Maprotiline, N-methyl-9,10-ethanoanthracen-9(10H)-propylamine (7.1.22), is synthesized by a 4
2 cycloaddition reaction of 9-(3-methylaminopropyl)anthracene with ethylene [39¨C41].

Maprotiline is frequently referred to as a tetracyclic antidepressant. This ?°hybrid?± drug, containing both elements of ?°classic tricyclic antidepressants?± and protriptyline elements, is pharmacologically and clinically more similar to imipramine.

Metabolism

Hepatic. Maprotiline is metabolized by N-demethylation, deamination, aliphatic and aromatic hydroxylations and by formation of aromatic methoxy derivatives. It is slowly metabolized primarily to desmethylmaprotiline, a pharmacologically active metabolite. Desmethylmaprotiline may undergo further metabolism to maprotiline-N-oxide.