Trimipramine
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Trimipramine
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| Systematic (IUPAC) name | |
| 3-(10,11-Dihydro- 5H-dibenz[b,f]azepin-5-yl)- N,N,2-trimethylpropylamin) | |
| Identifiers | |
| CAS number | |
| ATC code | N06 |
| PubChem | |
| DrugBank | |
| Chemical data | |
| Formula | C20H26N2 |
| Mol. mass | 294.434 |
| Pharmacokinetic data | |
| Bioavailability | 40% |
| Metabolism | Hepatic |
| Half life | 11 to 23 hours, depending on metabolizer type (rapid or slow) |
| Excretion | Renal |
| Therapeutic considerations | |
| Pregnancy cat. |
? |
| Legal status |
℞ Prescription only |
| Routes | Oral, im, iv |
Trimipramine is an tricyclic antidepressant with sedative and anxiolytic properties and available as Stangyl, Surmontil, Rhotrimine and generic forms.
Contents |
[edit] Pharmacology
Trimipramine's mechanism of action differs from other tricyclic antidepressants. It is only a moderate reuptake inhibitor of norepinephrine, and a weak reuptake inhibitor of serotonin and dopamine. The main effects are due to considerable postynaptic blockade as follows:
- strong : 5-HT2, Muscarinic, H1, H2, Alpha1
- moderate : D2
- weak : 5-HT1, Alpha2
The spectrum of effects (strong antidepressant activity, sedation and anxiolysis) and side-effects (strong anticholinergic and antiadrenergic side-effects) is the same as with Doxepin. It is also a more effective sedative than Amitriptyline. Trimipramine is the only effective drug against insomnia known so far that does not alter the normal sleep architecture. In particular, it does not suppress REM-sleep, and dreams are said to brighten during treatment.[citation needed] However, this can occasionally go too far, as nightmares are an uncommon but possible side effect of the drug. Its relatively strong antagonistic activity at postsynaptic D2-receptors led to a clinical study trying Trimipramine as atypical neuroleptic. There it exerted good antipsychotic activity with a low incidence of extrapyramidal and other side-effects. But this study encompassed only 28 patients, so the use of Trimipramine as a neuroleptic needs further confirmation and can currently not be recommended. Trimipramine shows also useful activity against chronic pain.
[edit] Metabolism
Trimipramine is a racemic compound with two enantiomers. CYP2C19 is responsible for the demethylation of (D)- and (L)-trimipramine to (D)- (L)-desmethyltrimipramine, respectively, and CYP2D6 is responsible for the 2-hydroxylation of (D)- and (L)-desmethyltrimipramine to (D)- and (L)-2-hydroxydesmethyltrimipramine, respectively.[1] CYP2D6 also metabolizes (L)-trimipramine into (L)-2-hydroxytrimipramine.[1]
[edit] Indications
- Endogenous and neurotic depression with prominent agitation and anxiety
- Depressive and non-depressive insomnia (suitable for long-term treatment)
- Adjunctive therapy of alcohol and opioid withdrawal
- Chronic pain of malignant and non-malignant origin
Trimipramine is an efficient antidepressant, sedative, and anxiolytic comparable to Doxepin.
[edit] Contraindications
absolute :
- concomitant treatment with MAO-Inhibitors
- known hypersensitivity to Trimipramine or other Tricyclics
- acute intoxication with alcohol, sedatives, analgesics and other psychoactive drugs
- acute Delirum tremens
- untreated closed angle glaucoma
- hypertrophy of the prostate with urine retention
- paralytic ileus
relative :
- hypertrophy of the prostate without urine retention
- reduced function of the bone marrow
- organic brain disorders
- increased risk of seizures, preexisting epilepsy
- preexisting cardial damage, particular some arrhythmias (impulse conductive disorders)
[edit] Side effects
- Further information: Doxepin
All side-effects of Doxepin are noted also during Trimipramine use with approximately the same frequency and intensity in equivalent doses.
Additionally, very unusual hypersensitivity reactions involving blood (eosinophilia), liver (diffuse liver damage), lung (eosinophilic pleuritis) and flu-like symptoms have been rarely noted and should be carefully watched for.
[edit] Interactions
With other centrally active substances and drugs that interfere with the metabolization and elimination.
[edit] Drug abuse and dependence
Trimipramine is not an abusable substance nor does it cause psychological dependence.
Withdrawal symptoms frequently seen when treatment with Trimipramine is stopped abruptly (agitation, anxiety, insomnia, sometimes activation of mania or rebound depression) are not indicative of addiction and can be avoided by reducing the daily dose of Trimipramine gradually by approximately 25% each week. If treatment has to be stopped at once due to medical reasons, the use of a benzodiazepine (e.g. Lorazepam, Clonazepam, or Alprazolam) for a maximum of 4 weeks as needed will usually suppress withdrawal symptoms.
[edit] Necessary examinations during treatment
The examinations needed depend on the risk profile of the patient. In most cases, particular with high doses, frequent blood pressure and EKG-profiles are indicated. All patients should have periodical laboratory checks including white bloodcell counts, liver-, and kidney-function tests. Patients with risks for development of seizures may also need EEG-examinations.
[edit] Dosage
Whilst some standard suggested dosages are published for the treatment of depression, the proper dosage for treatment of insomnia in non-depressive patients, those on alcohol/opioid withdrawal and those with chronic pain may vary greatly and should be discussed with your physician.
Treatment should be initiated at the lowest recommended dose and increased gradually, noting carefully the clinical response and any evidence of intolerance. Days to weeks may elapse before optimal therapeutic effects of Trimipramine are seen. Increasing the dosage usually does not shorten this latent period and may increase the incidence of side effects and patient non-compliance.
In elderly or debilitated patients it may be necessry to check blood pressure and cardiac rhythm, particularly in patients who have unstable cardiovascular function.
Once a satisfactory response has been obtained, the dosage is normally adjusted to the lowest level required to maintain remission and avoid relapse. Medication should be continued for the expected duration of the depressive episode in order to minimize the possibility of relapse following clinical improvement. Afterwards, prophylactic treatment for 1 to 2 years may be indicated, but there are different opinions regarding the optimal dose and length of remission maintenance treatment.
[edit] Parenteral usage
Intramuscular injections and slow i.v.-infusions are possible, but have the disadvantage of intensified anticholinergic and antiadrenergic side-effects. The advantage may be an earlier onset of action compared to oral dosage. Decreased doses are sufficient with parenteral treatment.
[edit] Usual dosage forms
- tablets/capsules 10, 12.5, 25, 50, 75, 100, 150mg
- liquid concentrate (40mg/ml)
- injectable concentrate (25mg)
[edit] References
- B. Bandelow, S. Bleich, S. Kropp : Handbuch Psychopharmaka (German), 2nd. edition, 2004
- Barocka et al. : Psychopharmakatherapie in Klinik und Praxis (German), 1998
- Benkert, Hippius : Kompendium der Psychiatrischen Pharmakotherapie, 4th. edition, 2003
- Drug monograph
[edit] Footnotes
- ^ a b Eap CB, Bender S, Gastpar M, et al (2000). "Steady state plasma levels of the enantiomers of trimipramine and of its metabolites in CYP2D6-, CYP2C19- and CYP3A4/5-phenotyped patients". Ther Drug Monit 22 (2): 209–14. PMID 10774635.
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