Dothiepin Vs Fluoxetine Mechanism Of Action And

10 October 2017

Dothiepin Vs. Fluoxetine ( Mechanism Of Action And Pharmacodynamics ) Essay, Research Paper

Comparison Between Mechanism of Action and Pharmacodynamics of Dothiepin and Fluoxetine

Description of medical specialties

Mechanism of action and pharmacodynamics


Dothiepin is a tricyclic antidepressant. It acts by advancing the effectivity of several aminoalkanes ( Dopastat, noradrenaline, and 5-hydroxytryptamine, which is besides known as 5HT and 5-hydroxytryptamine ) . It maps by suppressing their re-uptake at the terminuss of nervus cells, therefore taking to their drawn-out presence at the synaptic cleft and an increased consequence on the nerve cell. ( 1 ) The re-uptake pumps for the above aminoalkanes are responsible for cut downing the concentration of these aminoalkanes. Dothiepin works by barricading the pumps.

Harmonizing to the amine hypothesis, a reduced concentration of the aminoalkanes and the ensuing lessening in aminoalkane dependent synaptic transmittal is associated with depression, hence an addition in the above would assist alleviate the symptoms of depression. ( 2 )

Dothiepin has other actions as good.

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It reduces norepinephrine induced CAMP formation in the encephalon, every bit good as suppressing the consumption of 5HT into thrombocytes. It besides has some anticholinergic and antihistaminic activity. ( 3 )

Dothiepin begins to take consequence after about 2-3 hebdomads. Usual day-to-day doses of Dothiepin scope from 75mg to 200mg in the more terrible instances. ( 2 )


Fluoxetine belongs to a group of antidepressants known as the SSRI? s, or Selective 5-hydroxytryptamines reuptake inhibitors. It functions is similar to that of dothiepin above. It besides acts as a re-uptake inhibitor, but is extremely selective. It merely inhibits 5HT re-uptake, and lacks many of the less utile maps of dothiepin, such as the antihistaminic belongingss. ( 1 ) As above the consequence in addition in the presence of 5-hydroxytryptamine at the synaptic cleft consequences in a lessening in many symptoms of depression.

Fluoxetine does nevertheless hold some side effects including sickness, shudders, loss of libido and in some instances decreased sexual map. ( 2 ) It is besides possible that it may hold an consequence on Dopastat map. In some instances it besides reduces sleep efficiency. ( 3 )

Daily doses of Fluoxetine scope between 10mg and 60mg. However it has been found that effectivity does non look to be strongly related to dose. 20mg is every bit affectional as 40mg, and there is some grounds to propose that higher doses may be even less effectual. However the lower doses result in fewer and less sever inauspicious effects. ( 3 )

Adverse effects or inauspicious drug interactions


Adverse effects of dothiepin scope from potentially life endangering to mildly discomforting. Fatalities associated with dothiepin include cardiac failure, neonatal cardio-respiratory failure, myocardial infarction, arrhythmia, cardiac apprehension, ventricular fibrillation, shot, inborn bosom disease, hematemesis, aplastic anaemia, leucopenia, hepatorenal syndrome, cholestatic icterus, coma, neuroleptic malignant syndrome, aggravated Parkinson? s disease, intrauterine decease, nephritic failure, respiratory apprehension. These nevertheless are really rare. ( 1 ) Other terrible side effects include hepatitis, inappropriate ADH secernment, hypomania, and paroxysms. Psychotic manifestations, e.g. paranoid psychotic beliefs, may be brought about or worsened if already present. These symptoms are besides really uncommon, though less life endangering than those listed supra. ( 3 )

The less unsafe side effects are a spot more common, found in many patients, peculiarly those on higher doses of the drug. These include dry oral cavity, tachycardia, irregularity, sleepiness, sudating, sickness, purging, diarrhoea, shudder, roseolas, and intervention with sexual map. ( 3 )

The greatest dangers in overdose root from paroxysms, and the cardiac and respiratory effects listed supra. ( 3 )

Adverse drug interactions include MAO inhibitors and SSRI & # 8217 ; s as coincident disposal may take to increased plasma tricyclic degrees. CNS sedatives, including intoxicant will besides hold an increased consequence when taken in concurrences with dothiepin. Anesthetics may increase the hazard of arrhythmia. Antihypertensive agent activity may be reduced by dothiepin. Barbiturates may diminish the serum concentration of dothiepin, while methyl phenidate may increase it. Smoking may cut down the serum concentration of dothiepin by increasing its metamorphosis. ( 1 )


Fluoxetine appears to hold a lower incidence of inauspicious reactions, and these appear less terrible than those

associated with dothiepin. ( 2 )

Up to 1990 a sum of 11 deceases that may be associated with Prozac were recorded in patients. However these were non NECESSARILY associated with the drug. The potentially life baleful side effects included hyponatremia, which appeared to be reversible when the patients stopped taking the drug. A really few instances of vasculitis have besides been diagnosed. Cases of ictuss and ictus like episodes in Prozac patients have besides been recorded. Some patients developed passion. An incidence of 0.2 % has been estimated for these episodes. It has been suggested that Prozac may be associated with increased aggression and self-destructive inclinations. It appears that in some patients fluoxetine causes motor perturbations, which may be manifested through aggression, crossness, and in utmost instances, even moving on already self-destructive ideas frequently associated with depression. 15 out of 5000 New Zealand Prozac patients have been found to hold extrapyramidal effects associated with the Prozac. Less serious effects are more common, and include anxiousness, jitteriness, insomnia, sleepiness, weariness, shudder, sudating, GI ailments, anorexia, sickness, diarrhoea, and giddiness. Significant lift of hepatic enzymes besides occurred in 0.5 % of fluoxetine patients. A high incidence of sexual disfunction was besides observed. 30 % of patients suffered from this, including decreased rousing and libido, every bit good as hold or loss of orgasmic capacity. ( 3 )

In overdose Prozac is much safer than dothiepin. The chief danger comes from the ictuss. ( 1 )

Adverse drug interactions include MAO inhibitors, which can take to terrible and sometimes fatal reactions.

Tryptophan can do increased agitation, restlessness and g. i. hurt. Other antidepressants should besides be avoided, as Prozac greatly reduces their clearance. Lithium interacts with Prozac, although erratically. In some instances Lithium degrees have been seen to fall, in some to lift, even to toxic degrees. CNS active drugs warrant cautiousness when used at the same time with Prozac, as it will cut down their clearance, and increase their effects. ( 3 )



Dothiepin is administered orally and is quickly and good absorbed. It is likely that in the GI piece of land the soaking up is complete. Peak concentrations in plasma are reached 3 hours after the drug is taken. The mean half life of dothiepin is 22 hours, but it varies between 11 and 40 hours. ( 3 )

The unwritten clearance of dothiepin 1.4 The evident value of distribution is 45, but is likely slightly lower in world. There is non much fluctuation in pharmacokinetics between healthy and down patients. Dothiepin is mostly metabolized in the liver, and merely over half is excreted in piss during the following 24 hours. Elimination is lower in liver disease patients, nevertheless there is no clear clinical significance of this. ( 3 )


Fluoxetine is good absorbed in the GI piece of land, whatever the dose signifier. Average clip to top out plasma concentration is about 6-8 hours. Fluoxetine is metabolized to norfluoxetine, which is besides a powerful antidepressant. ( 3 )

Flouxetine does non look to hold additive dynamicss. Higher doses result in disproportionately higher drug concentrations, most likely due to impregnation of the metabolic tracts in the liver, where Prozac is metabolized. Fluoxetine has an mean half life of 48 to 72 hours, and it? s metabolite, norfluoxetine has a half life of 6.1 yearss. The high half life is the consequence of plasma membrane binding and a high volume of distribution ( 42 ) ( 3 )

As was mentioned above, Prozac is metabolized in the liver. 60-80 % is excreted in piss, and about 15 % in fecal matters. Renal damage has really small consequence on the pharmacokinetics, but hepatic damage badly decreases clearance. ( 3 )


( 1 ) Psychopharmacology: The 4th coevals of advancement ; Bloom F E, Kupfer D J ; Raven Press ; 1995

( 2 ) Basic and clinical pharmacological medicine ; Katzung B G ; Appleton and Lange ; 1998

( 3 ) Therapeutic drugs. Had to give this one dorsum before I finished with it, so no saloon info. Necessitate to look up on Library com

( 1 ) Psychopharmacology: The 4th coevals of advancement ; Bloom F E, Kupfer D J ; Raven Press ; 1995

( 2 ) Basic and clinical pharmacological medicine ; Katzung B G ; Appleton and Lange ; 1998

( 3 ) Therapeutic drugs. Had to give this one dorsum before I finished with it, so no saloon info. Necessitate to look up on Library com

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