Types of Antidepressants
Antidepressants are plan to act on neurotransmitters at the site of the synaptic cleft. Neurotransmitter release and re-uptake are the neurons' ways of communicating with each other. Low levels of neurotransmitters, in single serotonin, noradrenaline and dopamine are plan to be connected with depressive disorders. Antidepressants are plan to inhibit re-uptake, boost production or preclude the breakdown of neurotransmitters thus boosting their action to regulate mood and alleviate depression.
Types of Antidepressants
There are at least 20 different antidepressants available. Although all (to some extent) will potentially alleviate the symptoms of depression, choosing the right antidepressant for a exact sick person is dependent upon a amount of factors such as the type of depressive disorder, possible side-effects, interactions with other medications and other healing conditions. Antidepressants may be grouped into four main classes:
1. Monoamine oxidase inhibitors (Maois)
2. Tricyclic antidepressants (Tcas)
3. Selective serotonin reuptake inhibitors (Ssris)
4. Atypical antidepressants
But there are two other types of medications also used in the medicine of mood disorders: dual-action antidepressants and mood stabilisers.
Monoamine oxidase inhibitors (Maois) were some of the earliest medications to be used as antidepressants in the 1950s. These medications work by inhibiting the action of an enzyme called monoamine oxidase which destroys norepinephrin. By preventing the destruction of these neurotransmitters, these chemicals are able to remain in the synaptic space for a longer period of time and thus help to alleviate depression. The oldest and most common drugs of this class are Nardil (phenelzine) and Parnate (tranylcypromine) which irreversibly bind to the enzyme Mao.
However, Mao is also responsible for regulating a amount of other biological processes together with the metabolism of tyramine which is found in many foods, and to metabolise sympathomimetic amines which are found in many decongestants, cold and flu remedies, allergy medications and appetite suppressants. Problems, such as high blood pressure, occur when tyramine and other substances are unmetabolised causing headache, nausea, vomiting, stroke or death in some cases. Thus it is very foremost that patients disclose to their general practitioner all other medications that may be ingested.
These are some of the foods that need to be avoided in conjunction with the older Maois:
o All cheeses except bungalow cheese and cream cheeses
o Beer and red wine, some spirits, liqueurs and nonalcoholic beer
o Soybeans, fava beans and bean curd
o Smoked, fermented, aged, or pickled fish
o Ginseng, St. John's wort, and medication containing 5-Htp
o Sauerkraut
o Shrimp paste
o Aged or processed meats such as sausage or salami
o Yeast citation or brewer's yeast
o Other foods such as some white wines and port, caffeine, chocolate, dairy products, nuts, raspberries, and spinach can only be consumed in small quantities.
Because of their possible risks, the older Maois tend only to be used if the other antidepressant classes have been trialled and have failed. Maois may be productive in the medicine of melancholic depression, when Ssris and other narrow action and dual action drugs have failed, because of their broad range of action on the different neurotransmitter systems. Newer Maois, which are reversible inhibitors of the enzyme Mao, are safer and contain medications such as moclobemide (Aurorix).
Tricyclic Antidepressants (Tcas) were industrialized in the 1950s originally as a medicine for schizophrenia. Until the arrival of the Ssris, any way Tcas were the medicine of option for depressive disorders. The Tcas which contain drugs such as Tofranil (imipramine), Allegron (nortriptyline), Sinequan (doxepin) and Endep (amitryptyline) are plan to inhibit the reuptake of neurotransmitters in the synaptic cleft and thus ease depression. They can also stimulate appetite, increase action levels, and heighten sleep. Because of their broad range of action of the different neurotransmitter pathways, tricyclic antidepressants are also particularly useful in the medicine of melancholic depression when Ssris have failed.
While safer in some respects than the Maois, the Tcas are not recommended for people with glaucoma, heart disease, a history of seizures, hyperthyroidism, or urinary retention. In addition, they are contraindicated for people with liver or kidney disease. Often people complain that they feel hung over or overly sedated with the Tcas and in the elderly this side result together with another side result of lowered blood pressure can result in falls and fractures. Overdose with Tcas can be fatal making them unsuitable for depressed people with a high suicide risk.
If by emergency they are used with Maois, the results can be fatal (seizures and stroke). Toxic blood levels can also occur if they are taken with antiarrhythmic drugs.
Selective Serotonin Reuptake Inhibitors (Ssris) such as Prozac (fluoxitine), Zoloft (sertraline), Cipramil (citalopram), Luvox (fluvoxamine), Lexapro (escitalopram) and Aropax (paroxetine) act on blocking the reuptake of serotonin and thus help to alleviate depressed mood. Not only are Ssris safer than the Maois and the Tcas but they also cause fewer and less disturbing side effects. However, the problems of sexual dysfunction (such as the inability to reach orgasm, erection problems, loss of lubrication in women and decreased libido) affecting up to 50% of patients following the use of this class of medications can lead to its discontinuation.
The mixture of Ssris with Maois is lethal but they also should not be taken with Tcas, antipsychotic, or anticonvulsant drugs, as they inhibit the liver's capability to metabolise them. Thus toxic levels of Ssris can build up in the blood. A health known as serotonin syndrome (described later) can develop, especially if these drugs are ingested with St John's Wort.
Dual-action antidepressants Some of the newer antidepressants target more that one neurotransmitter ideas (usually serotonin and noradrenaline) in the brain. Medications that fall into this group are venlafaxine (Efexor) and mirtazapine (Avanza). Venlafaxine is also plan to block the reuptake of dopamine, especially in high doses, while in low doses only the serotonin ideas may be affected and at medium doses both the serotonin and noradrenalin systems may be affected.
Atypical antidepressants are so named because they do not fit into the usual drug classes described above. One of these medications is Zyban (buproprion) which inhibits the reuptake of both noradrenalin and dopamine, and which is generally used to help people quit smoking, but causes serious problems such as seizures if taken with alcohol and other adverse reactions if taken with Maois. people taking this medication can return abnormal Ecgs and demonstrate a drop in their white blood cell count.
Mood Stabilisers Among people who are suffering from a depressive disorder within a bipolar illness, antidepressants such as tricyclics and Maois can cause a rapid shift into mania (referred to as Bipolar Iii) or increase the frequency of cycling between depression and mania. If antidepressants are used, these possible mood shifts need to be closely monitored.
There are other medications which may also be used to treat bipolar disorder together with antiepileptics such as Tegretol (carbamazepine), Epilim (sodium valproate) and Lamictal (lamotrigine). medicine with Tegretol can sometimes result in lowered concentrations of red and white blood cells and the medication can interfere with the effects of birth control pills.
Treatment Regimen
The aim of antidepressant medication therapy is to accomplish the best result with the lowest dose possible and the fewest or least disabling side-effects. Starting doses for the antidepressants are ordinarily low so that patients can be monitored for side-effects, get used to the medication regimen and moderately build up their blood levels of the drug. The earliest signs of revising following the commencement of antidepressant medicine are generally in sleep and appetite.
Improvements in mood occur moderately and changes are ordinarily first noticed by friends and family. Patients ordinarily observation an revising in 2 to 3 weeks and the full effects of the medication should be felt by 6 weeks. Most patients will remain on antidepressants for some months even after remission of symptoms. However, the distance of time that anyone remains on any one medication is dependent upon a amount of factors together with either or not their stressors (if any) have resolved, if they have a strong house history of depressive disorders, and either they suffer from recurrent bouts of depression.
The Ssris tend to be used as first-line antidepressants and a few may be trialled before settling on one. If they are ineffective however, then the atypical antidepressants or Tcas, and more rarely the Maois, may be used. Sometimes, doctors may prescription a mixture of medications to accomplish the best results. When switching classes of medications, patients may have to feel a "washout" stage during which they may have to moderately sell out the dose of their original medication and palpate a short drug-free period. during this time, depressive symptoms may worsen and patients may palpate some resignation effects such as dizziness, headaches, sleep disturbances, nausea, or gastrointestinal upset.
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