Mostly, the Major Depressive Disorder (MDD) is described in simple terms as a condition of depression which lasts for two or more weeks. Majority of the patients go through from lack of interest or displeasure in most events in their every day activities. Similarly, difficulty in sleeping, lack of appetite, weak reasoning and lack of power are additional traits that expound on MDD circumstance. The victim might additionally experience traces of self-blame and worthlessness and might quit up committing suicide. Depression contributes a lot to chronic diseases such as coronary coronary heart disease, diabetes, and stroke. In a situation where despair continuously increases, the patients are likely to worsen their prognosis with medical conditions.
Selective Serotonin Reuptake Inhibitors (SSRIs)
SSRIs are groups of diverse chemical agents whose primary function is to inhibit Serotonin transporter (SERT). Fluoxetine was brought to the market by the United States in the year 1988 and rose drastically as the most available medication in the medical facilities, thus increasing the number of users in a therapeutic environment (Katzung, B. 2008, 512). The introduction of fluoxetine emerged at a time when there was a need to develop a chemical that would highly attract monoamine receptors. On the contrary, this medication was designed in a way that would frustrate the affinity of histamine, acetylcholine, and adrenoceptors that are classified in line with tricyclic antidepressants (TCAs).
Clinical pharmacology of Antidepressants
Clinical Indications of Depression
The Food and Drug Administration (FDA) has a broader strategy for the use of the antidepressants that aim in the treatment and reduction of both acute and moderate depressions. Majority of the antidepressants are eligible for handling both long term and short term medication of significant conditions of depression. The critical incidences of MMD tend to last for around 6-14 months when the situation is not treated. Conventionally, cases that go beyond 14 months to 2 years or more are minimal, and are approximately 20% of the total population affected by the condition (Katzung, B. 2008, 521). The aim of treating acute occurrences of MMD is to ensure reduction of the effects of the situation on the patients. The therapy may take a single trial period of 8-12 weeks to achieve maximum benefits of the antidepressants therapeutic dose. It is only about 30-40% of victims who can be healed within this time (Katzung, B. 2008, 521). When there is a small change in the application of medication, there is need to change the therapy through the introduction of new agents or accumulation of a new drug. In this situation, there is need to change the strategies and utilize augmentation which will oversee success in remission to around 70 to 80% of the patients (Katzung, B. 2008, 521). When the desired response is attained, a continuation therapy is designed that lasts for 6-12 months to ensure minimal chances of relapse. At least 85% of victims who have single incidences of MDD will relapse and reappear at least once in their lifespan (Katzung, B. 2008, 522). Many of these patients falling under the 85% category might end up suffering extreme recurrences which may progress to a more severe condition that will overcome the efforts of treatment; therefore it is of great importance to administer maintenance treatment that will reduce recurrences. To avoid chronic diseases that might appear as a result of repetitions, there is a need for the maintenance treatment to last for more than five years although it's somehow infrequent. Thus, it is highly recommended that patients should consider a long-term maintenance medication especially if there were two or more occurrences of MDD condition within five years.
As we had said earlier, the application of antidepressants is high in depression condition; which is then followed by anxiety disorders which include PTSD, OCD GAD, and panic disorder. Panic disorder is an anxiety condition that occurs as a result of frequent short-term episodes of overwhelming concerns. For instance, a person might fear to get involved in an attack or fear the situation in which the offense could occur. In comparison, GAD is a condition that is described when an individual has a chronic anxiety and unjustified fear that altogether seems to be prolonged (Dale, M. 2007, 570). The usage of older antidepressants and a sedative-hypnotic group of drugs has drastically reduced as treatment methods of anxiety diseases since the medical practitioners have upheld SSRIs and SNRIs strategies which have had a more significant impact.
Types of Antidepressants and their respective characteristics
Antidepressant Action Hazard of overdose Pharmacokinetics Clomipramine Nonselective The patient may suffer from ventricular Dysrhythmias which may be severe when combined with CNS depressants. T1/2 18_24 hours Fluoxetine very selective for 5_HT There have minimal danger but they must not be used together with MAO inhibitors. T1/2 24_96 hours
Mechanism of Action of Tricyclic Antidepressants
The principal function of the TCAs is to prevent the uptake of amines by the nerve endings. The TCAs does this by competing for the active sites of the amine carrier. Synthesis, storage, and release of the amines are not adversely affected, but some TCAs seem to indirectly boost the release of transmitters by obstructing the presynaptic α adrenoceptor (Dale, M. 2007, 562). Significant TCAs prevent the uptake of noradrenaline and 5_HT in the brain which on the other hand has minimal influence on the absorption of dopamine. In addition to the behavior of TCAs on the uptake of amines, most of them interfere with the functioning of several types of neurotransmitter receivers that include the histamine receptors, muscarinic acetylcholine receptors, and the 5_HT receptors (Dale, M. 2007, 563). In a situation where depression continuously increases, the patients are likely to worsen their prognosis with medical conditions. In conclusion, a state where depression continues to surge, the diagnosis of the victim is likely to deteriorate with an increase in the rate of treatment. Majority of depression conditions undergo various treatment procedures which include the treatment therapy, continuation therapy, and maintenance therapy respectively. Anxiety conditions are now treated by SSRIs and SNRIs procedures which have an added advantage over the use of old depressants.
Dale, M. (2007). Range and dale Pharmacology. Sixth edition, Chapter 39, pp.562-563, 570-571. Katzung, B. (2008). Basic and clinical pharmacology. Chapter 30, pp. 510, 514, 521-522