Venlafaxine is an arylalkanolamine serotonin-norepinephrine reuptake inhibitor, which is sold under several brand names; one of them is venlafaxine hydrochloride. Venlafaxine hydrochloride is a venlafaxine extended release tablets, which are indicated for the treatment of major depressive disorder (MDD). Efficacy of venlafaxine in MDD was shown in both short-term trials and a longer-term trial in MDD. A major depressive episode (DSM-IV) implies a prominent and relatively persistent depressed mood or the loss of interest or pleasure in nearly all activities, representing a change from previous functioning, and includes the presence of at least five of the following nine symptoms during the same two-week period. In addition, venlafaxine hydrochloride is indicated for the treatment of social anxiety (SAD), also known as social phobia. Social Anxiety Disorder (DSM-IV) is characterized by a marked and persistent fear of 1 or more social or performance situations in which others expose to unfamiliar people or to possible scrutiny the person. Exposure to the feared situation almost invariably provokes anxiety, which may approach the intensity of a panic attack. The feared situations are avoided or endured with intense anxiety or distress. The mechanism of the antidepressant action of venlafaxine in humans is believed to be associated with its potentiation of neurotransmitter activity in the CNS. Preclinical studies have shown that venlafaxine and its active metabolite, O-desmethylvenlafaxine (ODV), are potent inhibitors of neuronal serotonin and norepinephrine reuptake and weak inhibitors of dopamine reuptake.

Sertraline (trade names Zoloft and others) is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. Sertraline is primarily prescribed for major depressive disorder in adult outpatients as well as obsessive-compulsive disorder, panic disorder, and social anxiety disorder, in both adults and children. The exact mechanism of action sertraline is not fully known, but the drug appears to selectively inhibit the reuptake of serotonin at the presynaptic membrane. This results in an increased synaptic concentration of serotonin in the CNS, which leads to numerous functional changes associated with enhanced serotonergic neurotransmission. It is suggested that these modifications are responsible for the antidepressant action observed during long-term administration of antidepressants. It has also been hypothesized that obsessive-compulsive disorder is caused by the dysregulation of serotonin, as it is treated by sertraline, and the drug corrects this imbalance. Compared to other SSRIs, sertraline tends to be associated with a higher rate of psychiatric side effects and diarrhea. It tends to be more activating (that is, associated with a higher rate of anxiety, agitation, insomnia, etc.) than other SSRIs, aside from fluoxetine. Over a two-week treatment of healthy volunteers, sertraline slightly improved verbal fluency but did not affect word learning, short-term memory, vigilance, flicker fusion time, choice reaction time, memory span, or psychomotor coordination. In spite of lower subjective rating, that is, feeling that they performed worse, no clinically relevant differences were observed in the objective cognitive performance in a group of people treated for depression with sertraline for 1.5 years as compared to healthy controls

Bupropion, an antidepressant of the aminoketone class and a non-nicotine aid to smoking cessation, is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitor, or other known antidepressant agents. Compared to classical tricyclic antidepressants, Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine, serotonin, and dopamine. In addition, Bupropion does not inhibit monoamine oxidase. Bupropion produces dose-related central nervous system (CNS) stimulant effects in animals, as evidenced by increased locomotor activity, increased rates of responding in various schedule-controlled operant behavior tasks, and, at high doses, induction of mild stereotyped behavior. Bupropion is marketed as Wellbutrin, Zyban, and generics. Bupropion is indicated for the treatment of major depressive disorder (MDD). WELLBUTRIN, WELLBUTRIN SR, and WELLBUTRIN XL are not approved for smoking cessation treatment, but bupropion under the name ZYBAN is approved for this use.

Amoxapine is an antidepressant of the dibenzoxazepine class, chemically distinct from the dibenzazepines, dibenzocycloheptenes, and dibenzoxepines. It is designated chemically as 2-Chloro-11- (1-piperazinyl)dibenz[b,f ][1,4]oxazepine. Amoxapine is an antidepressant with a mild sedative component to its action. The mechanism of its clinical action in man is not well understood. In animals, amoxapine reduced the uptake of norepinephrine and serotonin and blocked the response of dopamine receptors to dopamine. Amoxapine is not a monoamine oxidase inhibitor. Amoxapine is absorbed rapidly and reaches peak blood levels approximately 90 minutes after ingestion. It is almost completely metabolized. The main route of excretion is the kidney. In vitro tests show that amoxapine binding to human serum is approximately 90%. In man, amoxapine serum concentration declines with a half-life of eight hours. However, the major metabolite, 8-hydroxyamoxapine, has a biologic half-life of 30 hours. Metabolites are excreted in the urine in conjugated form as glucuronides. Clinical studies have demonstrated that amoxapine has a more rapid onset of action than either amitriptyline or imipramine. The initial clinical effect may occur within four to seven days and occurs within two weeks in over 80% of responders.

Protriptyline (trade name Vivactil) is a tricyclic antidepressant, indicated for the treatment of depression. Protriptyline acts by decreasing the reuptake of norepinephrine and to a lesser extent serotonin (5-HT) in the brain. Tricyclic antidepressants act to change the balance of naturally occurring chemicals in the brain that regulate the transmission of nerve impulses between cells. Protriptyline increases the concentration of norepinephrine and serotonin (both chemicals that stimulate nerve cells) and, to a lesser extent, blocks the action of another brain chemical, acetylcholine. The therapeutic effects of protriptyline, like other antidepressants, appear slowly. Maximum benefit is often not evident for at least two weeks after starting the drug. Protriptyline is used primarily to treat depression and to treat the combination of symptoms of anxiety and depression. Like most antidepressants of this chemical and pharmacological class, protriptyline has also been used in limited numbers of patients to treat panic disorder, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, enuresis, eating disorders such as bulimia nervosa, cocaine dependency, and the depressive phase of bipolar disorder (manic-depressive) disorder. It has also been used to support smoking cessation programs. Like all tricyclic antidepressants, protriptyline should be used cautiously and with close physician supervision. This is especially so in the elderly, or people who have benign prostatic hypertrophy (enlarged prostate gland), or urinary retention, or glaucoma, especially angle-closure glaucoma (the most severe form). Before starting treatment, people should discuss the relative risks and benefits of treatment with their doctors to help determine if protriptyline is the right antidepressant for them. A common problem with tricyclic antidepressants is sedation (drowsiness, lack of physical and mental alertness), but protriptyline is considered the least sedating agent among this class of agents. Its side effects are especially noticeable early in therapy. In most people, early tricyclic side-effects decrease or disappear entirely with time, but, until then, patients taking protriptyline should take care to assess which side-effects occur in them and should not perform hazardous activities requiring mental acuity or coordination. The side-effects are increased when protriptyline is taken with central nervous system depressants, such as alcoholic beverages, sleeping medications, other sedatives, or antihistamines, as well as with other antidepressants including SSRIs, SNRIs or monoamine oxidase Inhibitors.

Nortriptyline is a second-generation tricyclic antidepressant (TCA) marketed as the hydrochloride salt under the trade names Sensoval, Aventyl, Pamelor, Norpress, Allegron, Noritren and Nortrilen. Nortriptyline is used in the treatment of depression and childhood nocturnal enuresis. Its off-label uses include treatment of postherpetic neuralgia, angioedema and smoking Cessation, and attention deficit hyperactivity disorder in some neurological disorders. It is believed that nortriptyline either inhibits the reuptake of the neurotransmitter serotonin at the neuronal membrane or acts at beta-adrenergic receptors. Nortriptyline is US FDA-approved for the treatment of major depression. In the United Kingdom, it may also be used for treating nocturnal enuresis, with courses of treatment lasting no more than three months. The most common side effects include dry mouth, sedation, constipation, and increased appetite, mild blurred vision, tinnitus, occasionally hypomania or mania. An occasional side effect is a rapid or irregular heartbeat. Alcohol may exacerbate some of its side effects. However, fewer and milder side effects occur with nortriptyline than tertiary tricyclic antidepressants such as imipramine and amitriptyline. For this reason, nortriptyline is preferred to other tricyclic antidepressants, particularly with older adults, which also improves compliance.

Desipramine is a tricyclic antidepressant that was approved by the FDA in 1964. It was derived from imipramine, which was the first tricyclic antidepressant to be manufactured. Desipramine is one of many tricyclic antidepressants, and this type of antidepressant gets its name due to its three-ring chemical structure. Desipramine, a secondary amine tricyclic antidepressant, is structurally related to both the skeletal muscle relaxant cyclobenzaprine and the thioxanthene antipsychotics such as thiothixene. It is the active metabolite of imipramine, a tertiary amine TCA. The acute effects of desipramine include inhibition of noradrenaline re-uptake at noradrenergic nerve endings and inhibition of serotonin (5-hydroxy tryptamine, 5HT) re-uptake at the serotoninergic nerve endings in the central nervous system. Desipramine exhibits greater noradrenergic re-uptake inhibition compared to the tertiary amine TCA imipramine. In addition to inhibiting neurotransmitter re-uptake, desipramine down-regulates beta-adrenergic receptors in the cerebral cortex and sensitizes serotonergic receptors with chronic use. The overall effect is increased serotonergic transmission. Antidepressant effects are typically observed 2 - 4 weeks following the onset of therapy though some patients may require up to 8 weeks of therapy prior to symptom improvement. Patients experiencing more severe depressive episodes may respond quicker than those with mild depressive symptoms. Desipramine is marketed under the trade name Norpramin, indicated for the treatment of depression.

Phendimetrazine is an appetite suppressant that is FDA approved for the treatment of exogenous obesity. It is clinically available anorectic agent, which display minimal interactions with monoamine transporters in vitro. On the other hand, their medications is known to be psychomotor stimulants when administered in vivo as indicated by their shared properties with illicit drugs like cocaine. The following adverse reactions are described, or described in greater detail, in other sections: Primary pulmonary hypertension; Valvular heart disease; Effect on the ability to engage in potentially hazardous tasks; Withdrawal effects following prolonged high dosage administration. Use of phendimetrazine tartrate is contraindicated during or within 14 days following the administration of monoamine oxidase inhibitors because of the risk of hypertensive crisis.

Phentermine is an amphetamine that stimulates neurons to release or maintain high levels of a particular group of neurotransmitters known as catecholamines; these include dopamine and norepinephrine. High levels of these catecholamines tend to suppress hunger signals and appetite. The drug seems to inhibit reuptake of noradrenaline, dopamine, and seratonin through inhibition or reversal of the reuptake transporters. It may also inhibit MAO enzymes leaving more neurotransmitter available at the synapse. Phentermine (through catecholamine elevation) may also indirectly affect leptin levels in the brain. It is theorized that phentermine can raise levels of leptin which signal satiety. It is also theorized that increased levels of the catecholamines are partially responsible for halting another chemical messenger known as neuropeptide Y. This peptide initiates eating, decreases energy expenditure, and increases fat storage. Phentermine is indicated in the management of exogenous obesity as a short term (a few weeks) adjunct in a regimen of weight reduction based on caloric restriction. Phentermine hydrochloride is a sympathomimetic amine with pharmacologic activity similar to the prototype drugs of this class used in obesity, the amphetamines. Actions include central nervous system stimulation and elevation of blood pressure. Tachyphylaxis and tolerance have been demonstrated with all drugs of this class in which these phenomena have been looked for.

Imipramine is a tricyclic antidepressant with general pharmacological properties similar to those of structurally related tricyclic antidepressant drugs such as amitriptyline and doxepin. A tertiary amine, imipramine inhibits the reuptake of serotonin more so than most secondary amine tricyclics, meaning that it blocks the reuptake of neurotransmitters serotonin and noradrenaline almost equally. With chronic use, imipramine also down-regulates cerebral cortical β-adrenergic receptors and sensitizes post-synaptic sertonergic receptors, which also contributes to increased serotonergic transmission. It takes approximately 2 - 4 weeks for antidepressants effects to occur. The onset of action may be longer, up to 8 weeks, in some individuals. It is also effective in migraine prophylaxis, but not in abortion of acute migraine attack. Imipramine works by inhibiting the neuronal reuptake of the neurotransmitters norepinephrine and serotonin. It binds the sodium-dependent serotonin transporter and sodium-dependent norepinephrine transporter preventing or reducing the reuptake of norepinephrine and serotonin by nerve cells. Depression has been linked to a lack of stimulation of the post-synaptic neuron by norepinephrine and serotonin. Slowing the reuptake of these neurotransmitters increases their concentration in the synaptic cleft, which is thought to contribute to relieving symptoms of depression. In addition to acutely inhibiting neurotransmitter re-uptake, imipramine causes down-regulation of cerebral cortical beta-adrenergic receptors and sensitization of post-synaptic serotonergic receptors with chronic use. This leads to enhanced serotonergic transmission. Used for relief of symptoms of depression and as temporary adjunctive therapy in reducing enuresis in children aged 6 years and older. May also be used to manage panic disorders, with or without agoraphobia, as a second line agent in ADHD, management of eating disorders, for short-term management of acute depressive episodes in bipolar disorder and schizophrenia, and for symptomatic treatment of postherpetic neuralgia.