In fact, while all TCAs are SRIs and serotonin receptor antagonists to varying extents, the only TCAs that are associated with serotonin syndrome are clomipramine and to a lesser extent its dechlorinated analogue imipramine, which are the two most potent SRIs of the TCAs (and in relation to this have the highest ratios of serotonin reuptake inhibition to serotonin receptor antagonism). As such, whereas other TCAs can be combined with monoamine oxidase inhibitors (with caution due to the risk of hypertensive crisis from NET inhibition; sometimes done in treatment-resistant depressives), clomipramine cannot be due to the risk of serotonin syndrome and death. Unlike the case of its serotonin receptor antagonism, orthostatic hypotension is a common side effect of clomipramine, suggesting that its blockade of the α1-adrenergic receptor is strong enough to overcome the stimulatory effects on the α1-adrenergic receptor of its NET inhibition. Serotonergic activity
Clomipramine is a very strong SRI. Its affinity for the SERT was reported in one study using human tissues to be 0.14 nM, which is considerably higher than that of other TCAs. For example, the TCAs with the next highest affinities for the SERT in the study were imipramine, amitriptyline, and dosulepin (dothiepin), with Ki values of 1.4 nM, 4.3 nM, and 8.3 nM, respectively. In addition, clomipramine has a terminal half-life that is around twice as long as that of amitriptyline and imipramine. In spite of these differences however, clomipramine is used clinically at the same usual dosages as other serotonergic TCAs (100–200 mg/day).
Clomipramine, sold under the brand name Anafranil among others, is a tricyclic antidepressant (TCA). It is used for the treatment of obsessive–compulsive disorder, panic disorder, major depressive disorder, and chronic pain. It may increase the risk of suicide in those under the age of 25. It is taken by mouth. It has also been used to treat premature ejaculation.Common side effects include dry mouth, constipation, loss of appetite, sleepiness, weight gain, sexual dysfunction, and trouble urinating. Serious side effects include an increased risk of suicidal behavior in those under the age of 25, seizures, mania, and liver problems. If stopped suddenly a withdrawal syndrome may occur with headaches, sweating, and dizziness. It is unclear if it is safe for use in pregnancy. Its mechanism of action is not entirely clear but is believed to involve increased levels of serotonin.Clomipramine was discovered in 1964 by the Swiss drug manufacturer Ciba-Geigy. It is on the World Health Organizations List of Essential Medicines. It is available as a generic medication. Medical uses
Clomipramine has a number of uses in medicine including in the treatment of:

Obsessive–compulsive disorder (OCD) which is its only U.S. FDA-labeled indication. Other regulatory agencies (such as the TGA of Australia and the MHRA of the UK) have also approved clomipramine for this indication. Major depressive disorder (MDD) a popular off-label use in the US. It is approved by the Australian TGA and the United Kingdom MHRA for this indication.