What is Iproniazid?

Which pills do you take when you are sad and need to elevate your mood? Mostly, these are antidepressants. One of them is iproniazid. 


This chemical element was introduced in the medical industry in 1958. It is the first drug of the monamine-oxidase inhibitor series. It was used widely as antidepressants until the iproniazid side effects came out to be liver damage. 


Before it was introduced, it was considered similar to the function of the antituberculosis drug isoniazid. This is similar in structure to iproniazid. But, what is the iproniazid structure? And how does it look like? 


Iproniazid Structure

The structure of iproniazid is:

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Its chemical formula is: C9H13N30

The iproniazid structure is chemically, in both structure and reactivity, similar to isoniazid. It is a small molecule that was developed as the first antidepressant. This molecule prevents the breakdown of norepinephrine. It is a brain neurotransmitter. This substance is concerned with emotional stimulation. This process happens mainly through the inhibition of enzyme monoamine oxidase. 

The molecular weight of iproniazid is 179.22. 

Its melting point is between 161-161.5

It is a carbohydrazide and a member of pyridines. 

Its name according to the IUPAC nomenclature is N'-propan-2-yl-pyridine-4-carbohydrazide. 

Iproniazid acts by increasing the size and concentration of granular vesicles. Moreover, it has a protective effect. 


Monoamine Oxidase Inhibitors

To treat the patients for tuberculosis pharmacologically, isoniazid and its derivatives were introduced in 1951. Iproniazid worked by inhibiting the enzyme MAO, becoming an iproniazid antidepressant and it worked by uplifting the mood of the patients. 


After gaining a deeper understanding of this drug, it was found out that this drug also benefitted in treating chronic pain. One of the most notable among them was an intractable headache. However, with this came the realization of its limit of clinical utility. 


But, with the introduction of TCAs, the MAOIs took a backfoot. The MAOIs are a heterogeneous group of drugs. They work by blocking the oxidative deamination of biogenic amines. This process leads to a release of larger-than-normal amounts of these amines. 


The MAOIs can be easily absorbed in the mouth, and their metabolization in the liver primarily takes place through acetylation. 


The most commonly used MAOIs are isocarboxazid, phenelzine and tranylcypromine. These are the non-selective inhibitors of MAO. Among them, phenelzine is the one that is used most commonly for the treatment of pain. Initially, the dose intake of phenelzine should be 15mg. But, with time, it can be increased by 15mg every week. The efficacy can dictate a total of 60mg. 


Even after this dose, if the patient does not get relief, they can additionally intake amitriptyline in a dose of 10mg. Do not abruptly discontinue the intake of phenelzine. 

FAQs (Frequently Asked Questions)

Q1. What are the Iproniazid Side Effects?

Ans. The precursor isoniazid and iproniazid were developed in the laboratories of Hoffman-la Roche, primarily serving as antituberculosis agents. After seeing the caustic observations of the mood-lifting properties of this element, its effects were confirmed in a clinical trial in 1957. However, during the treatment through iproniazid, hepatoxicity was observed. 


This subsequently led to the development of drugs that inhibited the MAO system. These included isocarboxazid, phenelzine and tranylcypromine. Their use is limited considering its possible hypertensive crises that take place after its ingestion. 

Q2. Why Has Iproniazid Been Withdrawn from Several Markets?

Ans. This action has been done in several countries, owing to the liver injuries that can be caused as a result of intake of this compound. The most common liver injury that happens due to its consumption is acute hepatocellular hepatitis. This typically happens within the first 3 three months of intaking the element. In case of discontinuation, this injury can last for up to 2 weeks.


Along with this, iproniazid also transforms into a reactive isopropyl radical. This happens to reactive the metabolites through monoamine oxidase, which accounts for the formation of M-6 antibodies.  

Q3. Is Iproniazid a Neurotransmitter?

Ans. Before its introduction as an antidepressant, iproniazid was studied as a drug similar in purpose to the anti-tuberculosis drug isoniazid, which it mirrors in chemical structure. Moreover, it prohibits the enzymatic breakdown of norepinephrine, the brain-neurotransmitter substance associated with emotional stimulation.