Common Forms of Anti-Depressants – and How They Work

Not all Anti-Depressant Drugs are alike….

Anti-depressants are a popular treatment choice for treating depression and anxiety. These medications reduce the symptoms of depression by balancing various neurotransmitters in the brain. However, you should keep in mind there is more to lifting depression then just with drugs. The most effective treatment of depression is a combination of psychotherapy and anti-depressants.

Anti-depressants are available in different forms, and each form has different action on the body. All these drugs balance the levels of neurotransmitters like serotonin, dopamine and nor-epinephrine.

The common forms of anti-depressant medications include:

Selective Serotonin Re-uptake Inhibitors (SSRIs)

These are the most commonly prescribed anti-depression drugs in Australia. Because of their fewer side effects, they are the preferred choice of treatment for this mood disorder. This class of anti-depression drugs are effective and well-tolerated. A newer anti-depressant is prescribed only in case the patient does not respond to SSRIs.

• Action – As the name suggests, SSRIs work by inhibiting the re-uptake of serotonin, and therefore increase the amount of serotonin available at nerve junctions.
• Examples – Some of the well-known SSRIs include Fluoxetine (Prozac, Lovan and Zactin), Citalopram (Cipramil and Ciazil), Fluvoxamine (Luvox and Faverin) and Sertraline (Zoloft).
• Side Effects – As compared to other forms of drugs for depression, Selective Serotonin Re-uptake Inhibitors cause fewer adverse effects. Some of the common side effects include nausea, weight gain, anxiety, restlessness, agitation, headaches and insomnia. These medications cause serious withdrawal effects if stopped abruptly.

Serotonin Norepinephrine Re-uptake Inhibitors (SNRIs)

These are a newer form of anti-depressants used in the treatment of major depression and other mental disorders. SNRIs were developed to reduce the significant weight gain and sexual dysfunction associated with serotonin re-uptake inhibition. They are not indicated in patients with heart condition.

• Action – The main action of SNRIs is on two neurotransmitters – serotonin and nor-epinephrine. These neurotransmitters play a vital role in uplifting your mood. According to some studies, low levels of nor-epinephrine are associated with symptoms of depression. Therefore, SNRIs work by increasing nor-ephinephrine levels, which in turn alleviates the symptoms and increase energy levels.
• Examples – Some of the common examples of SNRIs include levomilnacipran (Fetzima), duloxetine (Cymbalta), venlafaxine (Effexor XR) and desvenlafaxine (Pristiq, Khedezla).
• Side Effects – Some of the common side effects of SNRIs are nausea, fatigue, headache, increased sweating, insomnia, dizziness and decreased appetite.

Tricyclic Anti-depressants

These are the oldest form of drugs for mood disorders. They are not prescribed unless the patient stops responding to the newer forms of anti-depressants. They are found to be more effective in treating severe depression.

• Action – They work by binding to the neurotransmitter receptor sites located on the surface of nerve cells. This blocks the uptake of neurotransmitters and increases their concentration on the nerve junction.
• Examples – The common tricyclic anti-depressants include Clomipramine (Anafranyl), Nortriptyline (aventyl), Amitriptyline (Endep and Tryptanol), Trimipramine (Surmontil) and Desipramine (Norpramin).
• Side Effects – TCAs are known to have serious side effects, therefore, they are usually recommended as a second or third line of treatment for depression. Some of the side effects include weight gain, dry mouth, blurred vision and drowsiness. In case of overdose, they can be dangerous as they affect heart rhythm.

Monoamine Oxidase Inhibitors (MAOI’s)

These are among the oldest and less popular drugs for mental illness. They are known as the first generation treatments. Due to their severe side effects and food restrictions that must be observed while taking them, they are less commonly used for treating depression.

• Action – Unlike other forms of anti-depressants, MAOI’s do not prevent re-uptake of the chemical messengers or neurotransmitters. They work by inhibiting a slight degree of monamine oxidase, and thereby preventing the breakdown of the neurotransmitters. The action of monamine oxidase is to remove neurotransmitters from the brain. By breaking down monamine oxidase, MAOI’s increase the concentration of neurotransmitters, which in turn have an uplifting effect on mood.
• Examples – The commonly used MAOI’s include Phenelzine (Nardil), Tranylcypromine (Parnate), Isocarboxazid (Marplan) and Selegiline (Emsam).
• Side Effects – Some of the common side effects include insomnia, dry mouth, lightheadedness, dizziness, weakness, low blood pressure and sexual arousal. This form of drugs interfere with certain foods; therefore food restrictions need to be followed.

Nor-adrenalin Serotonin Specific Antidepressants (NaSSAs)

NaSSAs are a newer class of drugs for depression.

• Action – They alleviate symptoms in two ways – by increasing noradrenergic and serotenergic transmission and by blocking 5HT3 and 5HT2 receptors.
• Examples – The commonly prescribed NaSSAs in Australia include Mirtazapine (Avanza and Remeron).
• Side Effects – The side effects of NaSSAs are fewer as compared to other drugs. Some of the common effects include anxiety, sexual dysfunction, headache, nausea and vomiting.

Norepinephrine and dopamine reuptake inhibitors (NDRIs)

• Action – They work by inhibiting the neuronal reuptake of dopamine and norepinephrine.
• Examples – The commonly prescribed NDRIs include Bupropion (Wellbutrin, Aplenzin, Forfivo XL)
• Side Effects – The common side effects include anxiety, headache, nausea and vomiting.

Other less commonly used forms of anti-depressant drugs

• Augmentar drugs
• Reversible Inhibitor of Monamine Oxidase
• Mood stabilizers
• Antipsychotics

Each class or form of anti-depression medications has their own disadvantages and advantages. All of them have similar effects in terms of efficacy, but differ with respect to side effects and action.

To choose the right form of antidepressant, your doctor will consider various factors such as scope and severity of your symptoms, any previous history of mental disorders, existing medications, other treatments that you are taking for depression and possible side effects. Other factors like cost and insurance coverage are also taken into consideration while making a choice of medicine for mental illness.

When taking an antidepressant, you should take the medicine as scheduled according to the instructions as provided by your doctor. The side effects of anti-depression medications for mental illness are generally mild and temporary. Do not stop the medications abruptly. These medicines need to be tapered down gradually.

In case of any unusual side effects or reactions, consult your health care provider immediately. 

If you become concerned about any symptoms, please seek immediate medical attention we have some hotlines and suggested websites for further information and advice https://www.stayathomemum.com.au/my-kids/babies/important-hotlines-websites/

SAHM takes no responsibility for any illness, injury or death caused by misuse of this information. All information provided is correct at time of publication.