Antidepressant medicines are used to treat moderate and severe depression. They work by restoring the chemical imbalances in the brain that cause some of the symptoms of depression.

Choosing a treatment

There are many antidepressant medicines. Some work better for some people than others. When selecting an antidepressant for you, your doctor will prescribe the medication that appears to best suit your needs, taking into consideration

• your age
• your symptoms and their severity
• whether you have been depressed previously
• whether you have any other conditions or take any other medicines.

Starting treatment

You will usually start with a low dose, and gradually increase the dose over a period of 1–2 weeks until you reach the desired dose.

Before leaving the doctor’s surgery, make sure you understand how much medicine to take and how often to take it. If you think you may forget the instructions, ask the doctor to write them down.

Antidepressants take a while to work, so it may be 2–4 weeks before you notice any effect, and 4–8 weeks or more before you get the full effect.

Some people experience a worsening of some of their symptoms when they first start taking an antidepressant.

You will probably need to see the doctor every 1–2 weeks during the first few weeks. This will enable you to keep the doctor informed about your progress and any side effects you may be experiencing.

Side effects

Side effects are quite common, but don’t affect everyone. Most settle down in the first month.

Ask your doctor what side effects to watch out for, so you know what to expect. If you want more information, talk to your pharmacist or check the Consumer Medicine Information leaflet for your medicine.

Tell your doctor about any changes and side effects you experience, even if you are unsure whether they are due to the medication. Your doctor may be able to minimise the side effects by changing the dose of your medication or changing the time of day you take it.

Interactions

Antidepressant medicines can interact with some other medicines. For example, the herb St John’s wort and many cough and cold preparations can interact with some antidepressants to cause a potentially dangerous reaction.

To help avoid interactions, tell your doctor about all the other medicines you are taking, including any herbal, natural and pharmacy medicines.

Changing treatment

About 30–40% of people find they cannot tolerate the side effects of the first antidepressant they try or it does not work for them. If this happens, your doctor may recommend that you try another one. You will usually need to persevere with the first antidepressant for 4–6 weeks or more before trying another one.

With some antidepressants, you may need to take a break of a few days without medication before starting a new antidepressant medication. This break will give your body time to clear the old medication from your system, and prevent any interactions between the old and new medications.

Length of treatment

Once your symptoms have improved, you will probably be advised to continue taking your medication at the same dose.

While it may be tempting to stop the medication once you feel better, you are strongly advised not to do so. Stopping antidepressant medication too soon will increase your chances of having a relapse.

The length of your treatment will depend on the severity of your illness, how well the medicine works for you, and whether you have had depression previously. Some people will be able to stop their medication after 6–12 months, but others will need to take it for longer. Some will need to take it indefinitely.

Stopping treatment

Do not stop taking your medicine or reduce your dose without telling your doctor. Stopping some antidepressants abruptly may cause unpleasant effects, such as anxiety, insomnia, nausea, and pins and needles. Decreasing the dose over a period of weeks can prevent these effects occurring.

When stopping treatment, ask your doctor if you need to decrease the dose slowly, and what effects to watch out for.

If your illness recurs after stopping treatment, you will probably be advised to go back to your earlier dose and to continue treatment for at least another 3–6 months.

Further information

If you have any questions about your medication, talk to your doctor or pharmacist, ring Medicines Line, or read the medicine’s Consumer Medicine Information leaflet.