Cautions and interactions 

There are several important things to consider when taking antidepressants. You should discuss these with your GP or mental health professional.

Interactions with other medications

Antidepressants can react unpredictably with other medications, including over-the-counter medications such as ibuprofen. Always read the patient information leaflet that comes with your medication to see if there are any medications you should avoid.

If in doubt, your pharmacist or GP should be able to advise you.

Pregnancy

As a precaution, antidepressants aren't usually recommended for most pregnant women, especially during the early stages of a pregnancy. However, exceptions can be made if the risks posed by depression (or other mental health conditions) outweigh any potential risks of treatment.

Potential complications that have been linked to antidepressant use during pregnancy include:

  • loss of the pregnancy
  • birth defects affecting the baby’s heart (congenital heart disease)
  • a rare condition in newborns called pulmonary hypertension, where the blood pressure inside the lungs is abnormally high, causing breathing difficulties

However, there's no hard evidence that antidepressants cause these complications.

If you're pregnant and depressed, you should discuss the pros and cons of antidepressants with the doctor in charge of your care.

If antidepressants are recommended, they will usually be a type called a selective serotonin reuptake inhibitor (SSRI), such as fluoxetine.

Breastfeeding

As a precaution, the use of antidepressants if you're breastfeeding isn't usually recommended.

However, there are circumstances when both the benefits of treatment for depression (or other mental health conditions) and the benefits of breastfeeding your baby outweigh the potential risks.

If you're treated with antidepressants when breastfeeding, then paroxetine or sertraline is normally recommended.

Children and young people

The use of antidepressants isn't usually recommended in children and young people under the age of 18. This is because there's evidence that, in rare cases, they can trigger thoughts about suicide and acts of self-harm in this age group.

Concerns have also been raised that their use could affect the development of the brain in children and young people.

An exception can usually only be made if the following points are met:

  • the person being treated has failed to respond to talking therapies such as cognitive behavioural therapy, and
  • the person being treated will continue to receive talking therapies in combination with antidepressants, and
  • the treatment is supervised by a psychiatrist (a doctor who specialises in treating mental health conditions)

If an antidepressant is recommended, then fluoxetine is usually the first choice.

Alcohol

You should be wary of drinking alcohol if you're taking antidepressants, as alcohol is itself a depressant and drinking alcohol can make your symptoms worse.

If you drink alcohol while taking types of antidepressants called tricyclic antidepressants (TCAs) or monoamine oxidase inhibitors (MAOIs), you may become drowsy and dizzy.

You're less likely to experience unpleasant or unpredictable effects if you drink alcohol while taking an SSRI or a serotonin-noradrenaline reuptake inhibitor (SNRI) antidepressant, but avoiding alcohol is often still recommended in these cases.

Illegal drugs

The use of illegal drugs isn't recommended if you're taking antidepressants, particularly if you've been prescribed a TCA. This is because they can cause unpredictable and unpleasant effects.

In particular, you should avoid taking:

  • cannabis – smoking cannabis while taking a TCA can make you feel very ill
  • amphetamines (speed)
  • cocaine
  • heroin
  • ketamine

As with alcohol, illegal drugs can make symptoms of depression or other mental health conditions worse.

Other antidepressants

You should never take two different types of antidepressants, such as an SSRI and a TCA, unless advised by the doctor in charge of your care. This is because taking certain combinations of antidepressants can make you feel very ill and can be life-threatening.

If a decision is taken to switch you from one type to another, the dosage of the first antidepressant will usually be gradually reduced before the second is administered.

St John’s Wort

St John’s Wort is a popular herbal remedy promoted for the treatment of depression.

While there's evidence of its effectiveness, many experts advise against its use, because the amount of active ingredient varies among individual brands and batches, making the effects unpredictable.

Taking St John's Wort with other medications, such as anticonvulsants, anticoagulants, antidepressants and the contraceptive pill, can also cause serious health problems.

You shouldn't take St John's Wort if you're pregnant or breastfeeding, as it's unclear whether it's safe.

Driving and operating machinery

Some antidepressants can cause dizziness, drowsiness and blurred vision, particularly when you first start taking them.

If you do experience these problems, you should avoid driving or using tools and machinery.

Cautions for specific antidepressants

SSRIs

SSRIs may not be suitable if you have:

  • bipolar disorder and you're in a manic phase (a period where you're extremely excitable), although they can be useful for depressive phases
  • a bleeding disorder, or if you're taking medicines that make it more likely you may bleed (such as warfarin)
  • type 1 diabetes and type 2 diabetes
  • epilepsy – SSRIs should only be taken if your epilepsy is well controlled, and the medication should be stopped if your epilepsy gets worse
  • kidney disease

SNRIs

SNRIs may not be suitable if you have a history of heart disease or you have poorly controlled high blood pressure.

TCAs

TCAs may not be suitable if you have:

  • a history of heart disease
  • recently had a heart attack
  • liver disease
  • an inherited blood disorder called porphyria
  • bipolar disorder
  • schizophrenia
  • a growth on your adrenal glands that is causing high blood pressure (pheochromocytoma)
  • an enlarged prostate gland 
  • narrow angle glaucoma – increased pressure in the eye
  • epilepsy

Page last reviewed: 14/10/2015

Next review due: 01/10/2018