Side effects

What are the common side effects of medication treatment?

Key Points:

  • Every treatment has advantages and disadvantages.
  • Some people worry about side effects so much that they avoid taking treatments that could really help.
  • Keep in mind that a wide range of medicines are used in health care, with many beneficial effects and limited problems with side effects.
  • The following section below has detailed information about the side effects of medicines commonly used for depression: early side effects, longer term side effects, and uncommon but serious side effects.

What are the common side effects of medication treatment?

When considering treatment, many people want to know about possible side effects.

If you look at the possible side effects of commonly used medicine such as Aspirin or Tylenol, the list of potential side effects is long and worrying. However, most people are able to take these medicines without problems or side effects.

Still, it is helpful to have information about possible side effects when considering medication treatment.

  • Side effects vary depending on the medicine, its dose, how long you take it, and how quickly the dose is increased or decreased.
  • Other factors such as age, sex, health, and the use of other medicines can also influence side effects.
  • Side effects are one factor that doctors and patients consider in choosing the best medicine.
  • The side effects that are most important vary depending on the person.
  • The information provided here is general in nature. More specific information is available from your doctor or pharmacist.
  • When you are considering a medicine, you may ask your doctor about beneficial effects and side effects.
  • When you fill a prescription, you often get a print out from the pharmacy.  At times this information may list possible side effects without saying how many people have them.  If you are concerned about any information in the print out, be sure to discuss this with your doctor or pharmacist.

Early side effects:

  • Some side effects may start shortly after starting a medicine.  Many of these may decrease or stop after you have been taking the medicine for a few weeks.
  • Others may go away only when you stop taking the medicine or reduce the dosage.
  • If you are concerned about side effects, it is helpful to discuss this with your doctor.  If you have problems with a side effect, your doctor can suggest ways to manage this.
  • About 6 out of 10 people will experience at least one side effect.  Most people do not need to stop because of side effects.
  • Common early side effects of the most widely-used medicines for depression are shown in the two tables at the link below.
  • Your doctor or pharmacist will have information about other medicines used for depression that may not be in the tables.

Table of early side effects of common medicines for depression

Read More - Common side effects

Long-term side effects

Two longer-term side effects are common with medicines for depression: sexual problems and weight gain. These are more of a problem with some medicines than others.

Sexual side effects:

  • Men and women often have a reduction in sexual functioning when they are depressed (before treatment).
  • Reduced sexual function in men and women is also a side effect of many medicines for depression. Sexual interest, ability to become aroused and ability to have an orgasm may be affected.  When the medicine is stopped sexual functioning returns to normal.
  • At least 2 out of 10 people who take medicines for depression report sexual side effects. More problems with sexual side effects are reported with paroxetine (Paxil), while fewer problems are reported with bupropion (Wellbutrin).
  • Be sure to talk to your doctor if you are concerned about these side effects.  Your doctor may be able to suggest ways of managing them.  Don’t let embarrassment stop you from asking these questions.  Your doctor will be familiar with these concerns.

Weight gain:

  • For many medicines for depression, weight gain comes later in treatment.
  • There may even be weight loss early in treatment, then weight gain later in treatment.
  • More problems with weight gain are reported with mirtazapine (Remeron) and paroxetine (Paxil) than most of the other medicines in this group. Fewer problems are reported with bupropion (Wellbutrin).
  • The amount of weight gain is quite limited on average for most of the antidepressant medicines, in the range of 1 or 2 pounds (0.5 to 1.0 kg) over a year.  Within this average some persons gain more weight and some persons lose weight.
  • If you are concerned about weight gain, be sure to discuss this with your family doctor.


Clayton, A.H., & Montejo, A.L. (2006). Major depressive disorder, antidepressants, and sexual dysfunction. Journal of Clinical Psychiatry, 67(6), 33-37.

Gartlehner G, Hansen RA, Morgan LC, Thaler K, Lux LJ, Van Noord M, Mager U, Gaynes BN, Thieda P, Strobelberger M, Lloyd S, Reichenpfader U, Lohr KN. Second-Generation Antidepressants in the Pharmacologic Treatment of Adult Depression: An Update of the 2007 Comparative Effectiveness Review.  AHRQ Publication

No. 12-EHC012-EF. Rockville, MD: Agency for Healthcare Research and Quality. December 2011.

Kennedy, S. H., & Rizvi, S. (2009). Sexual dysfunction, depression, and the impact of antidepressants. Journal of Clinical Psychopharmacology, 29(2), 157-164.

Lam, R.W., Kennedy, S.H., Grigoriadis, S., McIntyre, R.S., Milev, R., Ramasubbu, R., Parikh, S.V., Patten, S.B., & Ravindran, A.V.  (2009). Canadian Network for Mood and Anxiety Treatments (CANMAT) clinical guidelines for the management of major depressive disorder in adults. III. Pharmacotherapy.  Journal of Affective Disorders, 117 (Suppl 1),S26-S43. doi: 10.1016/j.jad.2009.06.041

Serretti, A., & Mandelli, L. (2010). Antidepressants and body weight: A comprehensive review and meta-analysis. Journal of Clinical Psychiatry, 71(10), 1259-1272.

Zimmerman, M., Posternak, M. A., Attiullah, N., Friedman, M., Boland, R. J., Baymiller, S., . . . Chelminski, I. (2005). Why isn’t bupropion the most frequently prescribed antidepressant? Journal of Clinical Psychiatry, 66(5), 603-610.

Read More - Longer term side effects

Uncommon but serious side effects

1. Drug Interactions: Serious effects may occur if you take a medication for depression with other medicines.

  • It is important to tell your doctor all of the medicines you are taking, including any herbal or natural medicines (such as St. John’s Wort or tryptophan).
  • If you consider starting another medicine, tell the doctor before starting it to see if there are possible drug interactions with the new medicine.
  • Medicines that may interact include some other prescription medicines for depression, migraine headaches, pain, and some over-the-counter cough medicines.
  • Your doctor or a pharmacist can provide information about drug interactions.

2. Suicidal thoughts: Persons with depression sometimes experience thoughts of suicide.

  • Medication treatment reduces the rate of suicidal thoughts, suicide attempts, and completed suicide among persons with depression.
  • A small number of people (around 4 out of 100) start to have thoughts of suicide when they start a medicine for depression.
  • If you have problems with thoughts of suicide, be sure to talk to your doctor about this right away.

3. Very high mood:

  • Occasionally, people who take a medicine for depression can experience a sudden change in their mood. The depression may be replaced by a feeling of higher than normal energy, with rapid thoughts and higher than normal mood or much increased irritability.
  • There may also be a great reduction in the need for sleep.
  • If this change occurs, you should contact your doctor as soon as possible so they can assess the situation and change the treatment if necessary.
  • People with higher than normal mood may make decisions and take actions that can be harmful to themselves and the people around them.

4. Alcohol:  

  • When you are taking these medicines, it is a good idea to avoid using alcohol or to use very little.
  • Heavy alcohol use is a risk factor for anxiety and depression.
  • The use of any alcohol reduces the ability to drive safely and when mixed with medicines for depression the risk of unsafe driving is higher.
  • It is also best to avoid the use of drugs (such as marijuana).

5. Allergic reaction: There is a small chance of an allergic response to any new medicine. Common symptoms include a skin rash. If this happens, speak to your doctor before taking any more of the medicine.

Medication treatment


Barbui, C., Esposito, E., & Cipriani, A. (2009). Selective serotonin reuptake inhibitors and risk of suicide: A systematic review of observational studies. Canadian Medical Association Journal, 180(3), 291-297.

Dudley, M., Goldney, R., & Hadzi-Pavlovic, D. (2010). Are adolescents dying by suicide taking SSRI antidepressants? A review of observational studies. Australasian Psychiatry, 18(3), 242-245.

Stone, M., Laughren, T., Jones, M. L., Levenson, M., Holland, P. C., Hughes, A., . . . Rochester, G. (2009). Risk of suicidality in clinical trials of antidepressants in adults: Analysis of proprietary data submitted to US food and drug administration. BMJ: British Medical Journal, 339(7718)

Vitiello, B., Silva, S. G., Rohde, P., Kratochvil, C. J., Kennard, B. D., Reinecke, M. A., . . . March, J. S. (2009). Suicidal events in the treatment for adolescents with depression study (TADS). Journal of Clinical Psychiatry, 70(5), 741-747.

Read More - Uncommon but serious side effects

Please See:

What happens when the medicine is gradually reduced and eventually stopped?

How long should you keep taking the medicine?

How long does it take for the medicine to work?

Table of early side effects of common medicines for depression

Cost of medication

Combining medication and therapy

Download: Fact Sheet: Medication Side Effects on our Fact Sheets web page.