Medication resource centre



A rare, but serious side effect that can occur with some antipsychotic medication. It involves a large drop in white blood cells and puts an individual at increased risk of infection. The drop in white blood cells cannot be felt by the individual and this is the reason why blood may be checked closely in individuals taking antipsychotic medications. By checking blood often, healthcare providers can see if an individual has had a drop in white blood cell counts and inform them before the individual develops infection.


A potential side effect of many antipsychotic medications. Individuals with akathisia feel an unpleasant sensation of inner restlessness. It is often visible in individuals as frequent moving, inability to sit still, crossing and uncrossing legs, pacing and feelings of anxiety or panic.


An arrhythmia is a condition in which the heart beats with an irregular or abnormal rhythm. Some antipsychotic medications can increase the risk of arrhythmia. This side effect can be very serious so your doctor will review your heart health with you and may do tests to look at your heart rhythm in some cases.

Brand-Name Medication

A medication that is discovered and sold by a pharmaceutical company under a patent for many years. Brand-name medication is more expensive than generic medication because the pharmaceutical company who discovered it has many costs with the medication research and marketing. A brand-name medication is given a brand/trade name by the pharmaceutical company which can only be used by the original company.


This is a potential side effect with many antipsychotic medications. It is a side effect that decreases the number of bowel movements an individual has to less than 3 per week or results in bowel movements that are very hard, dry and difficult to pass. If you notice any change to your bowel routine on antipsychotic medication it is very important to tell your doctor and pharmacist.

Depot Injection

This is a type of long-acting intramuscular injection. Some antipsychotic medications are formulated into depot injections so that individuals can take medication less often. Most depot injections need to be given every 2 - 4 weeks.


Some antipsychotic medications can cause individuals to feel drowsy or very sleepy. Often this side effect improves the longer you are on the medication.

Extrapyramidal Symptoms

A potential side effect of antipsychotic medication due to blocking of dopamine in different parts of the brain. These side effects impact movement. They include things like muscle stiffness, restlessness, tremors, involuntary movements of tongue, fingers, feet and stiffness or rigidity.

Generic Medication

A copy of a brand-name medication. It is equivalent to the brand-name medication in terms of safety and efficacy but may be a different shape or a different colour. It is sold for less money, after the patent on the original brand-name medication expires.


This is a potential side effect associated with antipsychotic medication. It is more common with typical antipsychotics but it can occur with some of the atypical medications. It means that individuals get an increased level of prolactin in their body because the medication blocks dopamine receptors. Prolactin is a hormone involved in things like menstrual cycles, sexual desire and function and production of breast milk. Individuals who have this side effect may experience loss of interest in sex, change in menstrual cycle (including no longer experiencing a monthly period), premature ejaculation and swelling of breasts and production of breast milk in males and females (who are not pregnant and/or have not given birth recently).


Some individuals may experience insomnia with antipsychotic medication. This means that individuals may have trouble falling asleep and/or staying asleep. The medication may make them feel very awake. If this happens to you it is best to try taking the medication in the morning to help prevent sleeping difficulties at bed time.

Neuroleptic Malignant Syndrome

This is a very rare side effect that may occur with antipsychotic treatment. This side effect can be life-threatening. It usually consists of fever, confusion, stiffness of the muscles and changes to the nervous system leading to wide swings of blood pressure, excessive sweating and excessive secretion of saliva.

Orthostatic Hypotension

This is a side effect that can occur with many antipsychotic medications. It is when an individual experiences a drop in their blood pressure reading when they stand up. In order to decrease the risk of this side effect it is important to stand up slowly from sitting positions or when you are lying down. If a person has this side effect they may feel dizzy or they may faint when they stand up quickly.


A type of extrapyramidal side effect or movement side effect that may occur with antipsychotic medication. It is called Parkinsonism because it looks similar to symptoms that individuals with Parkinson’s disease may have. The common things you will see in individuals who get this side effect from antipsychotic medication are hand tremor/shaking, slow movement, slow speech/talking and muscle stiffness.

Sublingual Tablet

A sublingual tablet is one that must be dissolved in the mouth instead of swallowed. These medications dissolve easily in saliva under your tongue.

Tardive Dyskinesia

This is a potential side effect of antipsychotic treatment. It occurs most often with typical antipsychotic medications. It usually occurs after being treated for long periods of time and/or being treated with high doses of the medication. It involves involuntary, repetitive movements of the body. It often involves things like lip smacking, tongue movements, a lot of eye blinking, repeated tongue movements and lip pursing/puckering. You can sometimes also see involuntary movements in the arms and legs, fingers and in the chest area.