Yes. Drowsiness, sleepiness or feeling unusually tired can occur with some medicines used for depression, anxiety, sleep problems, bipolar disorder, schizophrenia and other mental health conditions. Some medicines are more sedating than others, and the effect can vary considerably from one person to another.
Drowsiness may be more noticeable when you first start a medicine, after a dose change, or when several medicines or substances with sedating effects are used together. However, feeling sleepy does not automatically mean that your mental health medicine is the cause. Poor sleep, depression, anxiety, other medical conditions and other medicines can also contribute to daytime sleepiness. MedlinePlus lists sleeping medicines, tranquillisers, antihistamines, certain pain medicines and some psychiatric medicines among possible causes of drowsiness.
If you are experiencing other symptoms as well, the Mental Health Medication Side Effects hub and our related parent guide can help you understand which effects may be worth discussing with a healthcare professional.
Important: Do not stop, reduce, increase or change the timing of a prescription mental health medicine without speaking to your doctor or pharmacist. If drowsiness is severe, worsening or interfering with driving, work or normal daily activities, get professional advice.
How mental Health Medication Causing Drowsiness can be linked to medicines or supplements
Medicines can cause drowsiness when they affect brain chemicals or nervous-system activity involved in alertness, sleep and relaxation. Depending on the medicine, this may feel like mild sleepiness, difficulty concentrating, slowed reactions, needing daytime naps or struggling to stay awake.
Antidepressants are one example. The NHS lists feeling dizzy, drowsy or very sleepy among possible antidepressant side effects, although individual medicines can affect sleep differently and some people experience insomnia instead.
Timing clues
The timing of your symptoms can provide useful information, although it cannot prove that a particular medicine is responsible.
Consider whether the drowsiness:
- began after starting a new medicine;
- became worse after your dose was changed;
- is strongest within a few hours of taking a dose;
- appeared after adding an over-the-counter medicine or supplement;
- becomes worse when alcohol is consumed;
- improves or worsens at a predictable time of day; or
- is accompanied by dizziness, poor balance, confusion or unusually slow reactions.
Some medicine side effects improve as the body adjusts. For example, NHS information on antidepressants notes that many side effects improve after a few weeks, although some can persist.
Persistent or disruptive drowsiness should still be discussed with your doctor or pharmacist rather than simply waiting for it to disappear.
Medicines and product categories that may be associated with this symptom
A number of mental health medicine categories can be associated with sleepiness. Not every medicine in a category affects every person in the same way, so always check the professional information or patient leaflet for your specific product.
Possible medicine categories
Antidepressants
Some antidepressants can cause drowsiness, dizziness or fatigue. Individual responses differ: one medicine may make a person sleepy while another may interfere with sleep. Sertraline and fluoxetine, for example, both list dizziness or drowsiness among possible side effects in current NHS information.
Do not suddenly stop an antidepressant because of sleepiness. Abrupt discontinuation can cause withdrawal symptoms, and a doctor may need to reduce the dose gradually when stopping is appropriate.
Antipsychotic medicines
Some antipsychotics can have sedating effects. Quetiapine, for example, may cause drowsiness, and MedlinePlus advises people taking it to avoid driving or operating machinery until they know how the medicine affects them. It also notes that alcohol can increase the drowsiness caused by quetiapine.
Medicines used for anxiety
Benzodiazepines and other sedating medicines used for anxiety can reduce alertness. The FDA notes that common effects of benzodiazepines include drowsiness and dizziness. Combining benzodiazepines with alcohol, opioids or other medicines that depress the central nervous system can substantially increase the risk of excessive sedation and breathing problems.
Sleep medicines and sedatives
Medicines intended to promote sleep can cause next-day drowsiness, problems concentrating and impaired driving or performance. Older adults may also face a greater risk of falls when sedating medicines affect balance or alertness.
Other medicines, supplements and products
Mental health medication may not be the only contributor. Certain antihistamines, pain medicines, sleeping products and other medicines can also cause drowsiness. Alcohol can add to the sedating effects of some prescription medicines.
Tell your pharmacist or doctor about all medicines and products you use, including prescription medicines, pharmacy medicines, vitamins, herbal products and supplements. This gives them a better chance of identifying combinations that may be contributing to your symptoms.
Red flags: when this symptom may need urgent medical attention
Mild sleepiness is not usually an emergency by itself. Severe drowsiness, however, can sometimes signal excessive medicine effects, a dangerous interaction or an overdose.
Red flags
Seek urgent medical attention if drowsiness occurs with:
- slowed, shallow or difficult breathing;
- extreme sleepiness where the person is difficult or impossible to wake;
- unusual confusion or severe disorientation;
- collapse or fainting;
- a seizure;
- blue or grey colouring of the lips or skin;
- severe swelling of the face, lips, tongue or throat;
- chest pain or another severe sudden symptom; or
- thoughts of suicide or self-harm.
Extreme sleepiness together with breathing difficulty or unresponsiveness is particularly concerning when sedating medicines have been combined. The FDA warns that benzodiazepines used with opioids or other central nervous-system depressants can result in extreme sleepiness, respiratory depression, coma and death.
If you suspect an overdose, someone has taken more medicine than prescribed, or a person cannot be properly awakened, seek emergency medical help immediately.
Drowsiness can also create an accident risk even when it is not medically severe. If a medicine is making you sleepy or dizzy, do not drive, operate machinery or perform another hazardous activity until you know it is safe to do so. This warning is specifically included in guidance for medicines such as sertraline, fluoxetine and quetiapine.
What to track before speaking to a doctor or pharmacist
Keeping a short record can make it easier for a healthcare professional to assess what may be happening.
What to track
Write down:
- the name and strength of each medicine you take;
- your prescribed dose;
- what time you take each dose;
- when the drowsiness first started;
- whether it followed a new prescription or dose change;
- what time of day the sleepiness is worst;
- how long the drowsiness lasts;
- how many hours you are sleeping at night;
- any other symptoms, such as dizziness, confusion or poor balance;
- any falls, near-falls or problems staying awake while driving or working;
- alcohol use;
- over-the-counter medicines, including allergy, cold or sleep products; and
- vitamins, herbal remedies and other supplements.
Also mention any other health changes that could affect sleep or alertness. Drowsiness can have causes unrelated to medication, including inadequate sleep and some underlying health conditions.
Take your medicine list and symptom notes to your doctor or pharmacist. They can review whether the timing fits a known side effect, whether another product could be contributing, and whether your treatment needs further assessment.
What not to do without medical advice
What not to change without advice
Do not stop a prescription mental health medicine suddenly simply because it makes you sleepy. Some medicines can cause significant withdrawal symptoms when stopped abruptly, while sudden changes may also affect the condition being treated.
You should also avoid changing the dose, splitting tablets, moving a dose from morning to evening, or taking it less frequently unless a healthcare professional has confirmed that this is appropriate for the particular medicine and formulation.
Do not try to compensate for medication-related drowsiness by taking additional stimulants, supplements or large amounts of caffeine without first checking whether they are suitable for you.
Be particularly careful about alcohol and other sedating substances. Alcohol can make the sleepiness or dizziness associated with some antidepressants and antipsychotics worse, while combining alcohol or other central nervous-system depressants with benzodiazepines can create more serious safety risks.
If your drowsiness is affecting your ability to work safely, drive, care for someone, study or complete normal daily activities, speak to your doctor or pharmacist rather than trying to manage the problem by changing your medicine yourself.
Related side-effect guides and reporting options in South Africa
Drowsiness can occur alongside other symptoms, so it may help to review our side effect symptoms A-Z or the broader guide to medication side effects.
If you think a medicine may be causing your symptoms, you can also discuss the reaction with your doctor or pharmacist. Keep the medicine packaging or leaflet available and provide details about when the symptoms started and any other products you were taking.
Suspected adverse drug reactions can be reported in South Africa. SAHPRA’s Med Safety system allows members of the public as well as healthcare professionals to report suspected adverse drug reactions, even when medicine causality has not been definitively established. You can learn more about how to report side effects in South Africa.
Drowsiness is a recognised possible effect of several types of mental health medicine, but how significant it is depends on the medicine, other substances being taken and the individual. If the symptom is persistent, worsening or interfering with daily life, speak to a doctor or pharmacist. If someone develops extreme sleepiness, cannot be awakened normally, has trouble breathing or develops another severe warning sign, seek emergency medical attention immediately.
This information is for general education and does not replace medical advice, diagnosis or treatment. Always discuss concerns about prescription medicines, side effects or interactions with a doctor or pharmacist.