Explain possible side effects and interaction/safety considerations for melatonin without overstating causality or efficacy.
Source
Clinical statements on this page are taken from the SAHPRA-approved patient information leaflet (approved 30/10/2024) and professional information (approved 30/10/2024) for this product: patient information leaflet, professional information. Retrieved 2026-09-03. Where this page and the approved leaflet differ, the leaflet is correct.
What is melatonin?
Which leaflet this comes from
There is no approved leaflet for Melatonin in SAHPRA’s public repository. The information below is from the approved leaflet for Cadiatev, another South African product containing Melatonin. Products with the same active ingredient can still differ in strength, formulation and approved uses, so check the leaflet in your own pack.
Melatonin contains the active ingredient Melatonin.
- Active ingredient — Melatonin
- Registration number — 56/2.2/0389
- Registration holder — Teva Pharmaceuticals (Pty) Ltd
It is approved for:
- The active substance of CADIATEV, melatonin, belongs to a natural group of hormones produced by the body
- S4 CADIATEV is used on its own for the short-term (up to 13 weeks) treatment of primary insomnia (persistent difficulty in getting to sleep or staying asleep, or poor quality of sleep) in patients aged 55 years and older
- ‘Primary’ means that the insomnia does not have any identified cause, including any medical, mental, or environmental cause
Possible side effects of melatonin
Not everyone gets side effects. The effects below are those listed in the South African approved leaflet, grouped using the leaflet’s own frequency wording.
About these frequency terms
This leaflet groups effects as “Frequent” and “Less frequent” rather than the very common/common/uncommon scale used in some other markets.
Less frequent side effects
- a reactivation of the chickenpox virus in the body, causing a painful rash
- reduced number of white blood cells in the blood
- reduced blood platelets, which increases risk of bleeding or bruising
- a high level of a certain type of fat (triglycerides) in the blood
- low serum calcium levels in the blood, low sodium levels in the blood
- irritability, nervousness, restlessness, insomnia, abnormal dreams, nightmares, anxiety, migraine, headache
- altered mood, aggression, agitation, crying, stress symptoms, early morning awakening, increased sex drive, depressed mood, depression
- restlessness associated with increased activity, dizziness, tiredness, disturbance in attention, memory impairment
- lethargy (tiredness, lack of energy), restless legs syndrome, poor quality sleep, ‘pins and needles’ feeling, migraine, fainting
- feeling of drowsiness
- visual impairment, excessive tearing
- blurred vision
- vertigo (a feeling of dizziness or ‘spinning’), episodes of dizziness and a sensation of spinning with certain head movements
- high blood pressure, hot flushes
- upper abdominal pain, stomach pain, indigestion, mouth ulceration, dry mouth, nausea
- acid reflux, stomach disorder, inflammation of the stomach lining
- blistering in the mouth, tongue ulceration, stomach upset, vomiting, abnormal bowel sounds, wind, excess saliva production, bad breath, abdominal discomfort, gastric disorder
- abnormal liver function, increased liver enzyme functions, abnormal increase of bilirubin in the blood
- eczema, skin rash, hand dermatitis, itchy rash, nail disorder, psoriasis, night sweats, itching, rash, dry skin, excessive sweating
- presence of red blood cells in the urine
- excretion of glucose in the urine
- excess proteins in the urine, passing large volumes of urine, urinating during the night
- pain in extremities, arthritis, muscle spasms, neck pain, night cramps
- menopausal symptoms
- prolonged erection that might be painful, inflammation of the prostate gland
- feeling of weakness, tiredness, pain, thirst
- changes in the composition of your blood which could cause yellowing of the skin or eyes, inflammation of the skin
- weight increase
- abnormal blood electrolytes. Side effects with unknown frequency:
- swelling of mouth or tongue, swelling of the skin
- abnormal milk secretion
Interactions and medicines to check
The approved leaflet names these interactions.
- Always tell your healthcare provider if you are taking any other medicine
- (This includes all complementary or traditional medicines.) Fluvoxamine (used for the treatment of depression and obsessive-compulsive disorder), psoralens (used in the treatment of skin disorders e.g., psoriasis), cimetidine (used in the treatment of stomach problems such as ulcers), quinolones and rifampicin (used in the treatment of bacterial infections), oestrogens (used in contraceptives or hormone replacement therapy) and carbamazepine (used in the treatment of epilepsy)
- Adrenergic agonists/antagonists (such as certain types of medicines used to control blood pressure by constricting blood vessels, nasal decongestants, blood pressure lowering medicines), opiate agonists/antagonists (such as medicines used in the treatment of drug addiction), prostaglandin inhibitors (such as nonsteroidal anti-inflammatory medicines), antidepressant medication, tryptophan, and alcohol
- Benzodiazepines and non-benzodiazepine hypnotics (medicines used to induce sleep such as zaleplon, zolpidem and zopiclone)
- Thioridazine (for the treatment of schizophrenia) and imipramine (for the treatment of depression)
- CADIATEV with food, drink, and alcohol: Take CADIATEV after you have eaten
- Do not drink alcohol before, during or after taking CADIATEV, because it reduces the effectiveness of CADIATEV
Bring the actual products to the conversation
A pharmacist can check for interactions much faster from the packaging than from remembered names.
Who should use extra caution?
The approved leaflet identifies the following cautions and factors.
Do not use it at all if
- if you are hypersensitive (allergic) to melatonin or to any other ingredients of CADIATEV (listed in section 6)
- if you are pregnant or breastfeeding
Use with care, and tell your doctor, if
- if you suffer from liver or kidney problems. No studies on the use of CADIATEV in people with liver or kidney diseases have been performed, you should speak to your doctor before taking CADIATEV as its use is not recommended
- if you have been told you suffer from an autoimmune disease (where the body is ‘attacked’ by its own immune system). No studies on the use of CADIATEV in people with auto-immune diseases have been performed; therefore, you should speak to your doctor before taking CADIATEV as its use is not recommended
- smoking may make CADIATEV less effective, because the components of tobacco smoke can increase the breakdown of melatonin by the liver. Children and adolescents: Do not give this medicine to children below 18 years as it has not been tested and its effects are unknown
Pregnancy and breastfeeding
- If you are pregnant or breastfeeding, think you may be pregnant or are planning to have a baby, please consult your doctor, pharmacist, or other healthcare provider for advice before taking CADIATEV
- Do not take CADIATEV if you are pregnant or breastfeeding your baby while taking CADIATEV
Dose, timing and other factors that can affect side effects
The approved leaflet identifies the following cautions and factors.
Do not use it at all if
- if you are hypersensitive (allergic) to melatonin or to any other ingredients of CADIATEV (listed in section 6)
- if you are pregnant or breastfeeding
Use with care, and tell your doctor, if
- if you suffer from liver or kidney problems. No studies on the use of CADIATEV in people with liver or kidney diseases have been performed, you should speak to your doctor before taking CADIATEV as its use is not recommended
- if you have been told you suffer from an autoimmune disease (where the body is ‘attacked’ by its own immune system). No studies on the use of CADIATEV in people with auto-immune diseases have been performed; therefore, you should speak to your doctor before taking CADIATEV as its use is not recommended
- smoking may make CADIATEV less effective, because the components of tobacco smoke can increase the breakdown of melatonin by the liver. Children and adolescents: Do not give this medicine to children below 18 years as it has not been tested and its effects are unknown
Pregnancy and breastfeeding
- If you are pregnant or breastfeeding, think you may be pregnant or are planning to have a baby, please consult your doctor, pharmacist, or other healthcare provider for advice before taking CADIATEV
- Do not take CADIATEV if you are pregnant or breastfeeding your baby while taking CADIATEV
Serious symptoms and warning signs
This leaflet does not set out a separate list of serious side effects. The general warning signs below apply to any medicine.
General warning signs that apply to any medicine
Call for emergency help now if any of these happen
- Difficulty breathing, wheezing, or tightness in the throat or chest
- Swelling of the face, lips, tongue or throat
- A widespread rash with blistering or peeling skin, or sores in the mouth, eyes or genitals
- Fainting, collapse, or a sudden severe drop in alertness
- Chest pain, or sudden weakness or numbness on one side of the body
- A fit (seizure), or confusion that comes on suddenly
In South Africa call 10177 for an ambulance, or 112 from a mobile phone. Go to your nearest emergency department if it is faster. Do not wait to see whether the symptom settles.
What to do if side effects occur
If you think you are having a side effect, the response depends on how severe it is. Use the warning signs above first — if any of those apply, treat it as urgent.
If the symptom is severe or frightening
Get medical help immediately. Call 10177 for an ambulance, or 112 from a mobile phone, or go to the nearest emergency department. Take the product and its packaging with you if you can.
If the symptom is mild but bothering you
- Write down what the symptom is, when it started, and how it relates to when you take the product
- Check the leaflet that came with the product to see whether the symptom is listed
- Speak to your pharmacist — for many questions this is the fastest route to a useful answer
- Contact the prescriber if the symptom is affecting your daily life or is not settling
Do not stop a prescribed treatment on your own
Stopping some treatments suddenly causes its own problems, and the condition being treated may get worse. If you want to stop, ask a pharmacist or doctor how to do it safely — they can usually offer an alternative.
You can also report a suspected side effect in South Africa. Reporting does not replace getting medical advice, and you do not need to be certain the product was the cause.
How to report a suspected side effect in South Africa
South Africa has an official system for reporting suspected side effects, run by the South African Health Products Regulatory Authority (SAHPRA). Reports from the public and from healthcare professionals are how safety signals get detected after a product is already in use.
Who can report
Anyone can report — you do not have to be a healthcare professional, and you do not need to prove that the product caused the problem. A suspicion is enough. Patients, caregivers and family members can all submit a report.
What to have ready
- The name of the product, its strength and form, and the batch number if you have it
- Why it was being used, and when it was started and stopped
- What the suspected reaction was, when it began, and how long it lasted
- Any other medicines, supplements or remedies being used at the same time
- Basic details about the person affected — age and sex are usually enough
How to report
SAHPRA accepts adverse reaction reports through its e-Services reporting system and through the Med Safety mobile app. Healthcare professionals can also report through the same routes. Current forms and access points are published on the SAHPRA site.
- SAHPRA Health Products Vigilance — the main vigilance and reporting hub
- SAHPRA e-Services — current adverse reaction reporting access
Reporting is not a substitute for medical care
If someone is unwell now, get medical help first and report afterwards. Urgent symptoms always take precedence over paperwork.
For a fuller walkthrough see how to report an adverse drug reaction.
Related pages
← Back to more supplement side effects.
Report a side effect
If you think you have had a side effect, you can report a suspected side effect in South Africa. Report a suspected side effect through the appropriate SAHPRA pathway where relevant.
Information only
This page gives general medicine-safety information for people in South Africa. It is not a diagnosis and not personalised medical advice. It cannot tell you whether a symptom you are having is caused by a particular product. Speak to a pharmacist or doctor about your own situation, and do not stop or change a prescribed treatment on the basis of a web page.
Editorial status: draft — not for publication
Brief SE-00216 · build rank 216 · Phase 2 · Tier 2. Every evidence slot on this page must be completed from the SAHPRA-approved source and the page signed off by a qualified clinical or pharmacy reviewer before it is published. Target length 1,300–2,000 words.