Like all medicines, this medicine can cause side effects, although not everybody gets them. No additional side effects were observed in children and adolescents compared to adults.
Very common (may affect more than 1 in 10 people): nausea, constipation, dizziness, drowsiness, headache.
Common (may affect up to 1 in 10 people): decreased appetite, anxiety, depressed mood, sleep problem, nervousness, restlessness, disturbance in attention, trembling, muscle twitches, flushing, shortness of breath, vomiting, diarrhoea, indigestion, itching, increased sweating, rash, feeling of weakness, fatigue, feeling of body temperature change, mucosal dryness, accumulation of water in the tissue (oedema).
Uncommon (may affect up to 1 in 100 people): allergic reaction to medicines (including swelling beneath the skin, hives, and in severe cases difficulty breathing, a fall in blood pressure, collapse, or shock),weight loss, disorientation, confusion, excitability (agitation), perception disturbances, abnormal dreams, euphoric mood, depressed level of consciousness, memory impairment, mental impairment, fainting, sedation, balance disorder, difficulty in speaking, numbness, abnormal sensations of the skin (e.g. tingling, prickling), abnormal vision, faster heartbeat, slower heartbeat, palpitations, decreased blood pressure, abdominal discomfort, hives, delay in passing urine, frequent urination, sexual dysfunction, drug withdrawal syndrome (see ‘If you stop taking PALEXIA SR’), feeling abnormal, irritability.
Rare (may affect up to 1 in 1,000 people): drug dependence, thinking abnormal, epileptic fits, near fainting, coordination abnormal, dangerously slow or shallow breathing (respiratory depression), impaired gastric emptying, feeling drunk, feeling of relaxation.
Not known (frequency cannot be estimated from the available data): Delirium.
In general, the likelihood of having suicidal thoughts and behaviour is increased in patients suffering from chronic pain. In addition, certain medicines for the treatment of depression (which have an impact on the neurotransmitter system in the brain) may increase this risk, especially at the beginning of treatment. Although tapentadol also affects neurotransmitters, data from human use of tapentadol do not provide evidence for an increased risk.