The most commonly reported undesirable effects during the clinical trials performed with the paracetamol/tramadol combination were nausea, dizziness and somnolence, observed in more than 10% of the patients.
Cardiovascular system disorders: Uncommon: hypertension, palpitations, tachycardia, arrhythmia.
Central and peripheral nervous system disorders: Very common: dizziness, somnolence. Common: headache, trembling. Uncommon: involuntary muscular contractions, paraesthesia, tinnitus. Rare: ataxia, convulsions, syncope.
Psychiatric disorders: Common: confusion, mood changes (anxiety, nervousness, euphoria), sleep disorders. Uncommon: depression, hallucinations, nightmares, amnesia. Rare: drug dependence.
Vision disorders: Rare: blurred vision.
Respiratory system disorders: Uncommon: dyspnoea. Rare: Respiratory depression.
Gastrointestinal disorders: Very common: nausea. Common: vomiting, constipation, dry mouth, diarrhoea, abdominal pain, dyspepsia, flatulence. Uncommon: dysphagia, melaena.
Liver and biliary system disorders: Uncommon: hepatic transaminases increase.
Skin and appendages disorders: Common: sweating, pruritus. Uncommon: dermal reactions (e.g. rash, urticaria).
Body as a whole: Uncommon: shivers, hot flushes, thoracic pain.
Metabolism and nutrition disorders: Unknown: hypoglycaemia.
Post marketing surveillance: Very rare: abuse; Cutaneous hypersensitivity reactions including skin rashes, angioedema, Stevens-Johnson syndrome/Toxic Epidermal Necrolysis have been reported; Serotonin syndrome; Adrenal insufficiency; Androgen deficiency; Infertility.