The most frequently reported events were in the central nervous system and gastrointestinal system.
The most common reported events were nausea, dizziness and somnolence.
In addition, the following effects have been frequently observed, though the frequency is generally lower:
Body as a Whole: Asthenia, fatigue, hot flushes.
Central and Peripheral Nervous System: Headache, tremor.
Gastrointestinal System: Abdominal pain, constipation, diarrhea, dyspepsia, flatulence, dry mouth, vomiting.
Psychiatric Disorders: Anorexia, anxiety, confusion, euphoria, insomnia, nervousness.
Skin and Appendages: Pruritus, rash, increased sweating.
Uncommon reported clinically significant adverse experiences with at least a possible causal link to Ultracet include:
Body as a Whole: Chest pain, rigors, syncope, withdrawal syndrome.
Cardiovascular Disorders: Hypertension, aggravated hypertension, hypotension.
Central and Peripheral Nervous System: Ataxia, convulsions, hypertonia, migraine, aggravated migraine, involuntary muscle contractions, paraesthesia, stupor, vertigo.
Gastrointestinal System: Dysphagia, melena, tongue edema.
Hearing and Vestibular Disorders: Tinnitus.
Heart Rate and Rhythm Disorders: Arrhythmia, palpitation, tachycardia.
Liver and Biliary System: Liver test abnormalities.
Metabolic and Nutritional Disorders: Decreased weight.
Psychiatric Disorders: Amnesia, depersonalization, depression, drug abuse, emotional lability, hallucination, impotence, bad dreams, abnormal thinking.
Red Blood Cell Disorders: Anemia.
Respiratory System: Dyspnea.
Urinary System: Albuminuria, micturition disorder, oliguria, urinary retention.
Vision Disorders: Abnormal vision.
Other clinically significant adverse experiences previously reported in clinical trials or post-marketing reports with tramadol HCl: Other events which have been reported with the use of tramadol products include: Orthostatic hypotension, allergic reactions (including anaphylaxis and urticaria, Stevens-Johnson syndrome/TENS), cognitive dysfunction, suicidal tendency and hepatitis. Reported laboratory abnormalities included elevated creatinine. Serotonin syndrome (whose symptoms may include fever, excitation, shivering and agitation) has been reported with tramadol when used concomitantly with other serotonergic agents eg, SSRIs and MAO inhibitors. Post-marketing surveillance of tramadol has revealed rare alterations of warfarin effect, including elevation of prothrombin times.
Other clinically significant adverse experiences previously reported in clinical trials or post-marketing reports with paracetamol: Allergic reactions (primarily skin rash) or reports of hypersensitivity secondary to paracetamol are rare and generally controlled by discontinuation of the drug, and when necessary, symptomatic treatment. There have been several reports that suggest that paracetamol may produce hypoprothrombinemia when administered with warfarin-like compounds. In other studies, prothrombin time did not change.