Comtan Adverse Reactions

Very common undesirable effects found in double-blind, placebo controlled phase III studies are dyskinesia, nausea and abnormal urine (see as follows).
Common undesirable effects found in double-blind, placebo controlled phase III studies are diarrhoea, Parkinsonism aggravated, dizziness, abdominal pain, insomnia, dry mouth, fatigue, hallucinations, constipation, dystonia, increased sweating, hyperkinesia, headache, leg cramps, confusion, paroniria, fall, postural hypotension, vertigo and tremor.
Most of the undesirable effects caused by entacapone relate to the increased dopaminergic activity and occur most commonly at the beginning of treatment. Reduction of levodopa dosage may decrease the severity and frequency of these effects. The other major class of undesirable effects are gastrointestinal symptoms, including e.g. nausea, vomiting, abdominal pains, constipation and diarrhoea. Urine may be discoloured reddish-brown by entacapone, but this is a harmless phenomenon.
Usually undesirable effects caused by entacapone are mild to moderate. The most common undesirable effects leading to discontinuation of entacapone treatment have been gastrointestinal symptoms (e.g. diarrhoea, 2.5%) and dopaminergic symptoms (e.g. dyskinesias, 1.7%).
Dyskinesias (27%), nausea (11%), diarrhoea (8%), abdominal pain (7%) and dry mouth (4.2%) were reported significantly more often with entacapone than with placebo in clinical studies.
Some of the adverse reactions such as, dyskinesia, nausea, and abdominal pain, may be more common with the higher doses (1,400 to 2,000 mg per day) than with the lower doses of entacapone.
Slight decreases in haemoglobin, erythrocyte count and haematocrit have been reported during entacapone treatment. The underlying mechanism may involve decreased absorption of iron from the gastrointestinal tract. During long-term treatment (6 months) with entacapone a clinically significant decrease in haemoglobin has been observed in 1.5% of patients.
Rare reports of clinically significant increases in liver enzymes have been received.
The following adverse drug reactions, listed as follows in Table 2, have been accumulated both from clinical studies with entacapone and since the introduction of entacapone into the market.
Adverse reactions are ranked under headings of frequency, the most frequent first, using the following convention: Very common (≥1/10); common (≥1/100, <1/10); uncommon (≥1/1,000, <1/100); rare (≥1/10,000, <1/1,000); very rare (<1/10,000); not known (cannot be estimated from the available data, since no valid estimate can be derived from clinical trials or epidemiological studies. (See Table 2.)

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Entacapone used in combination with levodopa has been associated with isolated cases of excessive daytime somnolence and sudden sleep onset episodes (see Effects on the Ability to Drive and Use Machines under Precautions).
Isolated cases of neuroleptic malignant syndrome (NMS) have been reported especially following abrupt reduction or discontinuation of entacapone and other dopaminergic medications.
Isolated cases of rhabdomyolysis have been reported.
Impulse control disorders: pathological gambling, increased libido, hypersexuality, compulsive spending or buying, binge eating and compulsive eating can occur in patients treated with dopamine agonists and/or other dopaminergic treatments such as entacapone in association with levodopa (see Precautions).