Comtan (Entacapone) - Side Effects and Adverse Reactions

ADVERSE REACTIONS

During the pre-marketing development of entacapone, 1450 patients with Parkinson's Disease were treated with entacapone. Included were patients with fluctuating symptoms, as well as those with stable responses to levodopa therapy. All patients received concomitant treatment with levodopa preparations, however, and were similar in other clinical aspects.

The most commonly observed adverse events (>5%) in the double-blind, placebo-controlled trials (N=1003) associated with the use of Comtan (entacapone) and not seen at an equivalent frequency among the placebo-treated patients were: dyskinesia/hyperkinesia, nausea, urine discoloration, diarrhea, and abdominal pain.

Approximately 14% of the 603 patients given entacapone in the double-blind, placebo-controlled trials discontinued treatment due to adverse events compared to 9% of the 400 patients who received placebo. The most frequent causes of discontinuation in decreasing order are: psychiatric reasons (2% vs. 1%), diarrhea (2% vs. 0%), dyskinesia/hyperkinesia (2% vs. 1%), nausea (2% vs. 1%), abdominal pain (1% vs. 0%), and aggravation of Parkinson's Disease symptoms (1% vs. 1%).

ADVERSE EVENT INCIDENCE IN CONTROLLED CLINICAL STUDIES

Table 4 lists treatment emergent adverse events that occurred in at least 1% of patients treated with entacapone participating in the double-blind, placebo-controlled studies and that were numerically more common in the entacapone group, compared to placebo. In these studies, either entacapone or placebo was added to levodopa/carbidopa (or levodopa/benserazide).

The prescriber should be aware that these figures cannot be used to predict the incidence of adverse events in the course of usual medical practice where patient characteristics and other factors differ from those that prevailed in the clinical studies. Similarly, the cited frequencies cannot be compared with figures obtained from other clinical investigations involving different treatments, uses, and investigators. The cited figures do, however, provide the prescriber with some basis for estimating the relative contribution of drug and nondrug factors to the adverse events observed in the population studied.

EFFECTS OF GENDER AND AGE ON ADVERSE REACTIONS

No differences were noted in the rate of adverse events attributable to entacapone by age or gender.

DRUG ABUSE AND DEPENDENCE

Comtan (entacapone) is not a controlled substance. Animal studies to evaluate the drug abuse and potential dependence have not been conducted. Although clinical trials have not revealed any evidence of the potential for abuse, tolerance or physical dependence, systematic studies in humans designed to evaluate these effects have not been performed.

REPORTS OF SUSPECTED COMTAN SIDE EFFECTS / ADVERSE REACTIONS

Possible Comtan side effects / adverse reactions in 74 year old female

Reported by a pharmacist from Canada on 2011-10-03

Patient: 74 year old female weighing 65.0 kg (143.0 pounds)

Reactions: Blood Alkaline Phosphatase Increased, Gamma-Glutamyltransferase Increased, Crohn's Disease, Hypotension, Aspartate Aminotransferase Increased, Delirium

Adverse event resulted in: hospitalization

Suspect drug(s):
Comtan

Other drugs received by patient: Prednisone; Acetaminophen; Acetaminophen

Possible Comtan side effects / adverse reactions in 77 year old male

Reported by a pharmacist from Spain on 2011-10-03

Patient: 77 year old male

Reactions: Wrong Drug Administered, Depressed Level of Consciousness, Drug Interaction

Adverse event resulted in: life threatening event, hospitalization

Suspect drug(s):
Comtan

Other drugs received by patient possibly interacting with the suspect drug:
Clonazepam
    Dosage: 5 mg, unk
    Administration route: Oral
    Start date: 2011-07-01

Madopar
    Dosage: 375 mg, unk
    Administration route: Oral
    Start date: 2011-07-01

Seroquel XR
    Dosage: 400 mg, unk
    Start date: 2011-07-01

Possible Comtan side effects / adverse reactions in 77 year old male

Reported by a health professional (non-physician/pharmacist) from Spain on 2011-10-07

Patient: 77 year old male

Reactions: Wrong Drug Administered, Depressed Level of Consciousness

Adverse event resulted in: life threatening event

Suspect drug(s):
Clonazepam
    Dosage: start date : july 2011
    Administration route: Oral
    Indication: Product Used FOR Unknown Indication

Comtan
    Dosage: start date : july 2011
    Administration route: Oral
    Indication: Product Used FOR Unknown Indication

Madopar
    Dosage: start date : july 2011
    Administration route: Oral
    Indication: Product Used FOR Unknown Indication

Quetiapine Fumarate
    Dosage: start date : july 2011 , drug name seroquel prolong
    Administration route: Oral
    Indication: Product Used FOR Unknown Indication