Symmetrel (Amantadine Hydrochloride) - Side Effects and Adverse Reactions

ADVERSE REACTIONS

The adverse reactions reported most frequently at the recommended dose of SYMMETREL (5-10%) are: nausea, dizziness (lightheadedness), and insomnia.

Less frequently (1-5%) reported adverse reactions are: depression, anxiety and irritability, hallucinations, confusion, anorexia, dry mouth, constipation, ataxia, livedo reticularis, peripheral edema, orthostatic hypotension, headache, somnolence, nervousness, dream abnormality, agitation, dry nose, diarrhea and fatigue.

Infrequently (0.1-1%) occurring adverse reactions are: congestive heart failure, psychosis, urinary retention, dyspnea, skin rash, vomiting, weakness, slurred speech, euphoria, thinking abnormality, amnesia, hyperkinesia, hypertension, decreased libido, and visual disturbance, including punctate subepithelial or other corneal opacity, corneal edema, decreased visual acuity, sensitivity to light, and optic nerve palsy.

Rare (less than 0.1%) occurring adverse reactions are: instances of convulsion, leukopenia, neutropenia, eczematoid dermatitis, oculogyric episodes, suicidal attempt, suicide, and suicidal ideation (see WARNINGS).

Other adverse reactions reported during postmarketing experience with SYMMETREL usage include:

Nervous System/Psychiatric
coma, stupor, delirium, hypokinesia, hypertonia, delusions, aggressive behavior, paranoid reaction, manic reaction, involuntary muscle contractions, gait abnormalities, paresthesia, EEG changes, and tremor. Abrupt discontinuation may also precipitate delirium, agitation, delusions, hallucinations, paranoid reaction, stupor, anxiety, depression and slurred speech;

Cardiovascular
cardiac arrest, arrhythmias including malignant arrhythmias, hypotension, and tachycardia;
Respiratory
acute respiratory failure, pulmonary edema, and tachypnea;
Gastrointestinal
dysphagia;
Hematologic
leukocytosis; agranulocytosis
Special Senses
keratitis and mydriasis;
Skin and Appendages
pruritus and diaphoresis;
Miscellaneous
neuroleptic malignant syndrome (see WARNINGS), allergic reactions including anaphylactic reactions, edema, fever, pathological gambling, increased libido including hypersexuality, and impulse control symptoms.
Laboratory Test
elevated: CPK, BUN, serum creatinine, alkaline phosphatase, LDH, bilirubin, GGT, SGOT, and SGPT.

REPORTS OF SIDE EFFECTS / ADVERSE REACTIONS RELATED TO SYMMETREL

Possible Symmetrel side effects / adverse reactions in 67 year old female

Reported by a individual with unspecified qualification from Japan on 2007-02-13

Patient: 67 year old female weighing 51.0 kg (112.2 pounds)

Reactions: Autonomic Nervous System Imbalance, Head Injury, Drug Interaction, Cerebral Atrophy, Torticollis, Parkinsonism, Fall, Constipation, Cerebellar Atrophy, Dysstasia, Micturition Disorder

Adverse event resulted in: hospitalization

Suspect drug(s):
Carbidopa
    Administration route: Oral
    Start date: 1995-01-01
    End date: 1995-01-01

Levodopa W/benserazide/
    Administration route: Oral
    Indication: Parkinsonism
    Start date: 1995-01-01
    End date: 1995-01-01

Parlodel
    Dosage: 2.5 mg, qd
    Administration route: Oral
    Indication: Parkinsonism
    Start date: 1995-11-01
    End date: 1996-03-05

Parlodel
    Dosage: 2.5 mg, bid
    Administration route: Oral
    Start date: 1996-03-06
    End date: 1996-07-10

Symmetrel
    Dosage: 50 mg, bid
    Administration route: Oral
    Indication: Parkinsonism
    Start date: 1995-12-06
    End date: 1996-07-10

Talipexole
    Administration route: Oral
    Start date: 1995-01-01
    End date: 1995-01-01

Trihexyphenidyl Hydrochloride
    Dosage: 2 mg, qd
    Administration route: Oral
    Indication: Parkinsonism
    Start date: 1996-04-10
    End date: 2004-06-18

Other drugs received by patient: Neodopasol

Possible Symmetrel side effects / adverse reactions in 67 year old female

Reported by a individual with unspecified qualification from Japan on 2007-02-23

Patient: 67 year old female weighing 51.0 kg (112.2 pounds)

Reactions: Weight Decreased, Contusion, Head Injury, Urinary Incontinence, Drug Interaction, Parkinsonism, Fall, Constipation, Cardiomegaly, Cerebellar Atrophy, Hypokinesia, Neck Pain, Blood Cholesterol Increased, Urinary Retention, Autonomic Nervous System Imbalance, Torticollis, Dysstasia, Syncope, Gait Disturbance, Blood Pressure Decreased

Adverse event resulted in: hospitalization

Suspect drug(s):
Carbidopa
    Administration route: Oral
    Start date: 1995-01-01
    End date: 1995-01-01

Carbidopa
    Dosage: 200 mg/day
    Start date: 2006-10-26

Levodopa W/benserazide/
    Dosage: 200 mg/day
    Administration route: Oral
    Indication: Parkinsonism
    Start date: 1995-01-01
    End date: 1995-01-01

Parlodel
    Dosage: 2.5 mg, qd
    Administration route: Oral
    Indication: Parkinsonism
    Start date: 1995-11-01
    End date: 1996-03-05

Parlodel
    Dosage: 2.5 mg, bid
    Administration route: Oral
    Start date: 1996-03-06
    End date: 1996-07-10

Symmetrel
    Dosage: 50 mg, bid
    Administration route: Oral
    Indication: Parkinsonism
    Start date: 1995-12-06
    End date: 1996-07-10

Talipexole
    Dosage: 2.0 mg/day
    Administration route: Oral
    Start date: 1995-01-01
    End date: 1995-01-01

Talipexole
    Dosage: 2.6 mg/day
    Start date: 1996-10-24

Trihexyphenidyl Hydrochloride
    Dosage: 2 mg, qd
    Administration route: Oral
    Indication: Parkinsonism
    Start date: 1996-04-10
    End date: 2004-06-18

Other drugs received by patient: Distigmine Bromide; Neodopasol

Possible Symmetrel side effects / adverse reactions in 74 year old male

Reported by a consumer/non-health professional from South Africa on 2007-03-01

Patient: 74 year old male

Reactions: Cardiac Discomfort, Angina Pectoris, Prescribed Overdose, Blood Pressure Decreased, Feeling Abnormal

Adverse event resulted in: hospitalization

Suspect drug(s):
Parlodel
    Dosage: 2.5 mg, tid
    Administration route: Oral
    Indication: Parkinson's Disease
    Start date: 2007-02-14
    End date: 2007-02-16

Symmetrel
    Dosage: 200 mg, qd
    Administration route: Oral
    Indication: Parkinson's Disease
    Start date: 2007-02-14
    End date: 2007-02-16

Other drugs received by patient: Carbilev