PK-Merz Special Precautions

An ECG (50 mm/s) should be recorded before and 1 and 3 weeks after commencing treatment and the Bazett frequency-corrected QT time (QTc) determined manually. Such an ECG should also be recorded before and 2 weeks after any subsequent increase in dose. Further ECG check-ups should then take place at least once a year. Treatment must be avoided or discontinued in patients who show baseline QTc values above 420 ms, an increase in QTc of more than 60 ms during treatment with Amantadine Sulphate (PK-Merz) 100 mg film-coated tablets, or a QTc time in excess of 480 ms during treatment with Amantadine Sulphate (PK-Merz) 100 mg film-coated tablets, and in patients who show discernible U waves.
Patients at risk of electrolyte imbalances, owing e.g. to treatment with diuretics, frequent vomiting and/or diarrhea, use of insulin in emergency situations or renal or anorectic conditions must undergo adequate monitoring of laboratory parameters and appropriate electrolyte replacement, particularly for potassium and magnesium.
In the event of symptoms such as palpitations, dizziness or syncope, treatment with Amantadine Sulphate (PK-Merz) 100 mg film-coated tablets must be immediately discontinued and the patient checked within 24 hours for QT prolongation. If no QT prolongation is present, treatment with Amantadine Sulphate (PK-Merz) 100 mg film-coated tablets can be recommenced, taking into account the contraindications and interactions.
In the case of patients with cardiac pacemakers, exact determination of QT times is not possible, therefore the decision on use of Amantadine Sulphate (PK-Merz) 100 mg film-coated tablets must be made on an individual basis in consultation with the patient's cardiologist.
Supplementary administration of amantadine for the prevention and treatment of influenza virus A infection is inadvisable and should be avoided on account of the danger of overdose.
Yellow-orange S (E 110) can trigger allergic reactions.
Lactose: Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.
Effects on ability to drive and use machines: Effects on vigilance and accommodation, particularly in association with the effects of other drugs used to treat parkinsonian syndromes, cannot be ruled out. At the beginning of treatment there may consequently be a further deterioration in the ability to drive and operate machinery over and above any impairment caused by the condition itself.
This impairment is further intensified in combination with alcohol.