Interactions : אינטראקציות

4.5 Interaction with other medicinal products and other forms of interaction
Caution should be exercised when the following drugs are administered concomitantly with Dopicar.
Antihypertensive agents
Postural hypotension can occur when Dopicar is added to the treatment of patients already receiving antihypertensive drugs. Dosage adjustment of the antihypertensive agent may be required.


Antidepressants

Rarely, reactions including hypertension and dyskinesia have been reported with the concomitant use of tricyclic antidepressants. (see first paragraph of section 4.3 'Contraindications' for patients receiving MAOIs).
Anticholinergics
Anticholinergics may affect the absorption and thus the patient’s response.
Iron
Studies demonstrate a decrease in the bioavailability of carbidopa and/or levodopa when it is ingested with ferrous sulphate or ferrous gluconate.
Other drugs
• To date there has been no indication of interactions that would preclude concurrent use of standard antiparkinsonian drugs.
• Dopamine D2 receptor antagonists (e.g. phenothiazines, butyrophenones, and risperidone) and isoniazid, may reduce the therapeutic effects of levodopa. The beneficial effects of levodopa in Parkinson’s disease have been reported to be reversed by phenytoin and papaverine. Patients taking these drugs with Dopicaer should be carefully observed for loss of therapeutic response.
• Use of Dopicar with dopamine-depleting agents (e.g., tetrabenazine) or other drugs known to deplete monoamine stores is not recommended.
• Concomitant therapy with selegiline and carbidopa-levodopa may be associated with severe orthostatic hypotension not attributable to carbidopa-levodopa alone (see section 4.3 ‘Contraindications’)
• Since levodopa competes with certain amino acids, the absorption of Dopicar may be impaired in some patients on a high protein diet.
• The effect of simultaneous administration of antacids with Dopicar on the bioavailability of levodopa has not been studied.
• Dopicar may be given to patients with Parkinson’s disease and syndrome who are taking vitamin preparations that contain pyridoxine hydrochloride (Vitamin B6).