MAO INHIBITORS ARE CONTRAINDICATED FOR USE WITH SYNDOPA. THESE INHIBITORS MUST BE DISCONTINUED AT LEAST TWO WEEKS PRIOR TO INITIATING THERAPY WITH SYNDOPA. HYPERTENSIVE CRISES WITH FURAZOLIDONE OR MAOIS. EFFECTS ENHANCED BY THE PERIPHERAL DOPA DECARBOXYLASE INHIBITORS, AMANTADINE, ANTICHOLINERGICS, AMPHETAMINE. ENHANCES HYPOTENSIVE EFFECTS OF ETHANIDINE, BRETYLIUM, GUANETHIDINE. PHENOTHIAZINES, HALOPERIDOL, RESERPINE, DIAZEPAM, OXAZEPAM, PYRIDOXINE,CHLORDIAZEPOXIDE, PHENOBARBITONE REDUCES EFFECTS OF LEVODOPA. ANTIMUSCARINIC ANTIPARKINSONIAN DRUGS MAY ENHANCE THE THERAPEUTIC EFFECTS OF LEVODOPA BUT BY DELAYING GASTRIC EMPTYING THEY MAY REDUCE ITS ABSORPTION. CONCURRENT USE WITH BACLOFEN; HALLUCINATION, CONFUSION, HEADACHE, AND NAUSEA AND VOMITING MAY OCCUR. ANTACID ENHANCE THE ABSORPTION OF LEVODOPA. ADRENALINE OR ISOPRENALINE MAY ENHANCE THE CARDIAC SIDE-EFFECTS OF LEVODOPA. POSTURAL HYPOTENSION HAS OCCURRED WHEN SYNDOPA IS ADDED TO THE TREATMENT OF A PATIENT RECEIVING ANTIHYPERTENSIVE DRUGS. THERE HAVE BEEN RARE REPORTS OF ADVERSE REACTIONS, INCLUDING HYPERTENSION AND DYSKINESIA, RESULTING FROM THE CONCOMITANT USE OF TRICYCLIC ANTIDEPRESSANTS. PHENOTHIAZINES, BUTYROPHENONES, RISPERIDONE) AND ISONIAZID MAY REDUCE THE THERAPEUTIC EFFECTS OF LEVODOPA. IN ADDITION, THE BENEFICIAL EFFECTS OF LEVODOPA IN PARKINSON' DISEASE HAVE BEEN REPORTED TO BE REVERSED BY PHENYTOIN AND PAPAVERINE. IRON SALTS MAY REDUCE THE BIOAVAILABILITY OF LEVODOPA AND CARBIDOPA. THE CLINICAL RELEVANCE IS UNCLEAR. ALTHOUGH METOCLOPRAMIDE MAY INCREASE THE BIOAVAILABILITY OF LEVODOPA BY INCREASING GASTRIC EMPTYING, METOCLOPRAMIDE MAY ALSO ADVERSELY AFFECT DISEASE CONTROL BY ITS DOPAMINE RECEPTOR ANTAGONISTIC PROPERTIES