Drug General Information (ID: DDIGCZOUA4)
Drug Name			Phenytoin		Drug Info		Levodopa		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Anticonvulsants				Dopaminergic Antiparkinsonism Agents
Structure

Mechanism of Phenytoin-Levodopa Interaction (Severity Level: Moderate)
Attenuated pharmacological effects (Unspecific) Click to Show/Hide Mechanism Graph
Drug Name		Phenytoin				Levodopa
Mechanism		Decrease the therapeutic effects of levodopa				Levodopa
Key Mechanism Factor 1
		Factor Name		Pharmacodynamics
		Factor Description		Reduced pharmacological effects leading to insufficient efficacy and/or treatment failure.
Mechanism Description		Attenuated pharmacological effects of  Phenytoin when combined with Levodopa

Recommended Action
Management		If phenytoin and levodopa must be used together, close observation for evidence of altered levodopa effects is recommended. Patients should be advised to notify their physician if they experience a worsening of their parkinsonian symptoms. Levodopa dosage increases or alternatives to phenytoin may be required if evidence of an interaction is observed.

References
1	Cerner Multum, Inc. "Australian Product Information.".
2	Ozuna J, Friel P "Effect of enteral tube feeding on serum phenytoin levels." J Neurosurg Nurs 16 (1984): 289-91
3	Mendez JS, Cotzias GC, Mena I, Papavasiliou PS "Diphenylhydantoin. Blocking of levodopa effects." Arch Neurol 32 (1975): 44-6