Drug General Information (ID: DDI50N9DS7)
Drug Name			Levodopa		Drug Info		Fosphenytoin		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Dopaminergic Antiparkinsonism Agents				Anticonvulsants
Structure

Mechanism of Levodopa-Fosphenytoin Interaction (Severity Level: Moderate)
Attenuated pharmacological effects (Unspecific) Click to Show/Hide Mechanism Graph
Drug Name		Levodopa				Fosphenytoin
Mechanism		Levodopa				Decrease the therapeutic effects of 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  Levodopa when combined with Fosphenytoin

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