Table 1.

Overview of possible therapeutic approaches to combat various causes of peripheral levodopa resistance.

	Causes of peripheral levodopa resistance
	Bacterial TDC production	Peripheral AADC induction	SIBO-related malabsorption of drugs
Oral dopamine agonist	+	+
Parenteral dopaminergic therapy	+	+ (except levodopa-containing preparations)	+
Antibiotic therapy	+		+

TDC tyrosine decarboxylase, AADC aromatic L-amino acid decarboxylase, SIBO small-intestinal bacterial overgrowth.