Details of Drug Interaction | MecDDI

Drug General Information (ID: DDIE8W6JZ9)
Drug Name			Guanabenz		Drug Info		Levodopa		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Sympatholytics				Dopaminergic Antiparkinsonism Agents
Structure

Mechanism of Guanabenz-Levodopa Interaction (Severity Level: Moderate)
Additive hypotensive effects Click to Show/Hide Mechanism Graph

Drug Name		Guanabenz				Levodopa
Mechanism 1		Antihypertensive agent Alpha-2 adrenergic receptor Agonist				Antihypertensive agent
Key Mechanism Factor 1
		Factor Name		Adrenergic receptor alpha-2				Structure Sequence
		Protein Family		G-protein coupled receptor 1 family
		Protein Function		Alpha-2 adrenergic receptors mediate the catecholamine-induced inhibition of adenylate cyclase through the action of G proteins. The rank order of potency for agonists of this receptor is oxymetazoline > clonidine > epinephrine > norepinephrine > phenylephrine > dopamine > p-synephrine > p-tyramine > serotonin = p-octopamine. For antagonists, the rank order is yohimbine > phentolamine = mianserine > chlorpromazine = spiperone = prazosin > propanolol > alprenolol = pindolol. Click to Show/Hide
Mechanism Description		Additive hypotensive effects by the combination of Guanabenz and Levodopa
Mechanism 2		Antihypertensive agent Alpha-2 adrenergic receptor Agonist				Hypotensive effects
Key Mechanism Factor 2
		Factor Name		Adrenergic receptor alpha-2				Structure Sequence
		Protein Family		G-protein coupled receptor 1 family
		Protein Function		Alpha-2 adrenergic receptors mediate the catecholamine-induced inhibition of adenylate cyclase through the action of G proteins. The rank order of potency for agonists of this receptor is oxymetazoline > clonidine > epinephrine > norepinephrine > phenylephrine > dopamine > p-synephrine > p-tyramine > serotonin = p-octopamine. For antagonists, the rank order is yohimbine > phentolamine = mianserine > chlorpromazine = spiperone = prazosin > propanolol > alprenolol = pindolol. Click to Show/Hide
Mechanism Description		Additive hypotensive effects by the combination of Guanabenz and Levodopa

Recommended Action
Management		Hemodynamic responses should be monitored during coadministration, especially during the first few weeks of therapy. Dose adjustments of the antihypertensive agent may be required. Patients should be advised to notify their physician if they experience dizziness or syncope.

References
1	Bailey DG, Dresser GK "Natural products and adverse drug interactions." Can Med Assoc J 170 (2004): 1531-2. [PMID: 15136542]
2	Ho PC, Ghose K, Saville D, Wanwimolruk S "Effect of grapefruit juice on pharmacokinetics and pharmacodynamics of verapamil enantiomers in healthy volunteers." Eur J Clin Pharmacol 56 (2000): 693-8. [PMID: 11214778]
3	Product Information. Stalevo 150 (carbidopa/entacapone/levodopa). Novartis Pharmaceuticals, East Hanover, NJ.