Details of Drug Interaction | MecDDI

Drug General Information (ID: DDIN3RWBFP)
Drug Name			Tizanidine		Drug Info		Indapamide		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Analgesics				Antihypertensive Agents
Structure

Mechanism of Tizanidine-Indapamide Interaction (Severity Level: Major)
Additive hypotensive effects Click to Show/Hide Mechanism Graph

Drug Name		Tizanidine				Indapamide
Mechanism		Hypotensive effects Alpha-2 adrenergic receptor Agonist				Hypotensive effects Voltage-gated potassium channel Blocker
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
Key Mechanism Factor 2
		Factor Name		Voltage-gated potassium channel Kv7.1				× Structure Sequence MAAASSPPRAERKRWGWGRLPGARRGSAGLAKKCPFSLELAEGGPAGGALYAPIAPGAPGPAPPASPAAPAAPPVASDLGPRPPVSLDPRVSIYSTRRPVLARTHVQGRVYNFLERPTGWKCFVYHFAVFLIVLVCLIFSVLSTIEQYAALATGTLFWMEIVLVVFFGTEYVVRLWSAGCRSKYVGLWGRLRFARKPISIIDLIVVVASMVVLCVGSKGQVFATSAIRGIRFLQILRMLHVDRQGGTWRLLGSVVFIHRQELITTLYIGFLGLIFSSYFVYLAEKDAVNESGRVEFGSYADALWWGVVTVTTIGYGDKVPQTWVGKTIASCFSVFAISFFALPAGILGSGFALKVQQKQRQKHFNRQIPAAASLIQTAWRCYAAENPDSSTWKIYIRKAPRSHTLLSPSPKPKKSVVVKKKKFKLDKDNGVTPGEKMLTVPHITCDPPEERRLDHFSVDGYDSSVRKSPTLLEVSMPHFMRTNSFAEDLDLEGETLLTPITHISQLREHHRATIKVIRRMQYFVAKKKFQQARKPYDVRDVIEQYSQGHLNLMVRIKELQRRLDQSIGKPSLFISVSEKSKDRGSNTIGARLNRVEDKVTQLDQRLALITDMLHQLLSLHGGSTPGSGGPPREGGAHITQPCGSGGSVDPELFLPSNTLPTYEQLTVPRRGPDEGS
		Gene Name		KCNQ1
		Uniprot ID		KCNQ1_HUMAN
		KEGG Pathway		hsa:3784
		Protein Family		Potassium channel family
		Protein Function		Potassium channel that plays an important role in a number of tissues, including heart, inner ear, stomach and colon (PubMed:10646604, PubMed:25441029). Associates with KCNE beta subunits that modulates current kinetics (PubMed:9312006, PubMed:9108097, PubMed:8900283, PubMed:10646604, PubMed:11101505, PubMed:19687231). Induces a voltage-dependent current by rapidly activating and slowly deactivating potassium-selective outward current (PubMed:9312006, PubMed:9108097, PubMed:8900283, PubMed:10646604, PubMed:11101505, PubMed:25441029). Promotes also a delayed voltage activated potassium current showing outward rectification characteristic (By similarity). During beta-adrenergic receptor stimulation participates in cardiac repolarization by associating with KCNE1 to form the I(Ks) cardiac potassium current that increases the amplitude and slows down the activation kinetics of outward potassium current I(Ks) (By similarity) (PubMed:9312006, PubMed:9108097, PubMed:8900283, PubMed:10646604, PubMed:11101505). Muscarinic agonist oxotremorine-M strongly suppresses KCNQ1/KCNE1 current (PubMed:10713961). When associated with KCNE3, forms the potassium channel that is important for cyclic AMP-stimulated intestinal secretion of chloride ions (PubMed:10646604). This interaction with KCNE3 is reduced by 17beta-estradiol, resulting in the reduction of currents (By similarity). During conditions of increased substrate load, maintains the driving force for proximal tubular and intestinal sodium ions absorption, gastric acid secretion, and cAMP-induced jejunal chloride ions secretion (By similarity). Allows the provision of potassium ions to the luminal membrane of the secretory canaliculus in the resting state as well as during stimulated acid secretion (By similarity). When associated with KCNE2, forms a heterooligomer complex leading to currents with an apparently instantaneous activation, a rapid deactivation process and a linear current-voltage relationship and decreases the amplitude of the outward current (PubMed:11101505). When associated with KCNE4, inhibits voltage-gated potassium channel activity (PubMed:19687231). When associated with KCNE5, this complex only conducts current upon strong and continued depolarization (PubMed:12324418). Also forms a heterotetramer with KCNQ5; has a voltage-gated potassium channel activity (PubMed:24855057). Binds with phosphatidylinositol 4,5-bisphosphate (PubMed:25037568). Click to Show/Hide
Mechanism Description		Additive hypotensive effects by the combination of Tizanidine and Indapamide

Recommended Action
Management		A lower initial dosage and cautious dosage titration should be considered when tizanidine is initiated in patients receiving hypotensive medications. Although single doses of less than 8 mg of tizanidine have not been shown effective for spasticity in controlled clinical studies, it may be prudent to initiate treatment with 4 mg doses and gradually increase in 2 to 4 mg increments until optimum effect is achieved. The dose can be repeated at 6 to 8 hour intervals as needed, up to a maximum of three doses in 24 hours and a total daily dosage of 36 mg. However, experience with single doses exceeding 8 mg and daily doses exceeding 24 mg is limited. Close monitoring for development of hypotension is recommended.

References
1	Product Information. Zanaflex (tizanidine). Acorda Therapeutics, Hawthorne, NY.