Details of Drug Interaction | MecDDI

Drug General Information (ID: DDI8B73J2W)
Drug Name			Loxapine		Drug Info		Indapamide		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antipsychotic Agents				Antihypertensive Agents
Structure

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

Drug Name		Loxapine				Indapamide
Mechanism		Hypotensive effects Alpha-1 adrenergic receptor Antagonist				Hypotensive effects Voltage-gated potassium channel Blocker
Key Mechanism Factor 1
		Factor Name		Adrenergic receptor alpha-1				Structure Sequence
		Protein Family		G-protein coupled receptor 1 family
		Protein Function		This alpha-adrenergic receptor mediates its action by association with G proteins that activate a phosphatidylinositol-calcium second messenger system. Its effect is mediated by G(q) and G(11) proteins. Nuclear ADRA1A-ADRA1B heterooligomers regulate phenylephrine(PE)-stimulated ERK signaling in cardiac myocytes. 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 Loxapine and Indapamide

Recommended Action
Management		Close clinical monitoring for development of hypotension is recommended if phenothiazines or neuroleptic agents are used in patients receiving antihypertensive medications or vasodilators. A lower starting dosage and slower titration of the phenothiazine or neuroleptic may be appropriate, especially in the elderly. Patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia. Patients should also avoid driving or operating hazardous machinery.

References
1	Aronowitz JS, Chakos MH, Safferman AZ, Lieberman JA "Syncope associated with the combination of clozapine and enalapril." J Clin Psychopharmacol 14 (1994): 429-30. [PMID: 7884028]
2	Fruncillo R, Gibbons W, Vlasses P, Ferguson R "Severe hypotension associated with concurrent clonidine and antipsychotic medication." Am J Psychiatry 142 (1985): 274. [PMID: 2857531]
3	Markowitz JS, Wells BG, Carson WH "Interactions between antipsychotic and antihypertensive drugs." Ann Pharmacother 29 (1995): 603-9. [PMID: 7663034]
4	Product Information. Abilify (aripiprazole). Bristol-Myers Squibb, Princeton, NJ.
5	Product Information. Clozaril (clozapine). Novartis Pharmaceuticals, East Hanover, NJ.
6	Product Information. Geodon (ziprasidone). Pfizer US Pharmaceuticals, New York, NY.
7	Product Information. Rexulti (brexpiprazole). Otsuka American Pharmaceuticals Inc, Rockville, MD.
8	Product Information. Risperdal (risperidone). Janssen Pharmaceutica, Titusville, NJ.
9	Product Information. Seroquel (quetiapine). Zeneca Pharmaceuticals, Wilmington, DE.
10	Product Information. Zyprexa (olanzapine). Lilly, Eli and Company, Indianapolis, IN.
11	White WB "Hypotension with postural syncope secondary to the combination of chlorpromazine and captopril." Arch Intern Med 146 (1986): 1833-4. [PMID: 3530167]