Summary: An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.

Top Publications

  1. Schiffer R, Pope L. Review of pseudobulbar affect including a novel and potential therapy. J Neuropsychiatry Clin Neurosci. 2005;17:447-54 pubmed
    ..that treatment with a fixed combination of dextromethorphan and the cytochrome P450 2D6 enzyme inhibitor, quinidine, can improve PBA...
  2. Stokoe K, Balasubramaniam R, Goddard C, Colledge W, Grace A, Huang C. Effects of flecainide and quinidine on arrhythmogenic properties of Scn5a+/- murine hearts modelling the Brugada syndrome. J Physiol. 2007;581:255-75 pubmed
    ..genetically modified (Scn5a+/-) 'loss-of-function' murine hearts in the presence and absence of flecainide and quinidine, and the extent to which Scn5a+/- hearts model the human BrS...
  3. Shen Q, Li W, Lin Y, Katsumi H, Okada N, Sakane T, et al. Modulating effect of polyethylene glycol on the intestinal transport and absorption of prednisolone, methylprednisolone and quinidine in rats by in-vitro and in-situ absorption studies. J Pharm Pharmacol. 2008;60:1633-41 pubmed publisher
    ..of polyethylene glycol 20000 (PEG 20000) on the intestinal absorption of prednisolone, methylprednisolone and quinidine, three P-glycoprotein (P-gp) substrates, across the isolated rat intestinal membranes were examined by an in-..
  4. Huston M, Levinson M. Are one or two dangerous? Quinine and quinidine exposure in toddlers. J Emerg Med. 2006;31:395-401 pubmed
    Quinine and quinidine have been cited as drugs that may cause significant morbidity and mortality in toddlers who ingest one or two pills. The use of both of these drugs has declined in the United States since the 1980s...
  5. Martin C, Zhang Y, Grace A, Huang C. In vivo studies of Scn5a+/- mice modeling Brugada syndrome demonstrate both conduction and repolarization abnormalities. J Electrocardiol. 2010;43:433-9 pubmed publisher
    ..and Scn5a+/- mice, before and after administration of the known pro- and antiarrhythmic agents flecainide and quinidine. The ECG intervals were measured and their dispersions calculated...
  6. Yang H, Lopina S. Stealth dendrimers for antiarrhythmic quinidine delivery. J Mater Sci Mater Med. 2007;18:2061-5 pubmed
    ..In this study, synthetic methods were explored to deliver antiarrhythmic quinidine by stealth dendrimers. In particular, quinidine was covalently attached to anionic G2.5 and cationic G3...
  7. Brooks B, Thisted R, Appel S, Bradley W, Olney R, Berg J, et al. Treatment of pseudobulbar affect in ALS with dextromethorphan/quinidine: a randomized trial. Neurology. 2004;63:1364-70 pubmed
    ..Patients with ALS commonly exhibit pseudobulbar affect...
  8. Watanabe H, Chinushi M, Washizuka T, Sugiura H, Hirono T, Komura S, et al. Variable electrocardiographic effects of short-term quinidine sulfate administration in Brugada syndrome. Pacing Clin Electrophysiol. 2005;28:372-7 pubmed
    b>Quinidine, a class I antiarrhythmic agent with blocking property of transient outward current, is a possible candidate for the suppression of ventricular fibrillation in patients with Brugada syndrome; although there is a concern that ..
  9. Jain R, Majumdar S, Nashed Y, Pal D, Mitra A. Circumventing P-glycoprotein-mediated cellular efflux of quinidine by prodrug derivatization. Mol Pharm. 2004;1:290-9 pubmed
    The objective of this study is to investigate whether transporter-targeted prodrug derivatization of quinidine, a model P-glycoprotein (P-gp) substrate, can circumvent P-gp-mediated efflux...

More Information


  1. Varma M, Panchagnula R. pH-dependent functional activity of P-glycoprotein in limiting intestinal absorption of protic drugs: kinetic analysis of quinidine efflux in situ. J Pharm Sci. 2005;94:2632-43 pubmed
    ..partition coefficient, artificial membrane permeability and in situ rat intestinal permeability of quinidine were determined in the physiological pH range of gastrointestinal tract...
  2. Wolpert C, Schimpf R, Giustetto C, Antzelevitch C, Cordeiro J, Dumaine R, et al. Further insights into the effect of quinidine in short QT syndrome caused by a mutation in HERG. J Cardiovasc Electrophysiol. 2005;16:54-8 pubmed
    The principal aim of this study was to assess the efficacy of quinidine in suppressing IKr in vitro and in modulating the rate dependence of the QT interval in the "SQT1" form of the short QT syndrome...
  3. Tenreiro S, Vargas R, Teixeira M, Magnani C, Sá Correia I. The yeast multidrug transporter Qdr3 (Ybr043c): localization and role as a determinant of resistance to quinidine, barban, cisplatin, and bleomycin. Biochem Biophys Res Commun. 2005;327:952-9 pubmed
    ..superfamily required for multiple drug resistance, encodes a plasma membrane protein that confers resistance to quinidine and barban, as observed before for its close homologues QDR1 and QDR2. This ORF was, thus, named the QDR3 gene...
  4. Ashino S, Watanabe I, Kofune M, Nagashima K, Ohkubo K, Okumura Y, et al. Effects of quinidine on the action potential duration restitution property in the right ventricular outflow tract in patients with brugada syndrome. Circ J. 2011;75:2080-6 pubmed
    ..The effects of quinidine gluconate, a potent inhibitor of I(to), on RVOT action potential duration (APD) restitution kinetics in patients ..
  5. Margineanu D, Klitgaard H. The connexin 36 blockers quinine, quinidine and mefloquine inhibit cortical spreading depression in a rat neocortical slice model in vitro. Brain Res Bull. 2006;71:23-8 pubmed
    ..Quinine, its stereoisomer quinidine, and mefloquine consistently inhibited the SD episodes...
  6. Pioro E, Brooks B, Cummings J, Schiffer R, Thisted R, Wynn D, et al. Dextromethorphan plus ultra low-dose quinidine reduces pseudobulbar affect. Ann Neurol. 2010;68:693-702 pubmed publisher
    To evaluate dextromethorphan combined with ultra low-dose quinidine (DMq) for treating pseudobulbar affect (PBA) in patients with amyotrophic lateral sclerosis (ALS) or multiple sclerosis (MS)...
  7. McLaughlin L, Paine M, Kemp C, Marechal J, Flanagan J, Ward C, et al. Why is quinidine an inhibitor of cytochrome P450 2D6? The role of key active-site residues in quinidine binding. J Biol Chem. 2005;280:38617-24 pubmed
    ..the effect of mutations of these residues on interactions of the enzyme with the prototypical CYP2D6 inhibitor, quinidine. Abolition of the negative charge at either or both residues 216 and 301 decreased quinidine inhibition of ..
  8. Rosen H. Dextromethorphan/quinidine sulfate for pseudobulbar affect. Drugs Today (Barc). 2008;44:661-8 pubmed publisher
    A new agent containing a combination of dextromethorphan (DM) and quinidine (Q) is currently under development for the treatment of pseudobulbar affect (PBA)...
  9. Tsai P, Tsai T. Pharmacokinetics of baicalin in rats and its interactions with cyclosporin A, quinidine and SKF-525A: a microdialysis study. Planta Med. 2004;70:1069-74 pubmed
    ..Coadministration of cyclosporin A (CsA) or quinidine (both are P-gp inhibitors) was used to delineate the role of P-gp on baicalin disposition, while SKF-525A (a ..
  10. Marquez M, Bonny A, Hernández Castillo E, De Sisti A, Gómez Flores J, Nava S, et al. Long-term efficacy of low doses of quinidine on malignant arrhythmias in Brugada syndrome with an implantable cardioverter-defibrillator: a case series and literature review. Heart Rhythm. 2012;9:1995-2000 pubmed publisher
    To prevent the recurrence of ventricular arrhythmias (VA) in Brugada syndrome (BrS), only quinidine has been consistently reported to have a beneficial effect. Recommended doses are ? 1 g/d...
  11. Yang F, Hanon S, Lam P, Schweitzer P. Quinidine revisited. Am J Med. 2009;122:317-21 pubmed publisher
    One of the earliest antiarrhythmic drugs developed, quinidine had a significant role in the treatment of many arrhythmias...
  12. Acharya P, O Connor M, Polli J, Ayrton A, Ellens H, Bentz J. Kinetic identification of membrane transporters that assist P-glycoprotein-mediated transport of digoxin and loperamide through a confluent monolayer of MDCKII-hMDR1 cells. Drug Metab Dispos. 2008;36:452-60 pubmed
    ..we have determined the elementary rate constants for the P-gp efflux of amprenavir, digoxin, loperamide, and quinidine. For amprenavir and quinidine, transport was fitted with just P-gp and passive permeability...
  13. Milberg P, Tegelkamp R, Osada N, Schimpf R, Wolpert C, Breithardt G, et al. Reduction of dispersion of repolarization and prolongation of postrepolarization refractoriness explain the antiarrhythmic effects of quinidine in a model of short QT syndrome. J Cardiovasc Electrophysiol. 2007;18:658-64 pubmed
    ..with the I(Kr) blocker sotalol (100 microM) and the class I antiarrhythmic drugs flecainide (2 microM) and quinidine (0...
  14. Grube S, Langguth P, Junginger H, Kopp S, Midha K, Shah V, et al. Biowaiver monographs for immediate release solid oral dosage forms: quinidine sulfate. J Pharm Sci. 2009;98:2238-51 pubmed publisher
    ..for the approval of new multisource and reformulated immediate release (IR) solid oral dosage forms containing quinidine sulfate...
  15. Berka K, Anzenbacherova E, Hendrychová T, Lange R, Masek V, Anzenbacher P, et al. Binding of quinidine radically increases the stability and decreases the flexibility of the cytochrome P450 2D6 active site. J Inorg Biochem. 2012;110:46-50 pubmed publisher
    ..present a combined experimental and computational study on the compressibility and flexibility of unliganded and quinidine-bound CYP2D6...
  16. Vargas R, García Salcedo R, Tenreiro S, Teixeira M, Fernandes A, Ramos J, et al. Saccharomyces cerevisiae multidrug resistance transporter Qdr2 is implicated in potassium uptake, providing a physiological advantage to quinidine-stressed cells. Eukaryot Cell. 2007;6:134-42 pubmed
    ..Saccharomyces cerevisiae encodes a putative plasma membrane drug:H(+) antiporter that confers resistance against quinidine, barban, bleomycin, and cisplatin...
  17. Barrows B, Cheung K, Bialobrzeski T, Foster J, Schulze J, Miller A. Extracellular potassium dependency of block of HERG by quinidine and cisapride is primarily determined by the permeant ion and not by inactivation. Channels (Austin). 2009;3:239-48 pubmed
    ..In this study, HERG block by quinidine and cisapride was assessed in extracellular solutions of calcium, potassium, rubidium, cesium and ..
  18. Mizusawa Y, Sakurada H, Nishizaki M, Hiraoka M. Effects of low-dose quinidine on ventricular tachyarrhythmias in patients with Brugada syndrome: low-dose quinidine therapy as an adjunctive treatment. J Cardiovasc Pharmacol. 2006;47:359-64 pubmed
    b>Quinidine is suggested as an effective agent to suppress ventricular fibrillation (VF) in the Brugada syndrome by inhibiting transient outward K(+) current (Ito) leading to the reduction and abbreviation of the disparity of ..
  19. Kuroha M, Shirai Y, Shimoda M. Multiple oral dosing of ketoconazole influences pharmacokinetics of quinidine after intravenous and oral administration in beagle dogs. J Vet Pharmacol Ther. 2004;27:355-9 pubmed
    In this study, we investigated the effect of multiple oral dosing of ketoconazole (KTZ) on pharmacokinetics of quinidine (QN), a CYP3A substrate with low hepatic clearance, after i.v. and oral administration in beagle dogs...
  20. Cooper R, Lane K, Deng B, Mu J, Patel J, Wellems T, et al. Mutations in transmembrane domains 1, 4 and 9 of the Plasmodium falciparum chloroquine resistance transporter alter susceptibility to chloroquine, quinine and quinidine. Mol Microbiol. 2007;63:270-82 pubmed
    ..affected quantitative CQ susceptibility and accumulation as well as the stereospecific responses to quinine and quinidine. These results, together with a previously described S163R mutation in transmembrane domain 4, indicate that ..
  21. Ai C, Li Y, Wang Y, Chen Y, Yang L. Insight into the effects of chiral isomers quinidine and quinine on CYP2D6 inhibition. Bioorg Med Chem Lett. 2009;19:803-6 pubmed publisher
    The distinct inhibitory effects against CYP2D6 enzyme of the stereoisomers quinidine and quinine were investigated in this work by employing various methods, including the comparative molecular field analysis (CoMFA), the comparative ..
  22. Belhassen B, Glick A, Viskin S. Excellent long-term reproducibility of the electrophysiologic efficacy of quinidine in patients with idiopathic ventricular fibrillation and Brugada syndrome. Pacing Clin Electrophysiol. 2009;32:294-301 pubmed publisher
    b>Quinidine is very effective in preventing the reinduction of sustained ventricular fibrillation (VF) during electrophysiologic study (EPS) in patients with idiopathic VF and Brugada syndrome...
  23. Inama G, Durin O, Pedrinazzi C, Berisso M, Furlanello F. 'Orphan drugs' in cardiology: nadolol and quinidine. J Cardiovasc Med (Hagerstown). 2010;11:143-4 pubmed publisher
    The recent withdrawal from the market of nadolol (Corgard; Bristol-Myers Squibb, Sermoneta, Italy) and quinidine polygalacturonate (Ritmocor; Malesci, Bagno A Ripoli, Italy) has been causing clinical problems to many cardiologists and ..
  24. Izuwa Y, Kusaba J, Horiuchi M, Aiba T, Kawasaki H, Kurosaki Y. Comparative study of increased plasma quinidine concentration in rats with glycerol- and cisplatin-induced acute renal failure. Drug Metab Pharmacokinet. 2009;24:451-7 pubmed
    A comparative study of altered plasma concentration of quinidine in rats with glycerol- and cisplatin-induced acute renal failure (ARF) was conducted with quinidine used as a positively charged and liver-metabolized therapeutic compound...
  25. Kosior D, Kochanowski J, Scisło P, Piatkowski R, Postuła M, Rabczenko D, et al. Efficacy and tolerability of oral propafenone versus quinidine in the treatment of recent onset atrial fibrillation: A randomized, prospective study. Cardiol J. 2009;16:521-7 pubmed
    A prospective, randomized study was conducted to evaluate the efficacy and tolerability of oral propafenone and quinidine for the conversion of paroxysmal atrial fibrillation (AF)...
  26. Smith R. Dextromethorphan/quinidine: a novel dextromethorphan product for the treatment of emotional lability. Expert Opin Pharmacother. 2006;7:2581-98 pubmed
    ..DM is currently being reintroduced as the active ingredient in a novel combination product in which low-dose quinidine is added to inhibit its breakdown, elevating blood levels of DM and increasing its likelihood of reaching ..
  27. Giustetto C, Schimpf R, Mazzanti A, Scrocco C, Maury P, Anttonen O, et al. Long-term follow-up of patients with short QT syndrome. J Am Coll Cardiol. 2011;58:587-95 pubmed publisher
    ..Symptomatic patients have a high risk of recurrent arrhythmic events. HQ is effective in preventing ventricular tachyarrhythmia induction and arrhythmic events during long-term follow-up. ..
  28. Illa O, Arshad M, Ros A, McGarrigle E, Aggarwal V. Practical and highly selective sulfur ylide mediated asymmetric epoxidations and aziridinations using an inexpensive, readily available chiral sulfide. Applications to the synthesis of quinine and quinidine. J Am Chem Soc. 2010;132:1828-30 pubmed publisher
    ..The epoxidation has been used as the key step in a convergent and stereoselective synthesis of each of the diastereoisomers of the cinchona alkaloids, quinine and quinidine.
  29. Tran T, Mittal A, Aldinger T, Polli J, Ayrton A, Ellens H, et al. The elementary mass action rate constants of P-gp transport for a confluent monolayer of MDCKII-hMDR1 cells. Biophys J. 2005;88:715-38 pubmed
    ..For three P-gp substrates (amprenavir, loperamide, and quinidine), we have successfully fitted the elementary rate constants, i.e...
  30. Lee S, Rhee Y, Jeong S, Lee H, Lee H, Jung M, et al. Hydrocinchonine, cinchonine, and quinidine potentiate paclitaxel-induced cytotoxicity and apoptosis via multidrug resistance reversal in MES-SA/DX5 uterine sarcoma cells. Environ Toxicol. 2011;26:424-31 pubmed publisher
    ..Despite some MDR reversal evidences of natural compounds including quinidine and cinchonine, there are no reports on MDR reversal activity of hydrocinchonine with its analogues quinidine ..
  31. Martin C, Grace A, Huang C. Spatial and temporal heterogeneities are localized to the right ventricular outflow tract in a heterozygotic Scn5a mouse model. Am J Physiol Heart Circ Physiol. 2011;300:H605-16 pubmed publisher
    ..This was accentuated by flecainide, but reduced by quinidine, in parallel with their respective pro- and anti-arrhythmic effects...
  32. Gorka A, Sherlach K, De Dios A, Roepe P. Relative to quinine and quinidine, their 9-epimers exhibit decreased cytostatic activity and altered heme binding but similar cytocidal activity versus Plasmodium falciparum. Antimicrob Agents Chemother. 2013;57:365-74 pubmed publisher
    The 9-epimers of quinine (QN) and quinidine (QD) are known to exhibit poor cytostatic potency against P. falciparum (Karle JM, Karle IL, Gerena L, Milhous WK, Antimicrob. Agents Chemother. 36:1538-1544, 1992)...
  33. Panitch H, Thisted R, Smith R, Wynn D, Wymer J, Achiron A, et al. Randomized, controlled trial of dextromethorphan/quinidine for pseudobulbar affect in multiple sclerosis. Ann Neurol. 2006;59:780-7 pubmed
    To evaluate the efficacy and safety of DM/Q (capsules containing dextromethorphan [DM] and quinidine [Q]) compared with placebo, taken twice daily, for the treatment of pseudobulbar affect over a 12-week period in multiple sclerosis ..
  34. Ablin J, Verbovetski I, Trahtemberg U, Metzger S, Mevorach D. Quinidine and procainamide inhibit murine macrophage uptake of apoptotic and necrotic cells: a novel contributing mechanism of drug-induced-lupus. Apoptosis. 2005;10:1009-18 pubmed
    ..A number of mechanisms have been proposed to explain the etiology of drug-induced lupus (DIL) but the effect of apoptotic and necrotic cell handling has not been previously examined...
  35. Sziráki I, Erdo F, Beéry E, Molnár P, Fazakas C, Wilhelm I, et al. Quinidine as an ABCB1 probe for testing drug interactions at the blood-brain barrier: an in vitro in vivo correlation study. J Biomol Screen. 2011;16:886-94 pubmed publisher
    This study provides evidence that quinidine can be used as a probe substrate for ABCB1 in multiple experimental systems both in vitro and in vivo relevant to the blood-brain barrier (BBB)...
  36. Kodaira H, Kusuhara H, Fujita T, Ushiki J, Fuse E, Sugiyama Y. Quantitative evaluation of the impact of active efflux by p-glycoprotein and breast cancer resistance protein at the blood-brain barrier on the predictability of the unbound concentrations of drugs in the brain using cerebrospinal fluid concentration. J Pharmacol Exp Ther. 2011;339:935-44 pubmed publisher
    ..P-gp and/or Bcrp substrates, such as verapamil, loperamide, flavopiridol, genistein, quinidine, dantrolene, daidzein, cimetidine, and pefloxacin, showed a higher CSF-to-brain unbound concentration ratio (K(p,..
  37. Syvänen S, Schenke M, van den Berg D, Voskuyl R, de Lange E. Alteration in P-glycoprotein functionality affects intrabrain distribution of quinidine more than brain entry-a study in rats subjected to status epilepticus by kainate. AAPS J. 2012;14:87-96 pubmed publisher
    This study aimed to investigate the use of quinidine microdialysis to study potential changes in brain P-glycoprotein functionality after induction of status epilepticus (SE) by kainate...
  38. Pandey S, Dwivedi H, Singh S, Siddiqui W, Tripathi R. Antimalarial interaction of quinine and quinidine with clarithromycin. Parasitology. 2013;140:406-13 pubmed publisher
    Quinine (QN) and quinidine (QND) have been commonly used as effective and affordable antimalarials for over many years. Quinine primarily is used for severe malaria treatment...
  39. Viskin S, Wilde A, Guevara Valdivia M, Daoulah A, Krahn A, Zipes D, et al. Quinidine, a life-saving medication for Brugada syndrome, is inaccessible in many countries. J Am Coll Cardiol. 2013;61:2383-7 pubmed publisher
    The aim of this study was to determine the availability of quinidine throughout the world...
  40. Polak S. In vitro to human in vivo translation - pharmacokinetics and pharmacodynamics of quinidine. ALTEX. 2013;30:309-18 pubmed publisher
    ..Here, quinidine was chosen as an example of a drug with cardiac effects and results of nine published clinical studies ..
  41. Pioro E. Current concepts in the pharmacotherapy of pseudobulbar affect. Drugs. 2011;71:1193-207 pubmed publisher
    ..The three randomized, double-blind studies of dextromethorphan plus quinidine assessed 129, 150 and 326 subjects...
  42. Hakim P, Thresher R, Grace A, Huang C. Effects of flecainide and quinidine on action potential and ventricular arrhythmogenic properties in Scn3b knockout mice. Clin Exp Pharmacol Physiol. 2010;37:782-9 pubmed publisher
    1. Flecainide and quinidine exert contrasting pro-arrhythmic and anti-arrhythmic effects in mouse hearts containing the loss-of-function, Scn5a(+/-), and the gain-of-function, Scn5a(+/DeltaKPQ), mutations in their sodium channel alpha-..
  43. Tang Q, Zhang Z, Xia X, Lingle C. Block of mouse Slo1 and Slo3 K+ channels by CTX, IbTX, TEA, 4-AP and quinidine. Channels (Austin). 2010;4:22-41 pubmed
    ..b>Quinidine was more effective in blocking Slo3 than Slo1...
  44. Lumen A, Acharya P, Polli J, Ayrton A, Ellens H, Bentz J. If the KI is defined by the free energy of binding to P-glycoprotein, which kinetic parameters define the IC50 for the Madin-Darby canine kidney II cell line overexpressing human multidrug resistance 1 confluent cell monolayer?. Drug Metab Dispos. 2010;38:260-9 pubmed publisher
  45. Wu L, Guo D, Li H, Hackett J, Yan G, Jiao Z, et al. Role of late sodium current in modulating the proarrhythmic and antiarrhythmic effects of quinidine. Heart Rhythm. 2008;5:1726-34 pubmed publisher
    b>Quinidine is used to treat atrial fibrillation and ventricular arrhythmias. However, at low concentrations, it can induce torsade de pointes (TdP)...
  46. Fenton F, Cherry E, Kornreich B. Termination of equine atrial fibrillation by quinidine: an optical mapping study. J Vet Cardiol. 2008;10:87-103 pubmed publisher
    ..of equine atrium to assess the spatiotemporal dynamics of atrial fibrillation (AF) and of its termination by quinidine. Intact, perfused atrial preparations obtained from four horses with normal cardiovascular examinations...
  47. Kaufman E. Quinidine in short QT syndrome: an old drug for a new disease. J Cardiovasc Electrophysiol. 2007;18:665-6 pubmed
  48. Acharya P, Tran T, Polli J, Ayrton A, Ellens H, Bentz J. P-Glycoprotein (P-gp) expressed in a confluent monolayer of hMDR1-MDCKII cells has more than one efflux pathway with cooperative binding sites. Biochemistry. 2006;45:15505-19 pubmed
    ..e., the inhibitor became effective. These data and their analysis show that the binding of these substrates must be cooperative, either positive or negative. ..
  49. Shin J, Kang W, Shon J, Arefayene M, Yoon Y, Kim K, et al. Possible interethnic differences in quinidine-induced QT prolongation between healthy Caucasian and Korean subjects. Br J Clin Pharmacol. 2007;63:206-15 pubmed
    The aim of this study was to evaluate the pharmacokinetics and pharmacodynamics of quinidine-induced QT prolongation in healthy Caucasian and Korean subjects to investigate interethnic differences in susceptibility to drug-induced ..
  50. Sun Y, Quan X, Fromme S, Cox R, Zhang P, Zhang L, et al. A novel mutation in the KCNH2 gene associated with short QT syndrome. J Mol Cell Cardiol. 2011;50:433-41 pubmed publisher
    ..Kinetic analysis revealed slower inactivation rates of T618I but faster rates of recovery from inactivation. Quinidine (5 ?M) and sotalol (500 ?M) had similar inhibitory effects on steady currents measured at +20 mV in WT and T618I ..
  51. Viskin S, Antzelevitch C, Marquez M, Belhassen B. Quinidine: a valuable medication joins the list of 'endangered species'. Europace. 2007;9:1105-6 pubmed
  52. Stokoe K, Thomas G, Goddard C, Colledge W, Grace A, Huang C. Effects of flecainide and quinidine on arrhythmogenic properties of Scn5a+/Delta murine hearts modelling long QT syndrome 3. J Physiol. 2007;578:69-84 pubmed
    ..Electrophysiological effects of flecainide and quinidine were compared in Langendorff-perfused wild-type (WT), and genetically modified (Scn5a+/Delta) murine hearts ..
  53. Ballestero J, Plazas P, Kracun S, Gómez Casati M, Taranda J, Rothlin C, et al. Effects of quinine, quinidine, and chloroquine on alpha9alpha10 nicotinic cholinergic receptors. Mol Pharmacol. 2005;68:822-9 pubmed
    In this study, we report the effects of the quinoline derivatives quinine, its optical isomer quinidine, and chloroquine on alpha9alpha10-containing nicotinic acetylcholine receptors (nAChRs)...