Dofetilide API   Haorui supplies Dofetilide API (Active Pharmaceutical Ingredients) to pharmaceutical industry.  Our bulk Dofetilide actives is produced by GMP facility. Welcome to contact us for product detail.   The following information is provided for general information purposes ONLY.   What is Dofetilide Dofetilide is a class III antiarrhythmic drug, which produces its antiarrhythmic actions by blocking particular potassium current in the heart.  The effect of this potassium current blockade is to make the heart less susceptible to arrhythmias. It is different from other class III antiarrhythmics in that it exhibits selective potassium channel blockade, with no effect on the conduction system. Dofetilide prolongs both atrial and ventricular repolarization, and therefore increases the refractory period within the cardiac muscle.   Other class III antiarrhythmic agents possess additional antiarrhythmic properties. Sotalol (a ß-blocker) and amiodarone decrease AV nodal conduction. For this reason, coupled with the organ toxicities of amiodarone (e.g. pulmonary fibrosis, thyroid and hepatic dysfunction), these agents are not suitable for all patients. The selective mechanism of dofetilide appears to be better than other agents in its class; however, dofetilide must still be used with caution due to its adverse effects.   How does Dofetilide work? Dofetilide regulates the flow of potassium into the heart cells.  Since the flow of this ion is crucial to the generation and transmission of electrical activity in the heart, regulation of this flow can prevent irregular heartbeats.   The history of Dofetilide  Dofetilide is the most recently approved antiarrhythmic in the United States.  Its effectiveness was shown in a number of large clinical trials, such as the EMERALD and the SAFIRE trials.  These trials showed that patients given dofetilide were more likely to convert from atrial fibrillation or flutter to normal sinus rhythm than patients given dummy pills.  Patients on dofetilide were also more likely to stay in normal rhythm after conversion to normal heart rhythm.  Dofetilide was also evaluated in two large mortality trials, known as the DIAMOND trials.  These trials evaluated patients were in the hospital with either congestive heart failure or after a recent heart attack.  The trials showed that, on balance, dofetilide did not increase mortality in either of these two patient groups, and during follow-up the patients were less likely to be in atrial fibrillation, and also less likely to be readmitted to hospital with congestive heart failure.   What is Dofetilide used for? Dofetilide is given twice a day.  It is predominantly excreted from the body by the kidneys; therefore kidney function is always measured both before initiating the drug and during follow-up of patients who are taking it.  To a small extent, dofetilide is broken down in the liver, although this mechanism of excretion is thought to be less important than excretion through the kidneys.  The doses available of dofetilide are 125, 250, and 500 mcg twice a day.   Dofetilide mode of action The impetus was the heightened awareness of the potential for drug-induced torsades de pointes (demonstrated by the removal of astemizole, terfenadine, and cisapride from the market). In order for dofetilide therapy to be initiated, a patient must be admitted to a certified hospital for at least 72 hours for cardiac monitoring. Before a hospital is a certified facility, a form verifying the completion must be on file with the company.   Dofetilide side effects Dofetilide side effects include fast or slow heart arrhythmias including torsades de pointes. The principle risk associated with dofetilide use is that it may produce a new ventricular arrhythmia, called torsades de pointes, in approximately 2% of patients taking the drug.  This arrhythmia is a life-threatening one and requires immediate treatment with withdrawal of the drug, administration of magnesium or other antiarrhythmic agents, and in some cases electrical shock treatment to restore the heart to normal rhythm.  This risk appears maximal in the first few days of drug treatment, and accordingly the drug must be initiated in a carefully monitored setting in-hospital for the first three days or so.  The risk of this particular side effect increases in patients depending on the extent of heart disease, whether there are deficiencies of potassium in the body, is more common in women than in men, and also appears to be more common in the elderly.  Certain other medicines given in combination with dofetilide may increase the blood levels of dofetilide and increase the risk of torsades also.  These medicines include verapamil, cimetidine (Tagamet®), trimethoprim, ketoconazole, prochlorperazine, and megestrol.  If you are prescribed one of these medicines, or any other drug known to prolong the QT interval on the electrocardiogram, you should consult your physician about this urgently.   Dofetilide Special Conditions To Observe Many drugs can interact with dofetilide causing excessive prolongation of the QT interval.  It is essential, therefore, that your physician prior to administration of dofetilide reviews any medicines that you are taking.   If the patient is devoid of all contraindications, dofetilide may be initiated. A repeat EKG is performed 2 to 3 hours after the first dose to assess the QTc interval. If the QTc interval has increased > 15% or if the QTc is > 500Msec (550Msec in patients with ventricular conduction abnormalities), the dose of dofetilide must be decreased. In general, the dose is halved. For the rest of the 72-hour initiation period, EKG monitoring is performed at two to three hours after each subsequent dose of dofetilide. No additional dose reductions are recommended based on QTc interval. If at any time after second dose the QTc becomes > 500Msec (550 Msec in patients with ventricular conduction abnormalities), dofetilide should be discontinued. Continuous cardiac monitoring by telemetry is continued for a minimum of 72 hours, or 12 hours after electrical or pharmacological conversion to normal sinus rhythm, whichever is greater.    A Pharmacy Services Enrollment form must be completed and faxed to Statlanders prior to patient discharge to prevent disruption of therapy. Upon discharge, patients receive a one-week supply of drug. This supply gives the patient enough medication until their mail order prescription is delivered.   Disclaimer: Information on this page is provided for general information purposes. You should not make a clinical treatment decision based on information contained in this page without consulting other references including the package insert of the drug, textbooks and where relevant, expert opinion. We cannot be held responsible for any errors you make in administering drugs mentioned on this page, nor for use of any erroneous information contained on this page.