Clinical data | |
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Routes of administration | Oral or intravenous administration IV |
Pharmacokinetic data | |
Bioavailability | Oral administration 85% [1] |
Protein binding | 10% [2] |
Metabolism | Hepatic |
Elimination half-life | 4.3–15.1 h [2] |
Excretion | Renal |
Identifiers | |
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CAS Number | |
PubChem CID | |
ChemSpider | |
UNII | |
KEGG | |
ChEBI | |
ChEMBL | |
CompTox Dashboard (EPA) | |
ECHA InfoCard | 100.151.497 |
Chemical and physical data | |
Formula | C15H23N3O2 |
Molar mass | 277.368 g·mol−1 |
3D model (JSmol) | |
Density | 1.1±0.1 g/cm3 g/cm3 |
Melting point | 138–140 °C (280–284 °F) |
Boiling point | 465–535 °C (869–995 °F) |
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Acecainide (N-acetylprocainamide, NAPA) is an antiarrhythmic drug. Chemically, it is the N-acetylated metabolite of procainamide. It is a Class III antiarrhythmic agent, whereas procainamide is a Class Ia antiarrhythmic drug. It is only partially as active as procainamide; when checking levels, both must be included in the final calculation.
In the early 1930s, Claude Beck was undertaking pioneer cardiac surgery at the Lakeside Hospital in Cleveland, Ohio. During and after his surgery he was facing problems with arrhythmias. These problems were investigated by Frederick R. Mautz. In these experiments he used drugs similar to cocaine, because these drugs were readily absorbed from mucous membranes and were also known to have some effect on the myocardium. Mautz tried procaine, but its action was short-lived owing to digestion by esterases. From procaine Mautz synthesized procainamide, which is not a substrate for esterases. Procainamide has the additional advantage of being active by mouth. Procainamide was approved by the US FDA on June 2, 1950 under the brand name Pronestyl. In 1951 Pronestyl was launched by Bristol-Myers Squibb, a pharmaceutical company in the US. Along with the discovery of procainamide came the discovery of its metabolite acecainide. [3]
Procainamide is metabolized in the liver to acecainide by N-acetyltransferase, an enzyme that is genetically determined. [4] N-Acetyltransferase is an enzyme that catalyzes the transfer of acetyl groups from acetyl-CoA to arylamines and aromatic amines such as procainamide. [5]
This reaction is known as an acetylation reaction, that refers to the process of introducing an acetyl group (resulting in an acetoxy group) into a compound, namely the substitution of an acetyl group for an active hydrogen atom.
Acecainide is the major metabolite of the antiarrhythmic drug, procainamide. Measurements of procainamide in serum may not accurately reflect the drug's complete pharmacologic activity in the body. Monitoring acecainide levels along with the procainamide is recommended during procainamide therapy. Acecainide is considered comparable in activity to its parent compound; however, acecainide levels will vary widely. Serum levels of acecainide increase in patients on chronic procainamide therapy, particularly in those with renal impairment. The average serum concentration ratio of acecainide to procainamide is 0.8 to 1.2, depending on a genetically determined tendency to acetylate procainamide rapidly or slowly. Because the ratio varies from patient to patient, measuring serum acecainide and procainamide together helps to achieve an optimum anti-arrhythmic effect and reduce the risk of toxicity. [6]
Acecainide is a potassium-channel blocker like Class III antiarrhythmic compounds. This compounds can bind to potassium channels and delays phase 3 repolarization. These electrophysiological changes decrease the sensitiveness of cells to electrical stimuli, which leads to an increase in action potential duration and an increase in the effective refractory period. By increasing the effective refractory period NAPA is very useful in suppressing tachyarrhythmias caused by re-entry ventricular arrhythmia. [7] In this way NAPA can increase the Q - T interval of the PQRST heart rhythm. [8]
Acecainide is pharmacologically active as an antiarrhythmic agent. It has electrophysiological effects of a class III antiarrhythmic drug and it is used as a medicine to increase the Q – T interval of the PQRST heart rhythm in patients with cardiac arrhythmias. The equivalent drug procainamide, which is a class Ia antiarrhythmic drug, is also used in patients with cardiac arrhythmias. [8] Nevertheless, NAPA does only affect the Q - T interval, while procainamide has also effect on the QRS-interval. [9] Also the electrophysiologic properties of NAPA are a little bit different from those of procainamide and NAPA is not completely effective for suppressing ventricular dysrhythmias, but its antiarrhythmic mechanisms are similar to those of procainamide. [10]
The pharmacokinetic properties of acecainide, an active metabolite of procainamide, have been studied in healthy people and patients with cardiomyopathy in elderly and younger patients. In healthy people, mean peak plasma concentrations following oral doses of 900 and 1000 mg of NAPA were 5.9 and 5.3 mg/L, and it attained 2.2 to 2.8 hours after administration. In a few patients with cardiomyopathy the mean peak plasma concentration was 5.6 mg/L 1.6 hours after ingestion. Acecainide has a bioavailability of 85%, with a mean peak plasma occurring between 45 and 90 minutes. [11]
The mean apparent volume of distribution range is from 2.61 to 2.9 L/kg in healthy people and patients with cardiomyopathy. At steady state, the volume of distribution is 1.3 to 1.7 L/kg in healthy subjects, 1.3 to 1.58 L/kg in patients with coronary artery disease, and 1.25 L/kg in patients with ventricular arrhythmias receiving acecainide therapy. [11]
Acecainide has a volume of distribution of 1.5 L/kg that is less than the Vd of procainamide (2.0 L/kg). Also it binds 10% less to proteins than procainamide. Because of this low volume of distribution, it can be concluded that the medicine is thought to be confined in the plasma or liquid parts of the blood. [12] [13]
In the body, acecainide is metabolised in several products. Some acecainide can convert to procainamide. The deacetylation clearance of acecainide is 0.39 L/h compare to a total NAPA clearance of 1.38 L/h, indicating that 2.8% of NAPA was converted to procainamide, 0.3% was desethylated, and 10.3% convert to unidentified metabolites, with 86.6% excreted unchanged. Following oral administration, 59 to 87% of a dose of acecainide is excreted unchanged in the urine. [11]
Renal clearance of acecainide following short and long term administration ranges from 2.08±0.36 mL/min/kg to 3.28±0.52 mL/min/kg in healthy people. There is a linear relationship between acecainide clearance and creatinine clearance. [2]
However, the clearance of acecainide was reduced in a few patients with cardiomyopathyand and ventricular arrhythmias. Also is excretion of procainamide and NAPA is reduced in patients with CKD. [14] A major reaction to procainamide and several other drugs is a syndrome that closely resembles lupus. A reactive metabolite, possibly nitrosoprocainamide is thought to play a role in the lupus reaction. Acecainide, unlike procainamide, appears not to form a reactive metabolite.
Mean plasma elimination half-lives in healthy subjects range from 6.8 to 9.6 hours following single or repeated doses when sampling times of 12 to 24 hours are used. A tendency for prolongation of half-lives was noted in patients with cardiomyopathy and in patients with arrhythmias. [11]
Steady-state procainamide and acecainide concentrations were used to compute procainamide clearance and acecainide/procainamide (NAPA/PA) concentration ratio. Using stepwise multiple linear regression age, creatinine clearance and congestive heart failure were found to influence procainamide clearance significantly (p less than 0.05). Age and creatinine clearance effected the NAPA/PA concentration ratio (p less than 0.05). Based on this data, age appears to have an independent effect on both procainamide clearance and the NAPA/PA ratio that is separate from the decline in renal function that occurs in elderly patients. [15]
It can be given either intravenously or orally, and is eliminated primarily by renal excretion. Comparative studies with other antiarrhythmic drugs have not been undertaken apart from a small study in atrial flutter where NAPA was better than quinidine plus digoxin. Although further clinical experience is required before the relative place of acecainide in therapy can be determined, the drug nevertheless appears to offer advantages over procainamide, particularly with respect to the reduced formation of antinuclear antibodies.
The dose of acecainide should be adjusted to control the patients’ arrhythmias and with regard to their clinical state including age, renal function and concurrent administration of other drugs. There appears to be an overlap in plasma concentrations required for therapeutic efficacy and those associated with adverse effects. Rapid bolus infusion of acecainide has been associated with serious hypotension and a maximum infusion rate of 50 mg/min has been suggested. [11]
Intravenous infusion of 0.45 mg/kg/min for 30 minutes, followed by 0.22 mg/mL/min for 30 minutes and a maintenance infusion, suppressed more than 90% of PVCs. Doses of acecainide 15 to 20 mg/kg were also effective in preventing induced ventricular tachycardia or prolonging ventricular tachycardia cycle length and reducing frequency of PVCs. However, the dosage required to maintain antiarrhythmic effects is still not clear. [11]
In short-term and more prolonged studies, acecainide 1.5 to 2.0 g as a single dose or as three or four divided doses a day appears to be satisfactory in controlling PVCs. In patients who are refractory to other antiarrhythmic agents, the doses required appear to be greater. Moreover, a few studies inferred that tolerance may develop with long-term administration of NAPA, necessitating increased doses. There are no specific dosage recommendations for patients with left ventricular dysfunction, although care should be taken to reduce the dose in patients with moderate to severe renal dysfunction. [11]
The loading dose of this medicine is 15–18 mg/kg administered over 30 to 60 minutes for people without insufficient renal function or decreased cardiac output and 12 mg/kg for people with this disorders. This can also be described by the formula of the loading dose:
LD = Vss(l/kg) × IBW(kg) × Cp(mg/L) / ( S x F)
The daily empiric oral dose can be calculated by the next formula:
Daily dose = (Css)ave × Cl × 1440 / ( S x F )
This those is decreased by 25% in patients with heart and/or liver failures, and it is decreased by 50% by patients with renal failures. [11]
Research shows that accumulation of acecainide during procainamide therapy can alter both procainamide elimination as well as its electrophysiologic actions. [9] A few healthy people demonstrated that concomitantly administered trimethoprim decreased the renal clearance of procainamide and formed NAPA, resulting in increased plasma concentrations of both drugs and increases in QTc after procainamide. Trimethoprim, procainamide and acecainide are all excreted by active tubular secretion. Also amiodarone, cimetidine and trimethoprim increase the NAPA serum level. Cimetidine and ranitidine possibly increase plasma procainamide and NAPA concentrations and subsequent toxicity. [11] Furthermore, alcohol enhances acetylation of procainamide to NAPA and alcohol consumption may reduce half-life. [16] It also has been shown that coadministration of para-aminobenzoic acid decreases the biotransformation of procainamide to acecainide in a patient with rapid acetylation kinetics. [4]
Measuring the ratio of acecainide and procainamide concentrations together helps to achieve an optimum anti-arrhythmic effect and reduce the risk of toxicity. [6]
acecainide can cause cardiac toxicity that effects in torsades de pointes. Also acecainide can decrease renal function when it is accumulated during a procainamide therapy. Furthermore, acecainide can lead to a low blood pressure and a serious left ventricle depression when it is present in toxic concentrations. [12] Other common side effects of NAPA are gastrointestinal disturbances, insomnia, dizziness, lightheadedness, blurred vision, numbness and tingling sensation. [13] [17] There has been a large resemblance reported between the concentration range associated with arrhythmic suppression of acecainide and the range of concentrations where intolerable side effects begin to develop. No severe cardiac toxicity has been notified with oral intake despite plasma concentrations as high as 40 micrograms/mL. However, hypotension has been reported in association with a rapid injection of acecainide. [2]
In animals, acecainide has positive inotropic effects, but it also causes negative chronotropic and hypotensive activity. [12] The cardiovascular pharmacodynamics of procainamide and NAPA have not been well identified in small rodents without the presence of anesthesia or restraint. Researchers are trying to make models of the effects of procainamide and acecainide in animals. [18]
1-Aminobenzotriazole (ABT) is a nonselective inhibitor of cytochrome P450 enzymes, but recent research confirmed that this inhibitor also inhibit the RLS9-catalyzed N-acetylation of procainamide. In rats oral ABT decreases the clearance of intravenous procainamide for 45%, followed by a decreased acecainide-to-procainamide ratio in urine and plasma. Studies in humans also shows that ABT is an inhibitor of N-acetyltransfersase. These studies claim that ABT is a more potent inhibitor of N-acetyltransferase 2 compared with N-acetyltransferase 1. [19]
Furosemide is a loop diuretic medication used to treat edema due to heart failure, liver scarring, or kidney disease. It had many trade names including Discoid, Frusemide, Lasix and Uremide. Furosemide may also be used for the treatment of high blood pressure. It can be taken intravenously or orally. When given intravenously, furosemide typically takes effect within five minutes; when taken orally, it typically metabolizes within an hour.
Dofetilide is a class III antiarrhythmic agent. It is marketed under the trade name Tikosyn by Pfizer, and is available in the United States in capsules containing 125, 250, and 500 µg of dofetilide. It is not available in Europe or Australia.
Amiodarone is an antiarrhythmic medication used to treat and prevent a number of types of cardiac dysrhythmias. This includes ventricular tachycardia (VT), ventricular fibrillation (VF), and wide complex tachycardia, as well as atrial fibrillation and paroxysmal supraventricular tachycardia. Evidence in cardiac arrest, however, is poor. It can be given by mouth, intravenously, or intraosseously. When used by mouth, it can take a few weeks for effects to begin.
Flecainide is a medication used to prevent and treat abnormally fast heart rates. This includes ventricular and supraventricular tachycardias. Its use is only recommended in those with dangerous arrhythmias or when significant symptoms cannot be managed with other treatments. Its use does not decrease a person's risk of death. It is taken by mouth or injection into a vein.
Oxiracetam is a nootropic drug of the racetam family and a very mild stimulant. Several studies suggest that the substance is safe even when high doses are consumed for a long period of time. However, the mechanism of action of the racetam drug family is still a matter of research. Oxiracetam is not approved by Food and Drug Administration for any medical use in the United States.
Procainamide (PCA) is a medication of the antiarrhythmic class used for the treatment of cardiac arrhythmias. It is a sodium channel blocker of cardiomyocytes; thus it is classified by the Vaughan Williams classification system as class Ia. In addition to blocking the INa current, it inhibits the IKr rectifier K+ current. Procainamide is also known to induce a voltage-dependent open channel block on the batrachotoxin (BTX)-activated sodium channels in cardiomyocytes.
Azimilide is a class ΙΙΙ antiarrhythmic drug. The agents from this heterogeneous group have an effect on the repolarization, they prolong the duration of the action potential and the refractory period. Also they slow down the spontaneous discharge frequency of automatic pacemakers by depressing the slope of diastolic depolarization. They shift the threshold towards zero or hyperpolarize the membrane potential. Although each agent has its own properties and will have thus a different function.
Acebutolol, sold under the brand names Sectral among others, is a beta blocker for the treatment of hypertension and arrhythmias. Acebutolol is a cardioselective beta-1 blocker and has intrinsic sympathetic activity. It is commonly used in the treatment of angina.
Bisoprolol, sold under the brand name Zebeta among others, is a beta blocker medication used for heart diseases. This includes tachyarrhythmias, high blood pressure, chest pain from not enough blood flow to the heart, and heart failure. It is taken by mouth.
Gidazepam, also known as hydazepam or hidazepam, is a drug which is an atypical benzodiazepine derivative, developed in the Soviet Union. It is a selectively anxiolytic benzodiazepine. It also has therapeutic value in the management of certain cardiovascular disorders.
Mexiletine (INN) is a medication used to treat abnormal heart rhythms, chronic pain, and some causes of muscle stiffness. Common side effects include abdominal pain, chest discomfort, drowsiness, headache, and nausea. It works as a non-selective voltage-gated sodium channel blocker and belongs to the Class IB group of anti-arrhythmic medications.
Ibutilide is a Class III antiarrhythmic agent that is indicated for acute cardioconversion of atrial fibrillation and atrial flutter of a recent onset to sinus rhythm. It exerts its antiarrhythmic effect by induction of slow inward sodium current, which prolongs action potential and refractory period of myocardial cells. Because of its Class III antiarrhythmic activity, there should not be concomitant administration of Class Ia and Class III agents.
Prajmaline (Neo-gilurythmal) is a class Ia antiarrhythmic agent which has been available since the 1970s. Class Ia drugs increase the time one action potential lasts in the heart. Prajmaline is a semi-synthetic propyl derivative of ajmaline, with a higher bioavailability than its predecessor. It acts to stop arrhythmias of the heart through a frequency-dependent block of cardiac sodium channels.
Lorcainide is a Class 1c antiarrhythmic agent that is used to help restore normal heart rhythm and conduction in patients with premature ventricular contractions, ventricular tachycardiac and Wolff–Parkinson–White syndrome. Lorcainide was developed by Janssen Pharmaceutica (Belgium) in 1968 under the commercial name Remivox and is designated by code numbers R-15889 or Ro 13-1042/001. It has a half-life of 8.9 +- 2.3 hrs which may be prolonged to 66 hrs in people with cardiac disease.
Delorazepam, also known as chlordesmethyldiazepam and nordiclazepam, is a drug which is a benzodiazepine and a derivative of desmethyldiazepam. It is marketed in Italy, where it is available under the trade name EN and Dadumir. Delorazepam (chlordesmethyldiazepam) is also an active metabolite of the benzodiazepine drugs diclazepam and cloxazolam. Adverse effects may include hangover type effects, drowsiness, behavioural impairments and short-term memory impairments. Similar to other benzodiazepines delorazepam has anxiolytic, skeletal muscle relaxant, hypnotic and anticonvulsant properties.
Efonidipine (INN) is a dihydropyridine calcium channel blocker marketed by Shionogi & Co. of Japan. It was launched in 1995, under the brand name Landel (ランデル). The drug blocks both T-type and L-type calcium channels. Drug Controller General of India (DCGI) has approved the use of efonidipine in India. It is launched under the brand name "Efnocar".
Landiolol (INN) is an ultra short-acting, β1-superselective intravenous adrenergic antagonist, which decreases the heart rate effectively with less negative effect on blood pressure or myocardial contractility. In comparison to other beta blockers, landiolol has the shortest elimination half-life, ultra-rapid onset of effect, and predictable effectiveness with inactive metabolites. The pure S-enantiomer structure of landiolol is believed to develop less hypotensive side effects in comparison to other β-blockers. This has a positive impact on the treatment of patients when reduction of heart rate without decrease in arterial blood pressure is desired. Landiolol was developed by modifying the chemical structure of esmolol to produce a compound with a higher rate of cardioselectivity and a greater potency without increasing its duration of action. It is sold as landiolol hydrochloride. Based on its positive benefit risk profile, landiolol has been granted the marketing authorization and introduced to the European markets under the brand names Rapibloc, Raploc, Runrapiq, Landibloc mid 2016. Landiolol is available in Japan under the brand names Onoact (50 mg) and Corbeta.
Celivarone is an experimental drug being tested for use in pharmacological antiarrhythmic therapy. Cardiac arrhythmia is any abnormality in the electrical activity of the heart. Arrhythmias range from mild to severe, sometimes causing symptoms like palpitations, dizziness, fainting, and even death. They can manifest as slow (bradycardia) or fast (tachycardia) heart rate, and may have a regular or irregular rhythm.
Voclosporin, sold under the brand name Lupkynis, is a calcineurin inhibitor used as an immunosuppressant medication for the treatment of lupus nephritis. It is an analog of ciclosporin that has enhanced action against calcineurin and greater metabolic stability.
QT prolongation is a measure of delayed ventricular repolarisation, which means the heart muscle takes longer than normal to recharge between beats. It is an electrical disturbance which can be seen on an electrocardiogram (ECG). Excessive QT prolongation can trigger tachycardias such as torsades de pointes (TdP). QT prolongation is an established side effect of antiarrhythmics, but can also be caused by a wide range of non-cardiac medicines, including antibiotics, antidepressants, antihistamines, opioids, and complementary medicines. On an ECG, the QT interval represents the summation of action potentials in cardiac muscle cells, which can be caused by an increase in inward current through sodium or calcium channels, or a decrease in outward current through potassium channels. By binding to and inhibiting the “rapid” delayed rectifier potassium current protein, certain drugs are able to decrease the outward flow of potassium ions and extend the length of phase 3 myocardial repolarization, resulting in QT prolongation.