Uses for flecainide

Flecainide is used to prevent or treat irregular heartbeats (arrhythmias) such as paroxysmal supraventricular tachycardia (PSVT) and paroxysmal atrial fibrillation/flutter (PAF). Flecainide is also used to prevent life-threatening sustained ventricular tachycardia (sustained VT).

Flecainide belongs to the group of medicines known as antiarrhythmics. It works directly on the heart tissue and will slow the nerve impulses in the heart. This helps keep the heart rhythm normal.

There is a chance that flecainide may cause new or make worse existing heart rhythm problems when it is used. Since it has been shown to cause severe problems in some patients, it is only used to treat serious heart rhythm problems. Discuss this possible effect with your doctor.

This medicine is available only with your doctor's prescription.

Before using flecainide

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of flecainide in the pediatric population. Safety and efficacy have not been established, but your doctor may choose to use this medication in children with serious heart rhythm problems

Geriatric

No information is available on the relationship of age to the effects of flecainide in elderly patients. However, elderly patients are more likely to have age-related kidney problems, which may require an adjustment in the dose for patients receiving flecainide.

Breast Feeding

Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

• Bepridil
• Cisapride
• Dronedarone
• Levoketoconazole
• Levomethadyl
• Mesoridazine
• Nirmatrelvir
• Pimozide
• Piperaquine
• Ritonavir
• Saquinavir
• Sparfloxacin
• Terfenadine
• Thioridazine
• Tipranavir
• Vernakalant
• Ziprasidone

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Acecainide
• Adagrasib
• Ajmaline
• Alfuzosin
• Amiodarone
• Amisulpride
• Amitriptyline
• Amoxapine
• Anagrelide
• Apomorphine
• Aprindine
• Arbutamine
• Aripiprazole
• Aripiprazole Lauroxil
• Arsenic Trioxide
• Artemether
• Asenapine
• Astemizole
• Azimilide
• Azithromycin
• Bedaquiline
• Bendroflumethiazide
• Boceprevir
• Bretylium
• Buprenorphine
• Bupropion
• Buserelin
• Ceritinib
• Chloral Hydrate
• Chloroquine
• Chlorothiazide
• Chlorpromazine
• Chlorthalidone
• Ciprofloxacin
• Citalopram
• Clarithromycin
• Clofazimine
• Clomipramine
• Clothiapine
• Clozapine
• Cobicistat
• Crizotinib
• Cyclobenzaprine
• Dabrafenib
• Darifenacin
• Dasabuvir
• Dasatinib
• Degarelix
• Delamanid
• Delavirdine
• Desipramine
• Deslorelin
• Deutetrabenazine
• Dexmedetomidine
• Dibenzepin
• Disopyramide
• Dofetilide
• Dolasetron
• Domperidone
• Donepezil
• Droperidol
• Duloxetine
• Efavirenz
• Encorafenib
• Enflurane
• Entrectinib
• Erythromycin
• Escitalopram
• Etravirine
• Fedratinib
• Fexinidazole
• Fingolimod
• Fluconazole
• Fluoxetine
• Formoterol
• Foscarnet
• Fostemsavir
• Gatifloxacin
• Gemifloxacin
• Glasdegib
• Gonadorelin
• Goserelin
• Granisetron
• Halofantrine
• Haloperidol
• Halothane
• Histrelin
• Hydrochlorothiazide
• Hydroflumethiazide
• Hydroquinidine
• Hydroxychloroquine
• Hydroxyzine
• Ibutilide
• Iloperidone
• Imipramine
• Inotuzumab Ozogamicin
• Isoflurane
• Isradipine
• Ivabradine
• Ivosidenib
• Ketoconazole
• Lacosamide
• Lapatinib
• Lefamulin
• Lenvatinib
• Leuprolide
• Levofloxacin
• Lidocaine
• Lidoflazine
• Lofexidine
• Lorcainide
• Lumefantrine
• Macimorelin
• Mefloquine
• Methadone
• Methotrexate
• Metolazone
• Metronidazole
• Mifepristone
• Mirtazapine
• Mobocertinib
• Moxifloxacin
• Nafarelin
• Nilotinib
• Norfloxacin
• Nortriptyline
• Octreotide
• Ofloxacin
• Ombitasvir
• Ondansetron
• Osilodrostat
• Osimertinib
• Oxaliplatin
• Ozanimod
• Pacritinib
• Paliperidone
• Panobinostat
• Paritaprevir
• Pasireotide
• Pazopanib
• Peginterferon Alfa-2b
• Pentamidine
• Phenobarbital
• Pimavanserin
• Pirmenol
• Pitolisant
• Polythiazide
• Ponesimod
• Posaconazole
• Prajmaline
• Prilocaine
• Primidone
• Probucol
• Procainamide
• Prochlorperazine
• Promethazine
• Propafenone
• Protriptyline
• Quetiapine
• Quinidine
• Ranolazine
• Relugolix
• Ribociclib
• Risperidone
• Selpercatinib
• Sematilide
• Sertindole
• Sertraline
• Sevoflurane
• Simeprevir
• Siponimod
• Sodium Phosphate
• Sodium Phosphate, Dibasic
• Sodium Phosphate, Monobasic
• Solifenacin
• Sorafenib
• Sotalol
• Spiramycin
• Sulfamethoxazole
• Sulpiride
• Sultopride
• Sunitinib
• Tacrolimus
• Tedisamil
• Telaprevir
• Telavancin
• Telithromycin
• Tetrabenazine
• Toremifene
• Trazodone
• Trichlormethiazide
• Triclabendazole
• Trifluoperazine
• Trimethoprim
• Trimipramine
• Triptorelin
• Vandetanib
• Vardenafil
• Vemurafenib
• Venlafaxine
• Vilanterol
• Vinflunine
• Voclosporin
• Voriconazole
• Zolmitriptan
• Zotepine
• Zuclopenthixol

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Cimetidine
• Digoxin
• Paroxetine
• Propranolol
• Semaglutide
• Verapamil

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

• Milk

Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

• AV block (type of abnormal heart rhythm), with no pacemaker or
• Bundle branch block (heart rhythm problem), with no pacemaker or
• Cardiogenic shock (shock caused by heart attack) or
• Chronic atrial fibrillation or
• Heart attack, recent—Should not be used in patients with these conditions.

• Congestive heart failure (severe) or
• Heart disease (e.g., cardiomyopathy) or
• Sick sinus syndrome (type of abnormal heart rhythm)—Use with caution. May make these conditions worse.

• Electrolyte imbalance (e.g., high or low potassium in the blood)—Should be corrected first before using this medicine.

• Kidney disease or
• Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

• If you have a permanent pacemaker—Use with caution. Flecainide may interfere with the pacemaker and require more careful follow-up by the doctor.

Proper use of flecainide

In some cases, you will receive your first dose of this medicine in a hospital. Your doctor will watch you closely after you take this medicine to make sure you do not have any serious side effects.

Take this medicine exactly as directed by your doctor even though you may feel well. Do not take more medicine than your doctor ordered.

This medicine may be taken with or without food.

This medicine works best when there is a constant amount in the blood. To help keep this amount constant, do not miss any doses. Also, it is best to take the doses 12 hours apart, in the morning and at night, unless otherwise directed by your doctor. If you need help in planning the best times to take your medicine, check with your doctor.

In infants (less than 2 years of age) who drink a lot of milk, your doctor may adjust the dose of this medicine when it is time to reduce the amount of milk your infant is receiving, or if they develop gastroenteritis. Talk with your doctor if you have questions about this.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage form (tablets):
  • For paroxysmal supraventricular tachycardia (PSVT) and paroxysmal atrial fibrillation/flutter (PAF):
    • Adults—At first, 50 milligrams (mg) every 12 hours. Your doctor may increase your dose as needed.
    • Children—Use and dose must be determined by your doctor. Dose is based on body size and must be determined by your child's doctor. The starting dose is 100 milligrams (mg) per square meter (m[2]) per day for infants 6 months and older and 50 mg/m(2) per day in infants younger than 6 months. Doses are divided into two or three equal doses per day.
  • For sustained ventricular tachycardia (sustained VT):
    • Adults—At first, 100 milligrams (mg) every 12 hours. Your doctor may increase your dose as needed. However, the dose is usually not more than 400 mg per day.
    • Children—Use and dose must be determined by your doctor. Dose is based on body size and must be determined by your child's doctor. The starting dose is 100 milligrams (mg) per square meter (m[2]) per day for infants 6 months and older and 50 mg/m(2) per day in infants younger than 6 months. Doses are divided into two or three equal doses per day.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions while using flecainide

It is important that your doctor check your progress at regular visits to make sure the medicine is working properly. This will allow for changes to be made in the amount of medicine you are taking, if necessary.

Check with your doctor right away if you develop any of the following: chest pain; shortness of breath; swelling of your hands, ankles, or feet; or weight gain. These may be symptoms of heart failure.

This medicine can cause changes in your heart rhythm, such as conditions called PR, QRS, or QT prolongation. It may cause fainting or serious side effects in some patients. Contact your doctor right away if your symptoms do not improve or if they become worse.

Your doctor may want you to carry a medical identification card or bracelet stating that you are using this medicine.

Before having any kind of surgery (including dental surgery) or emergency treatment, tell the medical doctor or dentist in charge that you are taking this medicine.

Flecainide may cause some people to become dizzy, lightheaded, or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert.

If you have been using this medicine regularly for several weeks, do not suddenly stop using it. Check with your doctor for the best way to gradually reduce the amount you are taking before stopping completely.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Side Effects of flecainide

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

• Difficult or labored breathing
• dizziness, fainting, or lightheadedness
• fast, irregular, pounding, or racing heartbeat or pulse
• shortness of breath
• tightness in the chest
• wheezing

Less common

• Burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
• chest pain
• fainting
• feeling of warmth
• fever
• increased sweating
• partial or slight paralysis
• redness of the face, neck, arms, and occasionally, upper chest
• shakiness and unsteady walk
• shakiness in the legs, arms, hands, or feet
• swelling of the feet or lower legs
• trembling or shaking of the hands or feet
• unsteadiness, trembling, or other problems with muscle control or coordination

Rare

• Arm, back, or jaw pain
• black, tarry stools
• bleeding gums
• blood in the urine or stools
• blurred vision
• chest discomfort
• chest tightness or heaviness
• chills
• confusion
• convulsions
• cough
• decrease in the frequency of urination
• decrease in urine volume
• difficulty in passing urine (dribbling)
• difficulty with breathing
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• frequent urination
• general feeling of discomfort or illness
• headache
• increased volume of pale, dilute urine
• nausea
• nervousness
• noisy breathing
• painful or difficult urination
• pinpoint red spots on the skin
• pounding in the ears
• sensation of pins and needles
• slow or fast heartbeat
• sore throat
• sores, ulcers, or white spots on the lips or in the mouth
• stabbing pain
• sweating
• swollen glands
• thickening of bronchial secretions
• troubled breathing
• unusual bleeding or bruising
• unusual tiredness or weakness
• yellow eyes or skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

• Blurred vision or seeing spots

Less common

• Abdominal or stomach pain
• acid or sour stomach
• anxiety or mental depression
• belching
• constipation
• continuing ringing or buzzing or other unexplained noise in the ears
• depression
• diarrhea
• feeling of constant movement of self or surroundings
• general feeling of discomfort or illness
• hearing loss
• heartburn
• indigestion
• lack or loss of strength
• loss of appetite
• sensation of spinning
• sleepiness or unusual drowsiness
• sleeplessness
• skin rash
• stomach discomfort, upset, or pain
• trouble with sleeping
• unable to sleep
• weight loss

Rare

• Bloated
• change in color vision
• change in taste
• cracks in the skin
• decreased awareness or responsiveness
• decreased interest in sexual intercourse
• difficulty seeing at night
• difficulty with moving
• dry mouth
• excess air or gas in the stomach or intestines
• eye pain or irritation
• false or unusual sense of well-being
• feeling of unreality
• full feeling
• hair loss or thinning of the hair
• hives or welts
• inability to have or keep an erection
• increased sensitivity of the eyes to sunlight
• itching skin
• joint pain
• lack of feeling or emotion
• loss in sexual ability, desire, drive, or performance
• loss of heat from the body
• loss of memory
• muscle aching or cramping
• muscle pain or stiffness
• passing gas
• problems with memory
• red, swollen skin
• scaly skin
• sense of detachment from self or body
• severe sleepiness
• swollen joints
• swollen lips, mouth, or tongue
• uncaring uncontrolled eye movements

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.