Samsca

Samsca is used to treat hyponatremia (low sodium in the blood) in patients with heart failure or syndrome of inappropriate antidiuretic hormone (SIADH).

Sodium is a chemical that the body needs to be able to function well. If you have a low sodium blood level, your body will not function normally and you may not feel well. 

Samsca works in the kidneys to help maintain the right amount of sodium for the body. This medicine is available only with your doctor's prescription.This product is available in the following dosage forms:

• Tablet

Before using Samsca, you must know all about the risks and complications associated with it. 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 Population: Appropriate studies have not been performed on the relationship of age to the effects of tolvaptan in the pediatric population. Safety and efficacy have not been established.

Geriatric Population: Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of tolvaptan in the elderly.

Pregnancy: All Trimesters: Category C: Animal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.

Breastfeeding: There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions: 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.

• Atazanavir
• Boceprevir
• Clarithromycin
• Cobicistat
• Conivaptan
• Delavirdine
• Idelalisib
• Imatinib
• Indinavir
• Itraconazole
• Ketoconazole
• Nefazodone
• Nelfinavir
• Posaconazole
• Ritonavir
• Saquinavir
• Telaprevir
• Telithromycin
• Tipranavir
• Voriconazole

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.

• Amobarbital
• Amprenavir
• Aprepitant
• Butabarbital
• Carbamazepine
• Ceritinib
• Dabrafenib
• Diltiazem
• Efavirenz
• Eliglustat
• Erythromycin
• Fluconazole
• Fosamprenavir
• Fosaprepitant
• Fosphenytoin
• Lomitapide
• Lumacaftor
• Modafinil
• Nevirapine
• Nilotinib
• Oxcarbazepine
• Pentobarbital
• Phenobarbital
• Phenytoin
• Pioglitazone
• Piperaquine
• Rifabutin
• Rifampin
• Rifapentine
• Secobarbital
• Simeprevir
• St John's Wort
• Tocophersolan
• Verapamil
• Vincristine
• Vincristine Sulfate Liposome

Other Interactions: 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.

• Grapefruit Juice

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:

• Alcoholism, chronic
• Cirrhosis (a liver disease) 
• Liver disease, severe 
• Malnutrition (poor nutrition or undernourished condition)—May increase risk for more serious side effects.
• Anuria (not able to pass urine) 
• Hypovolemic hyponatremia (low blood sodium with low blood fluid) 
• Kidney disease, severe 
• Not able to sense or respond to thirst 
• Patients with sodium blood levels must be increased right away—Should not be used in patients with these conditions
• Dehydration 
• Hyperkalemia (high potassium in the blood) 
• Hypovolemia (low blood volume) 
• Stomach or bowel bleeding—Use with caution. May make these conditions worse

To use Samsca properly, you must follow all instructions given by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

It is important that you should take your first dose or restart your treatment with this medicine in a hospital. This will allow your doctor to check your response to this medicine and monitor any unwanted problems that may occur.

This medicine should come with a Medication Guide. Read and follow these instructions carefully. Ask your doctor if you have any questions. You may take this medicine with or without food.

This medicine is not for long-term use. You should not take this medicine for more than 30 days to lessen your risk of having a liver injury.

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 hyponatremia:
  • Adults—At first, 15 milligrams (mg) once a day. Your doctor will adjust your dose as needed. However, the dose is usually not more than 60 mg per day.
  • Children—Use and dose must be determined by your doctor.

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.

Before using Samsca, there are some precautions you must take. It is very important that your doctor checks your progress at regular visits.

This will allow your doctor to see if the medicine is working properly and to decide if you should continue to use it. Blood tests may be needed to check for unwanted effects.

You should not use Samsca together with: 

• clarithromycin (Biaxin®)
• indinavir (Crixivan®)
• itraconazole (Sporanox®)
• ketoconazole (Nizoral®)
• nefazodone (Serzone®)
• nelfinavir (Viracept®)
• ritonavir (Norvir®)
• saquinavir (Fortovase®, Invirase®)
• telithromycin (Ketek®)

Using these medicines together may increase the risk for more serious side effects.

Check with your doctor right away if you have drowsiness, confusion, mood changes, muscle weakness in the arms or legs, seizures (convulsions), or trouble with speaking, swallowing, or controlling body movements. 

These may be symptoms of a serious and rare condition called osmotic demyelination syndrome (ODS). This may occur if the sodium blood level rises too fast.

Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, vomiting, or yellow eyes or skin. These could be symptoms of a serious liver problem.

Certain medicines or illnesses, such as vomiting or diarrhea, may cause you to lose too much body water (dehydration). If you think you are dehydrated, tell your doctor right away. Always have water available to drink if you are thirsty unless your doctor tells you otherwise.

Ask your doctor first before you use any medicine or salt substitutes that contain potassium. You should not eat grapefruit or drink grapefruit juice while you are taking this medicine. Grapefruit or grapefruit juice may increase the effects of tolvaptan in your body.

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 (eg, St. John's wort) or vitamin supplements.

As with many medications, there are several potential side effects associated with Samsca. 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:

• abdominal or stomach pain
• blurred vision
• dry mouth
• flushed, dry skin
• frequent urination
• fruit-like breath odor
• increased hunger
• increased thirst
• increased urination
• increased volume of pale, dilute urine
• nausea
• sweating
• thirst
• troubled breathing
• unexplained weight loss
• unusual tiredness or weakness
• vomiting

Less common:

• abdominal or stomach tenderness
• anxiety
• blood in the urine
• bloody stools
• blue lips, fingernails, or skin
• bruising
• chest pain
• confusion
• cough
• coughing or vomiting blood
• dark-colored urine
• dizziness or lightheadedness
• fainting
• fast, slow, irregular or shallow heartbeat
• fever
• irregular, fast or slow, or shallow breathing
• loss of consciousness
• muscle cramps or spasms
• muscle pain or stiffness
• pain, redness, or swelling in the arm or leg
• persistent bleeding or oozing from puncture sites, mouth, or nose
• pink or red urine
• rash
• rectal bleeding
• shortness of breath
• sudden shortness of breath or troubled to breathe
• sweating
• vaginal bleeding

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:

• difficulty having a bowel movement (stool)
• lack or loss of strength

Less common:

• loss of appetite
• weight loss

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.