Samsca (Tolvaptan)

Description

Samsca (Tolvaptan) is a medication prescribed to help people with low sodium levels in their blood. It works by blocking certain receptors in the body that are affected by a hormone called vasopressin, which helps control water and sodium levels. By doing this, Tolvaptan can help treat conditions like hyponatremia, where sodium levels drop too low and can be dangerous. This drug is often used for patients with heart failure or a condition known as SIADH, where the body makes too much vasopressin. Additionally, Tolvaptan can slow down the progress of a genetic kidney disease called autosomal dominant polycystic kidney disease (ADPKD).

Directions

Samsca is typically started in a hospital setting to ensure serum sodium levels can be monitored accurately. It is taken orally, with the starting dose usually being 15 mg once daily. The dosage may be increased to 30 mg once daily after at least 24 hours if the body tolerates the drug well and additional treatment is necessary. The medication's effectiveness depends on closely following these dosage guidelines. It is important to avoid a rapid increase in serum sodium levels; changes should not exceed 12 mEq/L over 24 hours to reduce the risk of serious complications.

Ingredients

The active ingredient in Samsca is Tolvaptan.

Contraindications

Avoid taking or using this medication if any of the following apply:

• Autosomal dominant polycystic kidney disease (ADPKD) outside of FDA-approved Risk Evaluation and Mitigation Strategy (REMS) programs
• An inability to adequately respond to feelings of thirst
• Hypovolemic hyponatremia.
• Concurrent use with strong CYP3A inhibitors
• Anuria (inability to produce urine)
• Known hypersensitivity to Tolvaptan or any of the medication’s ingredients

Cautions

• Before taking Samsca, tell your healthcare provider if you have:
• Any existing health conditions
• Any allergies
• A list of all medications you are currently taking
• Whether you are pregnant or breastfeeding

• Treatment with Samsca should be limited to 30 days to reduce the risk of liver injury. If signs of liver damage occur, stop using Samsca and consult a healthcare provider. Samsca is not recommended for patients with existing liver disease.
• Dehydration or low blood volume may occur and may require medical attention. Stay hydrated and inform your doctor of any symptoms like dizziness or excessive thirst.
• Samsca should not be used with hypertonic saline solutions. Discuss all medications and treatments with your healthcare provider.
• Avoid using Samsca with medications that strongly or moderately inhibit CYP3A enzymes, as these may cause harmful interactions.
• Serum potassium levels should be monitored in patients with high potassium levels or those taking medications that increase potassium. Report any symptoms of high potassium, such as muscle weakness or irregular heartbeat.
• Adequate urinary output must be ensured before starting Samsca. Inform your doctor if you have any urinary difficulties.

Side Effects

Samsca may cause side effects such as thirst, dry mouth, weakness, constipation, and increased urination. Some people may also notice elevated blood sugar levels. These side effects are typically mild, but you should inform your doctor if they persist or worsen during treatment.

Samsca can raise blood sodium levels too quickly, increasing the risk of a serious condition called osmotic demyelination syndrome (ODS), which can lead to symptoms like confusion, trouble speaking or swallowing, seizures, or muscle weakness. Liver problems, including severe liver failure, are also possible and require immediate attention if symptoms like jaundice, dark urine, or right upper stomach pain occur. Always follow your healthcare provider's instructions closely, and avoid stopping or restarting Samsca without medical supervision.

References

1. Samsca (Tolvaptan) Product Monograph. Tokyo, Japan: Otsuka Pharmaceutical Co., Ltd.; 2021.
2. Samsca (Tolvaptan) Drug Label Information. Tokyo, Japan: Otsuka Pharmaceutical Co., Ltd.; 2022.

About Dr. Gerardo Sison (Page Author)

An honors graduate of the University of Florida, Dr. Sison started his pharmacy career in a community setting, extending his services to hospitals and clinics over time. He has also worked in medication therapy management, advising patients on proper medication use for their chronic health conditions. Read More....