LysaKare: Uses, Dosage & Side Effects

What Is LysaKare and What Is It Used For?

LysaKare is a sterile, clear, and colorless solution for intravenous infusion that contains two naturally occurring amino acids: L-lysine hydrochloride (25 g per litre) and L-arginine hydrochloride (25 g per litre). These amino acids are essential building blocks of proteins in the human body, but in LysaKare they serve a highly specific therapeutic purpose: protecting the kidneys during a specialized form of cancer treatment known as peptide receptor radionuclide therapy (PRRT).

PRRT is an advanced nuclear medicine treatment used for gastroenteropancreatic neuroendocrine tumours (GEP-NETs). These are tumours that arise from neuroendocrine cells in the gastrointestinal tract or pancreas. GEP-NETs are relatively rare tumours, with an estimated incidence of approximately 3.5 per 100,000 people per year globally. While many GEP-NETs are slow-growing, they can become progressive and metastasize to the liver and other organs, causing significant morbidity. A key feature of many GEP-NETs is that they overexpress somatostatin receptors (particularly subtype 2) on their cell surface, which serves as a target for both diagnostic imaging and therapeutic intervention.

The PRRT treatment involves intravenous administration of lutetium (177Lu) oxodotreotide, a radiolabeled somatostatin analogue. This compound consists of a somatostatin analogue (octreotide) that binds specifically to somatostatin receptors on the tumour cells, linked to the beta-emitting radioisotope lutetium-177 via the chelator DOTA. Once the compound binds to the somatostatin receptors on the tumour, the lutetium-177 delivers targeted radiation directly to the tumour cells, causing DNA damage and cell death. This approach allows for highly selective delivery of radiation to the tumour while sparing most normal tissues.

However, a significant challenge with PRRT is that the radiolabeled compound is also filtered by the kidneys and partially reabsorbed by the proximal renal tubular cells through a receptor-mediated endocytosis process involving the megalin and cubilin receptor system. This reabsorption leads to accumulation of the radioactive compound in the kidney parenchyma, exposing the kidneys to potentially harmful levels of radiation. Without protective measures, cumulative radiation doses from multiple PRRT cycles can cause radiation nephropathy, characterized by progressive loss of kidney function, proteinuria, and in severe cases, renal failure requiring dialysis.

This is where LysaKare plays its critical protective role. The amino acids L-lysine and L-arginine are positively charged molecules that compete with the radiolabeled somatostatin analogue for reabsorption at the proximal renal tubules through the same megalin/cubilin receptor-mediated endocytosis pathway. By flooding the tubular fluid with high concentrations of these amino acids during the period when the radioactive compound is being filtered by the kidneys, LysaKare effectively reduces the amount of radiolabeled compound that is reabsorbed and retained in the kidney cells. Clinical and preclinical studies have demonstrated that co-infusion of amino acids can reduce the kidney radiation dose by approximately 20–47%, depending on the specific protocol and patient factors.

The landmark NETTER-1 phase III randomized controlled trial, published in the New England Journal of Medicine in 2017, established the efficacy and safety of lutetium (177Lu) oxodotreotide PRRT for midgut NETs. In this trial, amino acid renal protection was a mandatory component of the PRRT protocol. The trial demonstrated a 79% reduction in the risk of disease progression or death compared with high-dose octreotide LAR alone. LysaKare was subsequently developed as a standardized, commercially available amino acid solution to ensure consistent and reliable renal protection across PRRT treatment centres, replacing the previously used compounded pharmacy preparations that varied in composition and quality.

What Should You Know Before Taking LysaKare?

Contraindications

LysaKare is contraindicated in patients with known hypersensitivity to L-lysine hydrochloride, L-arginine hydrochloride, or any of the excipients in the formulation. The solution contains hydrochloric acid and water for injections as excipients. Additionally, LysaKare should not be used in patients with severe hyperkalaemia (dangerously elevated blood potassium levels), as the amino acid infusion can further increase serum potassium concentrations, potentially leading to life-threatening cardiac arrhythmias.

Patients with severe metabolic acidosis should also not receive LysaKare, as the metabolism of the amino acids, particularly L-arginine hydrochloride, can contribute to acid production and worsen existing metabolic acidosis. In patients with severe hepatic (liver) impairment, the metabolism of amino acids may be significantly altered, and the risk of hyperammonaemia (elevated blood ammonia levels) is increased. These conditions must be carefully evaluated and corrected before proceeding with PRRT and LysaKare administration.

Warnings and Precautions

Several important warnings and precautions apply to the use of LysaKare:

• Hyperkalaemia: Both L-lysine and L-arginine are cationic amino acids that can cause transient but clinically significant increases in serum potassium levels when administered intravenously in large quantities. This occurs because the amino acids enter cells in exchange for potassium ions, which are released into the extracellular fluid. Serum potassium levels should be measured before starting the infusion, monitored during the infusion, and checked again after completion. Patients with pre-existing renal impairment, diabetes mellitus, or those taking potassium-sparing diuretics, ACE inhibitors, or angiotensin receptor blockers are at particular risk.
• Nausea and vomiting: Amino acid infusions commonly cause nausea and vomiting, which can be significant and distressing for patients. Anti-emetic premedication (such as ondansetron or granisetron) should be administered before starting the LysaKare infusion to minimize these symptoms. Severe or prolonged vomiting can lead to dehydration, electrolyte imbalances, and aspiration risk, particularly in patients who may be sedated or weakened by their underlying cancer.
• Renal impairment: Patients with pre-existing kidney disease require careful assessment before receiving LysaKare and PRRT. While LysaKare is intended to protect the kidneys, patients with already compromised renal function may be more susceptible to the electrolyte disturbances caused by the amino acid infusion, and the cumulative radiation dose from PRRT may accelerate renal deterioration. Baseline and ongoing monitoring of renal function (including glomerular filtration rate) is essential.
• Hepatic impairment: Patients with liver disease may have impaired amino acid metabolism and an increased risk of hyperammonaemia. Liver function and ammonia levels should be monitored in patients with known hepatic impairment.
• Fluid overload: Each administration involves a 1-litre infusion volume, in addition to the volume of the PRRT infusion and any concomitant hydration fluids. In patients with heart failure or compromised cardiac function, this fluid load may contribute to volume overload. The infusion rate and total fluid volume should be carefully managed in these patients.

Pregnancy and Breastfeeding

LysaKare itself, as an amino acid solution, is not expected to have direct teratogenic or harmful effects on the fetus. However, it is always administered as part of PRRT with lutetium (177Lu) oxodotreotide, which involves exposure to ionizing radiation. Ionizing radiation is known to be harmful to the developing fetus and can cause birth defects, growth retardation, intellectual disability, and childhood cancer. Therefore, PRRT (and consequently LysaKare as part of the PRRT protocol) is absolutely contraindicated during pregnancy.

Women of childbearing potential must use effective contraception during and for at least 6 months after the last PRRT treatment. A pregnancy test should be performed before each treatment cycle. Men treated with PRRT should also use effective contraception during treatment and for at least 6 months after the last dose due to the potential genotoxic effects of radiation on sperm.

Breastfeeding must be discontinued before PRRT treatment and should not be resumed after treatment, as the radiolabeled compound may be excreted in breast milk and could expose the nursing infant to harmful radiation. The decision regarding breastfeeding should be discussed with the nuclear medicine specialist and oncologist.

Driving and Operating Machinery

LysaKare itself has no or negligible direct influence on the ability to drive or operate machinery. However, the side effects of the amino acid infusion (particularly nausea, vomiting, and fatigue) and the effects of the overall PRRT procedure (which involves radiation exposure and may cause fatigue, nausea, and other systemic effects) may impair a patient’s ability to drive or operate machinery. Patients should not drive or operate heavy machinery on the day of PRRT treatment and should follow the specific guidance provided by their nuclear medicine treatment centre.

How Does LysaKare Interact with Other Drugs?

No formal pharmacokinetic drug interaction studies have been conducted with LysaKare. As a solution of naturally occurring amino acids, LysaKare is not metabolized through cytochrome P450 enzyme pathways and is not expected to cause classic pharmacokinetic drug interactions. However, there are several clinically important pharmacodynamic interactions and considerations that healthcare professionals must be aware of when administering LysaKare as part of PRRT.

The most clinically significant interaction concern relates to the hyperkalaemic effect of the amino acid infusion. Any medication that also raises serum potassium levels or impairs the body’s ability to excrete potassium can compound this effect and increase the risk of dangerous hyperkalaemia. This is particularly important because many patients with neuroendocrine tumours may be taking multiple medications for comorbid conditions.

It is important to note that the interaction with somatostatin analogues listed above relates to the PRRT treatment itself rather than to LysaKare directly. Long-acting somatostatin analogues (such as octreotide LAR or lanreotide) are commonly used as first-line treatment for GEP-NETs. These drugs occupy the same somatostatin receptors that the radiolabeled compound needs to bind to for effective treatment. Therefore, long-acting formulations are typically discontinued 4–6 weeks before PRRT to allow receptor binding sites to become available, while short-acting octreotide can be continued until 24 hours before treatment.

Additionally, any medication that affects renal function may theoretically alter the pharmacokinetics of the radiolabeled compound and the effectiveness of the amino acid renal protection. Nephrotoxic drugs should ideally be avoided in the peritreatment period to minimize cumulative kidney damage. Contrast agents used for imaging studies should be administered at least 48–72 hours before or after PRRT to avoid additional renal stress.

What Is the Correct Dosage of LysaKare?

LysaKare is administered exclusively by qualified healthcare professionals in nuclear medicine departments or specialized treatment centres equipped for PRRT. It is not a medication that patients self-administer. The dosing, timing, and infusion rate are all determined by the nuclear medicine specialist as part of the overall PRRT treatment protocol.

Adults

The recommended dose of LysaKare for adult patients undergoing PRRT is one 1-litre bag (containing 25 g of L-lysine hydrochloride and 25 g of L-arginine hydrochloride) administered as an intravenous infusion. The infusion protocol follows a specific timeline coordinated with the administration of the radiolabeled compound:

The infusion is typically administered at a rate of approximately 250 mL per hour (to deliver the full 1 litre over 4 hours), though the rate may be adjusted by the medical team based on the patient’s tolerance, particularly if nausea, vomiting, or other adverse effects occur. If the patient experiences significant nausea or vomiting despite anti-emetic premedication, the infusion rate may be temporarily reduced. In severe cases, the infusion may need to be temporarily paused, but efforts should be made to deliver the full dose to ensure adequate renal protection.

PRRT is typically administered in cycles. The standard protocol for lutetium (177Lu) oxodotreotide consists of 4 treatment cycles administered at approximately 8-week intervals. LysaKare is administered with each treatment cycle. The total treatment course therefore involves 4 separate LysaKare infusions over a period of approximately 6–8 months.

Children and Adolescents

LysaKare has not been studied in children and adolescents under 18 years of age. The safety and efficacy of LysaKare in the pediatric population have not been established, and no dosing recommendations can be made. PRRT with lutetium (177Lu) oxodotreotide is generally used in adult patients, and pediatric neuroendocrine tumours are extremely rare. Any consideration of PRRT in pediatric patients would require careful evaluation on a case-by-case basis by a multidisciplinary team including pediatric oncologists and nuclear medicine specialists.

Elderly Patients

No specific dose adjustment is required for elderly patients based on age alone. However, elderly patients are more likely to have reduced renal function, cardiovascular comorbidities, and a higher risk of electrolyte disturbances. Therefore, particular attention should be paid to monitoring renal function, serum potassium levels, and fluid balance in elderly patients receiving LysaKare. The infusion rate may need to be adjusted to accommodate reduced cardiac reserve or renal function.

Renal and Hepatic Impairment

LysaKare should be used with caution in patients with renal impairment. While the purpose of LysaKare is to protect the kidneys, patients with pre-existing renal impairment are at increased risk of hyperkalaemia and may have impaired ability to handle the additional fluid and electrolyte load. The decision to proceed with PRRT (and consequently LysaKare) in patients with significant renal impairment should be made after careful assessment of the potential benefits and risks by the nuclear medicine specialist and nephrologist.

In patients with hepatic impairment, the metabolism of the infused amino acids may be altered, and there is an increased risk of hyperammonaemia. Liver function and ammonia levels should be monitored before and after the infusion in patients with known liver disease. Mild to moderate hepatic impairment does not necessarily preclude the use of LysaKare, but severe hepatic impairment is a contraindication.

Missed Dose

Since LysaKare is administered in a hospital setting as part of a scheduled PRRT treatment, the concept of a “missed dose” in the traditional sense does not apply. If a scheduled PRRT session (and therefore the LysaKare infusion) cannot take place as planned, it should be rescheduled at the earliest appropriate opportunity, in accordance with the overall PRRT treatment schedule. The nuclear medicine specialist will determine the appropriate timing for rescheduling.

Overdose

Overdose with LysaKare could theoretically result in severe hyperkalaemia, metabolic acidosis, nausea, vomiting, and hyperammonaemia. Since LysaKare is administered under medical supervision in a controlled hospital environment, the risk of accidental overdose is low. If an overdose occurs, treatment should be symptomatic and supportive, with particular attention to monitoring and correcting serum potassium levels (including the use of potassium-lowering therapies such as insulin/glucose infusion, calcium gluconate for cardiac protection, or sodium bicarbonate if acidotic). Continuous cardiac monitoring (ECG) is recommended until potassium levels have normalized.

What Are the Side Effects of LysaKare?

Like all medicines, LysaKare can cause side effects, although not everybody gets them. It is important to note that LysaKare is always administered in conjunction with lutetium (177Lu) oxodotreotide as part of PRRT, and some side effects may be attributable to the radiolabeled compound, the radiation treatment itself, the anti-emetic premedication, or the underlying neuroendocrine tumour rather than to LysaKare alone. Distinguishing between the side effects of the different components of the treatment protocol can be challenging.

The side effects listed below are categorized according to their frequency as defined by international conventions. Your healthcare team will monitor you closely during and after each infusion to detect and manage any adverse reactions promptly.

Managing Side Effects

Nausea and vomiting are the most frequently reported side effects and are a well-known consequence of intravenous amino acid infusions. The mechanism is thought to relate to the osmotic load and the direct effects of the amino acids on the gastrointestinal system and chemoreceptor trigger zone. To minimize these symptoms, anti-emetic medications (typically 5-HT3 receptor antagonists such as ondansetron or granisetron) are administered before starting the LysaKare infusion and can be given as needed throughout the treatment session. Reducing the infusion rate may also help alleviate nausea.

Hyperkalaemia is a particularly important side effect to monitor because of the potential for serious cardiac consequences. Elevated potassium levels can cause cardiac arrhythmias, including potentially fatal ventricular tachycardia or fibrillation. The potassium-raising effect of LysaKare is usually transient and resolves within hours after the infusion is completed. However, in patients with pre-existing renal impairment or those taking potassium-raising medications, the hyperkalaemia may be more pronounced and prolonged. ECG monitoring may be indicated in high-risk patients.

If you notice any side effects not listed in this article, or if any of the side effects become severe, tell your nuclear medicine specialist or the healthcare team supervising your treatment. You can also report side effects through your national drug safety reporting system to help gather more information about the safety of this medicine.

How Should You Store LysaKare?

As LysaKare is administered exclusively in hospital settings, patients will not need to store this medication at home. However, understanding the storage requirements provides useful context about the quality and stability of the medicine you receive. The following information is primarily relevant for healthcare professionals and hospital pharmacy departments responsible for storing and preparing LysaKare.

LysaKare should be stored at temperatures not exceeding 25°C (77°F). It should be kept in the original outer carton to protect the solution from light. The medication does not require refrigeration, which simplifies storage logistics in busy hospital pharmacy departments. The shelf life of LysaKare in its unopened original packaging is 3 years from the date of manufacture, provided the storage conditions have been maintained.

Once the bag is opened or the infusion is started, LysaKare should be used immediately. The solution is intended for single use only. Any unused solution remaining in the bag after the infusion has been completed must be discarded in accordance with local regulations for the disposal of pharmaceutical waste. The solution should not be stored for later use after opening, even if it appears clear and undamaged, as sterility can no longer be guaranteed once the bag seal is broken.

Before administration, the healthcare professional will visually inspect the solution. LysaKare should be a clear, colourless solution free from visible particles. If the solution appears cloudy, discoloured, or contains particulate matter, or if the packaging appears damaged or the expiration date has passed, the bag should not be used and should be returned to the pharmacy for replacement.

What Does LysaKare Contain?

LysaKare has a deliberately simple formulation, reflecting its role as a standardized amino acid solution for renal protection. The simplicity of the formulation minimizes the risk of excipient-related adverse reactions and makes the product compatible with a wide range of patients.

Active Ingredients

L-Lysine hydrochloride (25 g per litre): L-Lysine is an essential amino acid that cannot be synthesized by the human body and must be obtained from dietary sources. In the context of LysaKare, it functions as a competitive inhibitor at the renal proximal tubule, reducing the reabsorption of radiolabeled somatostatin analogues. L-Lysine is a positively charged, basic amino acid with a molecular weight of 182.65 g/mol (as the hydrochloride salt). It has a high affinity for the megalin/cubilin receptor system in the proximal tubules, making it effective at blocking the reuptake of the radioactive compound.

L-Arginine hydrochloride (25 g per litre): L-Arginine is a semi-essential amino acid that serves multiple physiological roles, including acting as a precursor for nitric oxide, creatine, and urea. In LysaKare, it functions alongside L-lysine to provide competitive inhibition at the renal tubular level. L-Arginine hydrochloride has a molecular weight of 210.66 g/mol. Like L-lysine, it is a cationic amino acid with affinity for the megalin/cubilin receptor system. The combination of both amino acids provides synergistic renal protection compared with either amino acid alone.

Other Ingredients (Excipients)

• Hydrochloric acid (concentrated): Used for pH adjustment to ensure the solution has an appropriate pH (approximately 7.0) for intravenous administration. The amount used is minimal and is adjusted during manufacturing to achieve the target pH.
• Water for injections: The pharmaceutical-grade solvent that forms the base of the infusion solution. It meets the requirements of the European Pharmacopoeia for water for injections, ensuring sterility and freedom from pyrogens.

The solution has an osmolality of approximately 1,135 mOsmol/kg, which is hypertonic compared to normal physiological fluid (approximately 285–295 mOsmol/kg). This hypertonic nature is one reason why LysaKare is administered through a peripheral or central intravenous line at a controlled rate, to avoid local venous irritation and minimize the risk of phlebitis at the infusion site. If peripheral venous access is used, the infusion site should be monitored for signs of local irritation or extravasation.