Lacorene is indicated as an intravenous stimulant to the pituitary for the release of human growth hormone in patients where the measurement of pituitary reserve for HGH can be of diagnostic usefulness. It can be used as a diagnostic aid in such conditions as panhypopituitarism, pituitary dwarfism, chromophobe adenoma, postsurgical craniopharyngioma, hypophysectomy, pituitary trauma, acromegaly, gigantism and problems of growth and stature.
If the insulin hypoglycemia test has indicated a deficiency of pituitary reserve for HGH, a test with Lacorene is advisable to confirm the negative response. This can be done after a waiting period of one day. As patients may not respond to Lacorene (Arginine Hydrochloride Injection, USP) during the first test, the unresponsive patient should be tested again to confirm the negative result. A second test can be performed after a waiting period of one day. Some patients who respond to Lacorene do not respond to insulin and vice versa. The rate of false positive responses for Lacorene is approximately 32%, and the rate of false negatives is approximately 27%.
The recommended adult dose is 30 g arginine hydrochloride (300 mL of Lacorene) administered by intravenous infusion over 30 minutes. The total dose should not exceed 30 g arginine hydrochloride. See Directions for Use for preparation instructions.
The recommended pediatric dose is 0.5 g/kg arginine hydrochloride (5 mL/kg of Lacorene) administered by intravenous infusion over 30 minutes. The total dose should not exceed 30 g arginine hydrochloride.
The intravenous infusion of Lacorene is a part of the test for measurement of pituitary reserve of human growth hormone and, for successful administration of the test, clinical conditions and procedures should be as follows:
Lacorene is provided as a ready-to-use solution for patients weighing 60 kg (132 lbs) or more and should not be further diluted. For pediatric patients weighing 59 kg (130 lbs) or less a dose must be placed in a separate container. Follow the preparation instructions below.
Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit.
Withdraw a weight-based dose from an intact sealed bottle of Lacorene. The entire 300 mL bottle of Lacorene for infusion is not intended for use in patients weighing 59 kg or less. The dose must be placed in a separate container, such as an evacuated sterile glass container designed for intravenous administration, using aseptic technique.
Additionally, Lacorene is stable in polypropylene syringes and plastic containers made of either polyvinyl chloride (PVC) or ethylene vinyl acetate (EVA).
The post-penetration storage period is not more than 4 hours including infusion time at room temperature or 24 hours at refrigerated temperature (2-8°C).
The healthcare professional administering the dose should verify the accuracy of the dose prior to administration.
Use only if the solution is clear. Discard any unused drug product.
Follow these directions using aseptic technique. As Lacorene for intravenous use is provided in glass containers, a standard air-inletting, air-filtering intravenous infusion set with a bacterial air filter is required.
The administration of Lacorene is contraindicated in persons having known hypersensitivity to any ingredient in this product.
There have been reports of overdosage of Lacorene in pediatric patients leading to death. EXTREME CAUTION MUST BE EXERCISED WHEN INFUSING Lacorene INTO PEDIATRIC PATIENTS. OVERDOSAGE OF Lacorene IN PEDIATRIC PATIENTS CAN RESULT IN HYPERCHLOREMIC METABOLIC ACIDOSIS, CEREBRAL EDEMA, OR POSSIBLY DEATH.
Hypersensitivity reactions, including anaphylaxis have been reported. Appropriate medical support should be available during Lacorene administration. If anaphylaxis or other serious hypersensitivity reaction occurs, Lacorene should be discontinued and appropriate medical treatment initiated.
Lacorene should always be administered by intravenous infusion because of its hypertonicity.
Lacorene is a diagnostic aid and is not intended for therapeutic use.
Lacorene is a hypertonic (950 mOsmol/liter) and acidic (average pH of 5.6) solution that can cause irritation and damage to tissues. Care should be used to ensure administration of R-Gene 10 through a patent catheter within a patent vein. Excessive rates of infusion may result in local irritation and in flushing, nausea, or vomiting. Inadequate dosing or prolongation of the infusion period may diminish the stimulus to the pituitary and nullify the test.
The arginine in Lacorene can be metabolized resulting in nitrogen-containing products for excretion. The effect of an acute amino acid or nitrogen burden upon patients with impairment of renal function should be considered when Lacorene is to be administered.
The chloride content of R-Gene 10 is 47.5 mEq per 100 mL of solution, and the effect of infusing this amount of chloride into patients with electrolyte imbalance should be evaluated before the test is undertaken.
It should be noted that the basal and post stimulation levels of growth hormone are elevated in patients who are pregnant or are taking oral contraceptives.
Long term animal studies have not been performed to evaluate the carcinogenic potential, the mutagenic potential or the effect on fertility of intravenously administered Lacorene.
Reproduction studies have been performed in rabbits and mice at doses 12 times the human dose and have revealed no evidence of impaired fertility or harm to the fetus due to R-Gene 10 (10% Arginine Hydrochloride Injection, USP). There have been no adequate or well controlled studies for the use of Lacorene in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should not be used during pregnancy.
It is not known whether intravenous administration of Lacorene could result in significant quantities of arginine in breast milk. Systemically administered amino acids are secreted into breast milk in quantities not likely to have a deleterious effect on the infant. Nevertheless, caution should be exercised when Lacorene is to be administered to nursing women.
Clinical studies of arginine did not include a sufficient number of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.
Adverse reactions associated with 1670 infusions in premarketing studies were as follows:
Non-specific side effects consisting of nausea, vomiting, headache, flushing, numbness and local venous irritation were reported in approximately 3% of the patients.
One patient had an allergic reaction which was manifested as a confluent macular rash with reddening and swelling of the hands and face. The rash subsided rapidly after the infusion was terminated and 50 mg of diphenhydramine were administered. One patient had an apparent decrease in platelet count from 150,000 to 60,000. One patient with a history of acrocyanosis had an exacerbation of this condition following infusion of Lacorene.
The following adverse events have been reported during post-marketing use: extravasation leading to burn-like reaction and/or skin necrosis requiring surgical intervention, hypersensitivity reactions including anaphylaxis, and hematuria that in some cases occurred 1–2 days after an Lacorene administration. Because these adverse events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
An overdosage may cause a transient metabolic acidosis with hyperventilation, which could lead to death (see “ WARNINGS”). In most cases the acidosis will self-compensate and the base deficit will return to normal following completion of the infusion. If the condition persists, the deficit should be determined and corrected by a calculated dose of an alkalizing agent.