Octreotide Acetate (Page 3 of 4)

8.2 Lactation

Risk Summary

There is no information available on the presence of octreotide acetate injection in human milk, the effects of the drug on the breastfed infant, or the effects of the drug on milk production. Studies show that octreotide administered subcutaneously passes into the milk of lactating rats; however, due to species-specific differences in lactation physiology, animal data may not reliably predict drug levels in human milk (see Data). The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for octreotide acetate injection, and any potential adverse effects on the breastfed child from octreotide acetate injection or from the underlying maternal condition.

Data

Following a subcutaneous dose (1 mg/kg) of octreotide to lactating rats, transfer of octreotide into milk was observed at a low concentration compared to plasma (milk/plasma ratio of 0.009).

8.3 Females and Males of Reproductive Potential

Discuss the potential for unintended pregnancy with premenopausal women as the therapeutic benefits of a reduction in GH levels and normalization of insulin-like growth factor 1 (IGF-1) concentration in acromegalic females treated with octreotide may lead to improved fertility.

8.4 Pediatric Use

Safety and efficacy of octreotide acetate injection in the pediatric population have not been demonstrated.

No formal controlled clinical trials have been performed to evaluate the safety and effectiveness of octreotide acetate injection in pediatric patients under age 6 years. In postmarketing reports, serious adverse events, including hypoxia, necrotizing enterocolitis, and death, have been reported with octreotide acetate injection use in children, most notably in children under 2 years of age. The relationship of these events to octreotide has not been established as the majority of these pediatric patients had serious underlying co-morbid conditions.

The efficacy and safety of octreotide acetate injection using the octreotide acetate for injectable suspension formulation was examined in a single randomized, double-blind, placebo-controlled, 6 month pharmacokinetics study in 60 pediatric patients age 6 to 17 years with hypothalamic obesity resulting from cranial insult. The mean octreotide concentration after 6 doses of 40 mg octreotide acetate for injectable suspension administered by intramuscular (IM) injection every 4 weeks was approximately 3 ng/mL. Steady-state concentrations was achieved after 3 injections of a 40-mg dose. Mean body mass index (BMI) increased 0.1 kg/m2 in octreotide acetate for injectable suspension-treated subjects compared to 0.0 kg/m2 in saline control-treated subjects. Efficacy was not demonstrated. Diarrhea occurred in 11 of 30 (37%) patients treated with octreotide acetate for injectable suspension. No unexpected adverse events were observed. However, with octreotide acetate for injectable suspension at 40 mg once a month, the incidence of new cholelithiasis in this pediatric population (33%) was higher than that seen in other adult indications such as acromegaly (22%) or malignant carcinoid syndrome (24%), where octreotide acetate for injectable suspension was 10 mg to 30 mg once a month.

8.5 Geriatric Use

Clinical studies of octreotide acetate injection did not include sufficient numbers 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. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

8.6 Renal Impairment

In patients with severe renal failure requiring dialysis, the half-life of octreotide acetate may be increased, necessitating adjustment of the maintenance dosage. [See Clinical Pharmacology (12.3)]

8.7 Hepatic Impairment-Cirrhotic Patients

In patients with liver cirrhosis, the half-life of the drug may be increased, necessitating adjustment of the maintenance dosage. [see Clinical Pharmacology (12.3)].

10 OVERDOSAGE

A limited number of accidental overdoses of octreotide acetate injection in adults have been reported. In adults, the doses ranged from 2,400 to 6,000 mcg/day administered by continuous infusion (100 to 250 mcg/hour) or subcutaneously (1,500 mcg 3 times a day). Adverse events in some patients included arrhythmia, complete atrioventricular block, hypotension, cardiac arrest, brain hypoxia, pancreatitis, hepatitis steatosis, hepatomegaly, lactic acidosis, flushing, diarrhea, lethargy, weakness, and weight loss.

If overdose occurs, symptomatic management is indicated. Up-to-date information about the treatment of overdose can often be obtained from the National Poison Control Center at 1-800-222-1222.

11 DESCRIPTION

Octreotide acetate injection, a cyclic octapeptide prepared as a clear sterile solution of octreotide, acetate salt, in a buffered lactic acid solution for administration by deep subcutaneous or IV injection. Octreotide acetate, known chemically as L-Cysteinamide, D-phenylalanyl-L-cysteinyl-L-phenylalanyl-D-tryptophyl-L-lysyl-L-threonyl-N-[2-hydroxy-1-(hydroxymethyl)propyl]-,cyclic (2 → 7)-disulfide; [R-(R*, R*)] acetate salt, is a long-acting octapeptide with pharmacologic actions mimicking those of the natural hormone somatostatin.

Octreotide acetate injection is available as sterile 1 mL single-dose vials in 2 strengths containing 100 mcg or 500 mcg octreotide (as acetate). Each single-dose vial also contains lactic acid, USP (3.4 mg), mannitol, USP (45 mg), sodium bicarbonate, USP (quantity sufficient to pH 4.2 ± 0.3), water for injection, USP (quantity sufficient to 1 mL).

Lactic acid and sodium bicarbonate are added to provide a buffered solution, pH to 4.2 ± 0.3.

The molecular weight of octreotide acetate is 1019.3 g/mol (free peptide, C49 H66 N10 O10 S2 ) and its amino acid sequence is:

octreotide-spl-structure
(click image for full-size original)

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Octreotide acetate injection exerts pharmacologic actions similar to the natural hormone, somatostatin. It is an even more potent inhibitor of GH, glucagon, and insulin than somatostatin. Like somatostatin, it also suppresses luteinizing hormone (LH) response to gonadotropin releasing hormone (GnRH), decreases splanchnic blood flow, and inhibits release of serotonin, gastrin, VIP, secretin, motilin, and pancreatic polypeptide.

By virtue of these pharmacological actions, octreotide has been used to treat the symptoms associated with metastatic carcinoid tumors (flushing and diarrhea), and VIP secreting adenomas (watery diarrhea).

12.2 Pharmacodynamics

Octreotide substantially reduces GH and/or IGF-1 (somatomedin C) levels in patients with acromegaly.

Single doses of octreotide have been shown to inhibit gallbladder contractility and to decrease bile secretion in normal volunteers. In controlled clinical trials, the incidence of gallstone or biliary sludge formation was markedly increased [see Warnings and Precautions (5.2)].

Octreotide suppresses secretion of TSH.

12.3 Pharmacokinetics

Absorption

After subcutaneous injection, octreotide is absorbed rapidly and completely from the injection site. Peak concentrations of 5.2 ng/mL (100-mcg dose) were reached 0.4 hours after dosing. Using a specific radioimmunoassay, IV and subcutaneous doses were found to be bioequivalent. Peak concentrations and area under the curve (AUC) values were dose proportional after IV single doses up to 200 mcg and subcutaneous single doses up to 500 mcg and after subcutaneous multiple doses up to 500 mcg 3 times a day (1,500 mcg/day). In patients with acromegaly, a mean peak concentration of 2.8 ng/mL (100-mcg dose) was reached in 0.7 hours after subcutaneous dosing.

Distribution

In healthy volunteers, the distribution of octreotide from plasma was rapid (tα½ = 0.2 h), the volume of distribution (Vdss ) was estimated to be 13.6 L, and the total body clearance ranged from 7 L/hr to 10 L/hr. In blood, the distribution into the erythrocytes was found to be negligible and about 65% was bound in the plasma in a concentration-independent manner. Binding was mainly to lipoprotein and, to a lesser extent, to albumin. In patients with acromegaly, the volume of distribution (Vdss ) was estimated to be 21.6 ± 8.5 L, and the total body clearance was increased to 18 L/h. The mean percent of the drug bound was 41.2%.

Elimination

The elimination of octreotide from plasma had an apparent half-life of 1.7 to 1.9 hours compared with 1 to 3 minutes with the natural hormone. The duration of action of octreotide acetate injection is variable but extends up to 12 hours depending upon the type of tumor. About 32% of the dose is excreted unchanged into the urine. In an elderly population, dose adjustments may be necessary due to a significant increase in the half-life (46%) and a significant decrease in the clearance (26%) of the drug.

In patients with acromegaly, the disposition and elimination half-lives were similar to normal subjects.

Specific Populations

Renal Impairment

In patients with mild renal impairment (CLCR 40 to 60 mL/min), octreotide t1/2 was 2.4 hours and total body clearance was 8.8 L/hr, in moderate impairment (CLCR 10 to 39 mL/min) t1/2 was 3.0 hours and total body clearance 7.3 L/hr. In patients with severe renal impairment not requiring dialysis (CLCR < 10 mL/min), octreotide t1/2 was 3.1 hours and total body clearance was 7.6 L/hr. In patients with severe renal failure requiring dialysis, total body clearance was reduced to about half that found in healthy subjects (from approximately 10 L/hr to 4.5 L/hr).

Hepatic Impairment

Patients with liver cirrhosis showed prolonged elimination of drug, with octreotide t1/2 increasing to 3.7 hr and total body clearance decreasing to 5.9 L/hr, whereas patients with fatty liver disease showed t1/2 increased to 3.4 hr and total body clearance of 8.2 L/hr.

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