Peripheral treatments, though they do not address the causes of hormonal hypersecretion, may provide beneficial relief of the symptoms of carcinoid syndrome. In this section, you will find information about the following treatments:
- Antidiarrheal Agents
- Other Peripheral Treatments
Antidiarrheal Agents
A variety of different pharmacologic agents have been used to treat severe diarrhea. Antidiarrheals can be divided into 3 main categories, depending on their mode of action: antimotility agents, adsorbent agents, and antisecretory agents. Some examples of these types of agents are listed below.
Antimotility Agents1,2
- Reduce propulsive activity of the gut and thus reduce stool frequency and volume in most patients2
- Slow transit time (contact between intraluminal contents and the intestinal mucosa increases), thereby enhancing the potential for absorption2
- Potential risk of addiction if severe diarrhea is chronic and the agent must be used for prolonged periods1
Adsorbent Agents1
- Nonspecific agents that act by binding intraluminal contents through surface adhesion
- Generally, do not require a prescription
- Indicated for symptomatic relief and may have limited value in chronic severe diarrhea
- Bind intraluminal contents indiscriminately—toxins, digestive secretions, nutrients, and drugs
Antisecretory Agents1
- Decrease the flow of fluids and electrolytes into the bowel
- Contain ingredients that are toxic at high doses
- Excipients such as salicylates can cause nausea, vomiting, and tinnitus, and can interfere with blood coagulation
- Poses a risk for toxicity at high doses
Bacterial Replacement Agents1
- Used for treating and preventing diarrhea
- Some agents have not been studied during pregnancy and breast-feeding, so their safety is unknown
- Lactobacillus from supplements that contain live bacteria might grow too well in patients with weakened immune systems
INDICATIONS AND USAGE
Sandostatin® LAR Depot (octreotide acetate for injectable suspension) is indicated for patients in whom initial treatment with immediate release Sandostatin® (octreotide acetate) Injection has been shown to be effective and tolerated for:
- Long-term maintenance therapy in acromegalic patients who have had inadequate response to surgery and/or radiotherapy or for whom surgery and/or radiotherapy is not an option (the goal of treatment in acromegaly is to reduce GH and IGF-1 levels to normal).
- Long-term treatment of the severe diarrhea and flushing episodes associated with metastatic carcinoid tumors.
- Long-term treatment of the profuse watery diarrhea associated with VIP-secreting tumors.
In patients with carcinoid syndrome and VIPomas, the effect of Sandostatin Injection and Sandostatin LAR Depot on tumor size, rate of growth and development of metastases has not been determined.
IMPORTANT SAFETY INFORMATION
Warnings and Precautions:
- Gallbladder abnormalities may occur: Patients should be monitored periodically.
- Glucose Metabolism: Hypoglycemia or hyperglycemia may occur. Blood glucose levels should be monitored when Sandostatin LAR Depot treatment is initiated or when the dose is altered. Antidiabetic treatment should be adjusted accordingly.
- Thyroid Function: Hypothyroidism may occur. Baseline and periodic assessment of thyroid function (TSH, total and/or free T4) is recommended.
- Cardiac Function: Bradycardia, arrhythmia, conduction abnormalities, and other EKG changes may occur. The relationship of these events to octreotide acetate is not established because many of these patients have underlying cardiac disease. Use with caution in at-risk patients.
- Nutrition: Octreotide may alter absorption of dietary fats. Monitoring of vitamin B12 levels is recommended during therapy with Sandostatin LAR Depot. Patients on total parenteral nutrition (TPN) and octreotide should have periodic monitoring of zinc levels.
Drug Interactions: The following drugs require monitoring and possible dose adjustment when used with Sandostatin LAR Depot: cyclosporine, insulin, oral hypoglycemic agents, beta-blockers, bromocriptine. Octreotide has been associated with alterations in nutrient absorption, so it may have an effect on absorption of orally administered drugs. Drugs mainly metabolized by CYP3A4 and which have a low therapeutic index should be used with caution.
Adverse Reactions: The most common adverse reactions occurring in patients receiving Sandostatin LAR Depot are:
- Acromegaly: biliary abnormalities (52%), diarrhea (36-48%), cholelithiasis (13-38%), abdominal pain or discomfort (11-29%), flatulence (26%), influenza-like symptoms (20%), constipation (19%), headache (15%), anemia (15%), hyperglycemia (15%), injection site pain (2-14%), hypertension (13%), dizziness (12%), fatigue (11%), nausea (10%), vomiting (7%), hypothyroidism (2%), hypoglycemia (2%), and goiter (2%).
- Carcinoid Tumors and VIPomas: biliary abnormalities (62%), injection site pain (20-50%), nausea (24-41%), abdominal pain (10-35%), fatigue (8-32%), headache (16-30%), hyperglycemia (27%), back pain (8-27%), constipation or vomiting (15-21%), dizziness (18-20%), sinus bradycardia (19%), pruritus (18%), URTI (10-18%), myalgia (4-18%), flatulence (9-16%), arthropathy (8-15%), rash (15%), generalized pain (4-15%), sinusitis (5-12%), conduction abnormalities (9%), hypoglycemia (4%), and arrhythmia (3%).
