Improvement of acromegaly after octreotide LAR treatment

Octreotide is a somatostatin analog that inhibits growth hormone release showing higher potency than natural somatostatin so it has proved to be effective in acromegaly treatment. The objective of present study was to establish the effects of octreotide LAR (long acting release) preparation in patients with active acromegaly. The following parameters were assessed: clinical response, safety of medication, GH and IGF-1 serum concentrations and pituitary tumor size. Eleven patients (6 men and 5 women) range 41.4 years old with diagnosis of active acromegaly were included. Octreotide was administered at 0.1 mg subcutaneusly dose three times daily for four weeks to test the drug tolerability. Afterwards patients received octreotide LAR 20 mg intramuscularly separated by 28 days periods with an option to continue for 8 months. Basal average GH serum concentrations was 27.6 ng/mL. After 6 months treatment reduction to 5.03 +/- 5.38 ng/mL in 9 patients (p < 0.001) was observed. Basal IGF-1 average serum concentration was 889.55 +/- 167.29 ng/mL with a reduction value to 483.00 +/- 239.71 ng/mL in 9 of 11 patients after 6 months treatment (p < 0.005). The drug was well tolerated with few adverse effects Diarrhea, flatulence and steatorrhea were observed during the administration of subcutaneous octreotide in 18.2% of patients. Two patients had symptomatic biliary lithiasis that was successfully removed by surgery. Clinical symptoms improved and some of them dissapeared such as headaches and sweatings. Tumor shrinkage was observed in 66.7% of cases. Monthly injections of 20 mg of octreotide LAR were effective to reduce GH and IGF-1 levels in patients with active acromegaly accompanied by improvement of clinical symptoms and significant tumor size reduction.