Effect of the somatostatin analogue octreotide acetate on hemostasis in humans

Sandostatin causing reversible thrombocytopenia

Esophageal variceal bleeding can be serious or life threatening. Drug-induced thrombocytopenia can further complicate such bleeding episodes. Thrombocytopenia because of sandostatin has been reported in the literature only once previously. We describe a case of sandostatin-induced reversible thrombocytopenia with a positive rechallenge. Platelet count decreased during administration of sandostatin and recovered only when the infusion was halted. The proposed mechanism of thrombocytopenia during both episodes is immunologic. Physician awareness of sandostatin-induced thrombocytopenia can prevent unnecessary complication during episodes of esophageal variceal bleeding and is rapidly reversed with discontinuation of the drug.

Long-acting octreotide as rescue therapy in chronic bleeding from gastrointestinal angiodysplasia

BACKGROUND

Octreotide has shown to be effective against rebleeding from gastrointestinal angiodysplasias, but a long-term daily parenteral administration is recommended. Long-acting octreotide (LAR-OCT) could overcome such a limitation, but it has not been studied extensively.

AIM

To investigate the usefulness of long-acting octreotide in the control of chronic bleeding from gastrointestinal angiodysplasias.

METHODS

Thirteen patients with chronic gastrointestinal bleeding because of angiodysplasias were enrolled. Diagnosis was made by endoscopy and wireless video capsule. Long-acting octreotide was administered intramuscularly at a dosage of 10 mg/monthly for 1 year. Patients were followed up for a minimum period of 1 year, and haemoglobin levels, blood transfusions, iron supplementation and hospitalizations were recorded 1 year before and after starting long-acting octreotide therapy.

RESULTS

Follow-up ranged from 12 to 60 months. Nine of 13 patients (69%) did not need blood transfusions and iron supplementation any longer; a partial improvement was observed in one patient; no effect was found in the others. No side effect was recorded in any patient.

CONCLUSIONS

Long-acting octreotide for 1 year may be beneficial as a rescue therapy for controlling chronic bleeding from gastrointestinal angiodysplasias in patients not eligible for surgery. Its monthly administration represents an advantage, which makes such a formulation the choice when a long-term treatment is mandatory.

Loss of endothelial glycocalyx during acute hyperglycemia coincides with endothelial dysfunction and coagulation activation in vivo

Hyperglycemia is associated with increased susceptibility to atherothrombotic stimuli. The glycocalyx, a layer of proteoglycans covering the endothelium, is involved in the protective capacity of the vessel wall. We therefore evaluated whether hyperglycemia affects the glycocalyx, thereby increasing vascular vulnerability. The systemic glycocalyx volume was estimated by comparing the distribution volume of a glycocalyx permeable tracer (dextran 40) with that of a glycocalyx impermeable tracer (labeled erythrocytes) in 10 healthy male subjects. Measurements were performed in random order on five occasions: two control measurements, two measurements during normoinsulinemic hyperglycemia with or without N-acetylcysteine (NAC) infusion, and one during mannitol infusion. Glycocalyx measurements were reproducible (1.7 +/- 0.2 vs. 1.7 +/- 0.3 l). Hyperglycemia reduced glycocalyx volume (to 0.8 +/- 0.2 l; P < 0.05), and NAC was able to prevent the reduction (1.4 +/- 0.2 l). Mannitol infusion had no effect on glycocalyx volume (1.6 +/- 0.1 l). Hyperglycemia resulted in endothelial dysfunction, increased plasma hyaluronan levels (from 70 +/- 6 to 112 +/- 16 ng/ml; P < 0.05) and coagulation activation (prothrombin activation fragment 1 + 2: from 0.4 +/- 0.1 to 1.1 +/- 0.2 nmol/l; d-dimer: from 0.27 +/- 0.1 to 0.55 +/- 0.2 g/l; P < 0.05). Taken together, these data indicate a potential role for glycocalyx perturbation in mediating vascular dysfunction during hyperglycemia.

Thrombocytopenia associated with octreotide

A 42-year-old woman with a history of hepatitis C-induced cirrhosis, gastrointestinal bleeding, and alcohol abuse presented to the hospital with hematemesis and melena. Based on our previous experience, octreotide (Sandostatin) therapy was started at 50 mg/hr and continued for 5 days. Platelet count on admission (122 x 10(9)/L) dropped immediately after octreotide therapy was started; upon discontinuation, platelet count began trending up from 72 x 10(9)/L. However, octreotide was not suspected at this point as the cause of thrombocytopenia. In a subsequent admission, octreotide was again administered with a resultant prompt decrease in platelet count. To our knowledge, this is only the second case report of octreotide-induced thrombocytopenia, and the first case of this adverse effect demonstrated by inadvertent rechallenge.