The Food & Drug Administration approved pramlintide (Symlin, Amylin Pharmaceuticals) injection recently as an adjunct treatment in patients with Type 1 or Type 2 diabetes who use mealtime insulin and have failed to achieve desired glucose control despite optimal insulin therapy.
Diabetes affects over 18 million Americans and is rising at three times the rate of population growth. Of this total, approximately 4.5 million use insulin.
Pramlintide is a synthetic analog of human amylin, a neuroendocrine hormone. Unlike most insulin products, pramlintide will be available only by prescription. The product will be commercially available in approximately 90 days.
"What absolutely stands out is that preprandial doses of rapid- or short-acting insulin must initially be cut by 50% because of the risk of hypoglycemia," said Cameron C. Lindsey, Pharm.D., BC-ADM, an assistant professor of pharmacy practice at the University of Missouri-Kansas City School of Pharmacy. "It is absolutely essential that pharmacists emphasize this to patients."
The company recommends adjusting subsequent insulin doses to optimize glycemic control once the target dose of pramlintide is achieved and nausea (if experienced) has subsided. The manufacturer strongly urges that the patient make insulin and pramlintide dose adjustments only as directed by a healthcare professional.
Pramlintide and insulin should always be administered as separate injections, and pramlintide should not be mixed with any type of insulin, cautioned Lindsey. Amylin said that if a dose of pramlintide is missed, an additional injection should not be given, and patients should always use new syringes and needles to administer pramlintide and insulin injections.
Lindsey explained that patients who take pramlintide must be very motivated regarding their care. They should recognize the symptoms of hypoglycemia and know how to treat it, and know when to follow up with their pharmacist or other healthcare professional based on their glucose readings.
Amylin warned that pramlintide is not for patients who have poor compliance with their current insulin regimen and with their prescribed blood glucose monitoring; who have a glycosylated hemoglobin (HbA1c) value >9%; who have experienced recurrent severe hypoglycemia requiring assistance within the past six months; who are unaware of the symptoms of hypoglycemia; have a confirmed diagnosis of gastroparesis; who require the use of drugs to stimulate gastrointestinal motility; and who are pediatric patients.
The recommended initial dose of pramlintide in those with Type 2 diabetes is 60 mcg. This dose should be increased to 120 mcg as tolerated. The dose should be increased to 120 mcg when no clinically significant nausea has occurred for three to seven days.
In those with Type 1 diabetes, the recommended initial dose of pramlintide is 15 mcg. This dose should be titrated at 15-mcg intervals to a maintenance dose of 30 mcg or 60 mcg as tolerated. Doses should be increased to the next increment when no clinically significant nausea has occurred for at least three days.
Amylin urged patients to contact their healthcare professional weekly to review pramlinitide and insulin dose adjustments until the target dose of pramlintide is reached, pramlintide is well tolerated, and blood glucose concentrations are stable.
"The safe use of pramlintide requires a lot of precautions," Lindsey concluded. "Pharmacists need to take an active role in educating patients about its proper use and in working with physicians to titrate medications as needed."