Two drugs in this class are now available – Prandin, derived from benzoic acid and approved by the FDA in 1997, and Starlix, derived from D-phenylalanine and approved in 2000. They raise insulin levels rapidly by stimulating the beta cells by mechanisms different from the sulfonylureas. They enhance insulin release from the pancreas over a short period of time only when the glucose level is high. Therefore, the risk of hypoglycemia is reduced. Their activity more closely mimics normal first-phase insulin release when food is eaten by a person without diabetes. Peak activity is seen in one hour and the short action time of three hours makes them ideal for matching carbs in meals.
| Rapid Insulin Releasers Target Organ: pancreas Action: Increases first phase insulin release, glucose driven, lowers after-meal glucose Lowers HbA1c by 0.5% to 2.0% Time to reach maximum effect: 1 hr Taken: Starlix is taken right before each meal while Prandin is taken 15 – 30 minutes before each meal |
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|---|---|---|---|
| Drug | Acts Over | Dose Range | Doses/Day |
| Prandin (repaglinide) |
3 hrs | 0.5 – 4 mg before each meal |
2 – 3 |
| Starlix (nateglinide) |
3 hrs | 60 – 120 mg before each meal |
2 – 3 |
| Side Effects: low blood sugar, nausea, vomiting, diarrhea, muscle aches, upper respiratory infection, cold and flu-like symptoms, headache, joint aches, and back pain | |||
| Contraindications: Type 1 diabetes, liver disease | |||
Prandin or Starlix are taken 10 to 15 minutes before meals and do not need to be taken if a meal is skipped. Like sulfonylureas, they do not work in Type 1 diabetes and work in Type 1.5 and Type 2 only as long as the beta cells are capable of producing insulin.
People who eat carbs and then have their blood sugars spike more than 40 or 50 mg/dl above their pre-meal readings are the most likely to benefit from these drugs. However, most people do not check to see how high their blood sugar is spiking after eating. Testing at one or two hours after a meal is of real value because it can identify those who may benefit from one of these drugs. One minor inconvenience of the drug is the need to remember to take it several times a day before meals.
In people who retain residual insulin production, one of these medications can be combined with a basal insulin like NPH, Levemir, or Lantus to provide great control. The injected insulin provides basal coverage to keep the fasting blood sugar at a good level, while one of the rapid insulin releasers can enhance internal insulin release to control the blood sugar after meals.
Interactions with other drugs may occur, so be sure your physician knows what else you are taking. Certain drugs may increase the effect of these medications, including large doses of aspirin or Motrin type medications, sulfonamides, chloramphenicol, coumadins, monoamine oxidase inhibitors, and probenecid. Drugs that may decrease their effect include calcium channel blockers, corticosteroids, oral contraceptives, thiazide diuretics, thyroid preparations, estrogens, phenothiazines, phenytoin, rifampin, isoniazid, phenobarbital, and sympathomimetics. One advantage of the medications is that they can be taken safely by people with impaired kidney function or sulfa allergies.