Wednesday, May 5, 2010

About the Medicines Used for Diabetes

The information in this blog is rather technical and probably boring for someone who doesn't have diabetes. However, if you are on any type of medication for diabetes I recommend that you at least read about the medicines you are taking. It is important to be knowledgable about what you are taking into your body, so that you can be aware of what is helping and what may be causing a problem.

Type 1 diabetes is always treated with insulin. Without insulin, a person with type 1 will develop hyperglycemia that progresses to ketoacidosis, and eventually death. They are usually given a long acting insulin that is given in shots once or twice a day, depending on the type, and then supplement it with short acting insulin at mealtime to cover the amount of carbohydrates they eat. There are various brands and types of long-acting and short-acting insulin, and sometimes they are put together in one shot. The combination shot may work for some people with type 2 diabetes, but I don't recommend it for type 1.

Type 1 diabetics now have the option of using an insulin pump, which keeps a more steady flow of insulin. However, they often still may need to give extra short acting insulin to cover their meals.

Often I have heard doctors tell type 1 diabetics that they can eat what they want; just cover the amount of carbohydrates with adequate insulin. However, if type 1 diabetics eat high carbohydrate meals or eat too much so that they need large amounts of insulin, eventually their cells become resistant to insulin and they also develop type 2 diabetes. High levels of insulin also increase fat deposition and increase inflammation in the body, which increases hardening of the arteries, heart disease and stroke risk. I believe that it is very important for all diabetics to watch what they eat, and recommend the Sugar Stabilization Program given later in this book.

Type 2 diabetes is usually treated with oral medications, unless it advances to a level where they no longer work, and then insulin is given.

Please read the following carefully if you are taking oral medications for diabetes. Make sure the medication you are taking is not causing you serious side effects.

The various types of oral medications can be catagorized as follows:

Sulfonylureas. Sulfonylureas used to be the first medication to be prescribed for type 2 diabetes. However, with the newer drugs, they are usually now added after the other drugs are not giving enough control. Sulfonylureas lower blood sugar by stimulating the pancreas to release more insulin. The first drugs of this type that were developed -- Dymelor, Diabinese, Orinase and Tolinase -- are not as widely used since they tend to be less potent, have more side effects, and are shorter-acting drugs than the newer sulfonylureas. They include Glucotrol, Glucotrol XL, DiaBeta, Micronase, Glynase PresTab, and Amaryl. These drugs can cause a decrease in the hemoglobin A1c (HbA1c) of up to 1%-2%.

Sulfonylureas often induce hypoglycemia (low blood sugar) which often prevents a diabetic from achieving good glucose control; people usually keep their blood glucose elevated above optimal in order to reduce the frequency and severity of hypoglycemia, which can cause coma.

Like insulin, sulfonylureas can induce weight gain, which increases problems associated with diabetes. Other side-effects can be abdominal upset, headache and hypersensitivity reactions.

Sulfonylureas are potentially harmful to the fetus and should not be used in pregnancy or in patients who may become pregnant. Impairment of liver or kidney function increase the risk of hypoglycemia, and are contraindications.

The use of sulfonylurea agents has been reported, but not proven in all studies, to increase the risk of death from heart and blood vessel disease, probably because they cause an increase in insulin levels. Patients with diabetes are already more likely to have these problems, but they should be aware that many of these drugs make heart disease worse. However, glyburide (Micronase, Diabeta and Glynase) and gliclazide (Glipizide) have been shown in studies to have a positive effect on heart and blood vessel disease.

Biguanides. Metformin (Glucophage, Glucophage XR, Riomet, Fortamet and Glumetza) is the most commonly used oral diabetic agent, and actually originates from the French lilac (Galega officinalis), a plant known for several centuries to reduce the symptoms of elevated blood sugar.
Metformin works by reducing glucose production by the liver (gluconeogenesis). The "average" person with type 2 diabetes has three times the normal rate of gluconeogenesis; metformin treatment reduces this by over one third. Metformin also causes the cells to become more sensitive to insulin, increasing glucose uptake by the cells and therefore lowering blood sugar. Meformin can decrease the HbA1c 1%-2%. It also increases fatty acid oxidation, which reduced triglyceride and LDL cholesterol levels.

Unlike other diabetic medications, metformin does not cause low blood sugar, one of the most dangerous side effects of most medications. It has a lower side effect profile than the other drugs.

The most common side effect is gastrointestinal upset, including diarrhea, cramps, nausea, vomiting, and increased flatulence. GI upset happens most often at the beginning of use, or when the dose is increased. It is better to start low and slowly increase.

Metformin should not be used in people who have kidney damage or heart failure because of the risk of precipitating a severe build up of acid (called lactic acidosis) in these patients, which can cause death.

Thiazolidinediones. These diabetes pills improve insulin's effectiveness (improving insulin resistance) in muscle and in fat tissue. They lower the amount of sugar released by the liver and make fat cells more sensitive to the effects of insulin. Rosiglitazone (Avandia) and Pioglitazone (Actos) are the two drugs of this class. A decrease in the HbA1c of 1%-2% can be seen with this class of oral diabetes medications.

These drugs may take a few weeks before they have an effect in lowering blood sugar.
The main side effect of all thiazolidinediones is water retention, leading to edema, generally a problem in less than 5% of individuals, but a big problem for some and potentially, with significant water retention, leading to congestive heart failure. Therefore, thiazolidinediones should be prescribed with both caution and patient warnings about the potential for water retention/weight gain, especially in patients with decreased ventricular function (NYHA grade III or IV heart failure).

Recent studies have shown there may be an increased risk of coronary heart disease and heart attacks with rosiglitazone.

Pioglitazone treatment, in contrast, has shown significant protection from both micro- and macro-vascular cardiovascular events and plaque progression.

Alpha-glucosidase inhibitors, including Precose and Glyset. These drugs block enzymes that help digest starches, slowing the rise in blood sugar. These diabetes pills may cause diarrhea or gas. They can lower hemoglobin A1c by 0.5%-1%.

Meglitinides, including Prandin and Starlix. These diabetes medicines lower blood sugar by stimulating the pancreas to release more insulin. The effects of these diabetes pills depend on the level of glucose. They are said to be glucose dependent. High sugars make this class of diabetes medicines release insulin. This is unlike the sulfonylureas that cause an increase in insulin release, regardless of glucose levels, and can lead to hypoglycemia.

However, these medications can still cause hypoglycemia to some degree. They can also cause weight gain because of the increased levels of insulin.

Dipeptidyl peptidase IV (DPP-IV) inhibitors, including sitagliptin (Januvia). Januvia works to lower blood sugar in patients with type 2 diabetes by increasing insulin secretion from the pancreas and reducing sugar production. These diabetes pills increase insulin secretion when blood sugars are high. They also signal the liver to stop producing excess amounts of sugar. DPP-IV inhibitors control sugar without causing weight gain, and often reduces appetite. The medication may be taken alone or with other medications such as metformin.

Side effects include headache, nausea, diarrhea or constipation, sore throat and respiratory tract infections. More rare but serious side effects include fever and a headache with a severe blistering, peeling red rash. Many report an increase in joint pain. The FDA has warned of serious pancreatitis that can lead to death.

Incretin mimetics. Exanitide (Byetta) is a new class of medication approved in 2005. Byetta is administered as a subcutaneous injection (under the skin) of the abdomen, thigh, or arm, 30 to 60 minutes before the first and last meal of the day. It is a synthetic version of exendin-4, a hormone found in the saliva of the Gila monster. It enhances the glucose-dependent secretion of insulin, suppresses glucagon secretion, and slows gastric emptying. It supposedly reduces appetite and assists with weight loss.
The main side effects of Byetta use are gastrointestinal in nature, including acid or sour stomach, belching, diarrhea, heartburn, indigestion, nausea, and vomiting. Other side effects include dizziness, headache, and feeling jittery. The FDA has issued a warning about severe pancreatitis that can lead to death associated with Byetta.

Combination therapy. There are several combination diabetes pills that combine two medications into one tablet. One example of this is Glucovance, which combines glyburide (a sulfonylurea) and metformin. Others include Metaglip, which combines glipizide (a sulfonylurea) and metformin, and Avandamet which utilizes both metformin and rosiglitazone (Avandia) in one pill.

When blood sugars are not able to be controlled with oral medication, a person with type 2 diabetes may also be placed on insulin.

The next blog will be about diets used for diabetes, including my Sugar Stabilization Program.

Until we meet again,
Dr. Judi

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