If your pt is taking insulin, find out which kind of insulin they are taking. Sulfonylureas are a major class of drugs used for diabetics. Biguanides are also used. Thiaolidinediols have had some problems associated with them. Alpha-glucosidase inhibitors are newer medications used.
3% of the general population is diabetic, although this is an underestimate. Diabetes is the number one metabolic disorder in the world. Uncontrolled diabetes mellitus is a major cardiovascular risk factor. Tight control of glucose concentration has been shown to delay the onset of some complications (retinopathy, nephropathy, coronary artery disease, arterioscerosis)… the term “tight control” is argued vigorously. If you’re fasting and have a blood sugar of 90-100 mg/dL we can call this controlled, the target for control of a diabetic pt does not mean that they’re trying to get the blood glucose from 250 to 90 or 100… the goal is to get it as low as you can with proper diet and exercise. Like HTN, you don’t absolutely push to get things back to optimal normal levels. Type I diabetics, no matter how well controlled, have a significantly shorter life expectancy than those of the type II class; there is thus some other pathology going on aside from the aberration in glucose metabolism. MDs must try to manage not only hypoglycemia but damage to organ systems.
Type I is a quick onset, as opposed to Type II, which comes on in later life. Type I diabetes is treated by insulin (primary tx), diet and exercise. Type II diabetes is treated by oral hypoglycemic agents – sulfonylureas (the gold std, because of cost effectiveness), metformin (Glucophage) (very effective, able to alter insulin receptor and alter the glucose transporter), acarbose, insulin, diet, weight reduction, and exercise. Combining metformin with another drug such as sulfonylureas is effective.
Troglitazone (Rezulin) HAS BEEN WITHDRAWN due to toxicity.
As determined by the glucose tolerance test, in type 1 diabetics the plasma glucose is greatly elevated at all time and the plasma insulin concentration is essentially nondetectable. In type 2 diabetics plasma glucose concentration is elevated at all time points and the plasma insulin response to an oral glucose tolerance test is delayed by prolonged. Total insulin response is normal or increased. In early type 2 diabetes (glucose intolerance) the plasma insulin concentration is elevated and secretion is exaggerated.
It is recommended to schedule a diabetic pt in the morning, because if they have just eaten breakfast they will have enough glucose in their blood. However, the most important thing is that the pt is taking his/her meds and that they are controlled.
The most serious condition we’ll encounter with these drugs is hypoglycemia. If the dose isn’t properly adjusted or if the pt doesn’t have a meal to maintain appropriate blood levels, hypoglycemic shock is always the fear. It may manifest as nervousness, sweatiness, dizziness and agitation, and you might want to blame it on other things when what is happening is that the pts blood sugar levels are dropping. If there’s other drugs like beta-blockers (propanolol, et al.) on board that block those responses, they mask the symptoms of the emerging hypoglycemia.
Insulin action is on carbohydrate and lipid metabolism. With respect to carbohydrate metabolism, insulin increases glucose transport, increases glycogen synthesis, increases pentose shunt activity, increases glucose oxidation and decreases gluconeogenesis.
With respect to lipid metabolism, it increases fatty acid transport and triglyceride synthesis, while decreasing lipolysis. So hyperlipidemia is also a concern with diabetic pts, they will commonly be taking anti-cholesterol medications (lipid lowering drugs) as well.
The nomenclature for insulin is all over the place. There are many insulins and analogs. They are divided into short acting (if in a zinc suspension, it adds a little bit to the duration of action), intermediate acting (may still need to be used more than once a day) and long acting versions (about 36 hours, slow onset of action).
Lantus is the first and only insulin analog that provides 24-hour basal glucose-lowering activity with just one shot. This is a new medication. Although there are no high peaks of insulin, but a constant blood level.
All orally effective, can be used in type 1 individual as supplement to insulin. Their half-lives vary a little. They have high plasma protein binding. There is a serious issue, NSAIDs especially compete for the same binding site that sulfonylurea binds to. If you add an NSAID to a pt taking a sulfonlyurea drug they will displace the drug. The duration of action can range from a ½ to a full day. The choice between the different sulfonylurea drugs is very subtle.
Insulin is the only drug effective for diabetes type 1. The oral hypoglycemic agents are primarily designed for type 2, but some type 2 diabetics do need insulin to get under tight control (the insulin must be injected). If a pt is not controlled by the highest possible sulfonylurea dose, if they were to get into within 10% of their appropriate weight and exercise moderately (walking, swimming…) the requirement of their sulfonylurea dose decreases markedly, some pts can stop taking the drug altogether. So you ask: Why don’t all diabetics lose weight and start exercising? Its like anything else, how do you modify behavior? That discipline is called barostatic medicine.
Metformin is seen most frequently in clinic, it doesn’t release insulin from the pancreatic beta cells, but facilitates the transport of glucose.
- Problems with insulin include hypoglycemia, local or systemic allergic reactions, visual disturbances, and peripheral edema. Hypoglycemia is the most important to moniter, must know the pt’s glucose level before an appt, make sure they are well controlled before beginning.
- Problems with sulfonylureas include hypoglycemia, gastrointestinal disturbances, hematological disturbances, flushing (especially with alcohol ingestion), contraindicated in pts with hepatic or renal insufficiency, and drug interactions.
- Problems with Metformin include lactic acidosis (more likely in pts with renal insufficiency in whom the drug can accumulate), and gastrointestinal problems.
- Problems with Acarbose include abdominal pain, diarrhea and flatulence (uh-oh… only make appointments on windy days, otherwise keep them out of your dental chair. Flatulence in the dental office is not a good practice-builder!)
Polyuria, polydipsia and unexplained weight loss in addition to casual plasma glucose concentrations greater than 200 mg/dL (casual means just a random sample regardless of the time since the last meal)…
OR, if the fasting plasma glucose is greater than 126 mg/dL (fasting is defined as no caloric intake for at least 8 hours)…
OR, if the plasma glucose is greater than 200 mg/dL at 2 hours post caloric intake, during an oral glucose tolerance test.
Recently, the criteria for diagnosing a diabetic state was changed – for fasting plasma glucose levels, the former level that defined diabetes was 140 mg/dL, NOW its 126 mg/dL.
- Non-insulin dependent patient: all dental procedures can be performed, no special precautions are needed unless complications of diabetes are present.
- Insulin-controlled patient: Usually all dental procedures can be performed, morning appointments are usually best. Advise pt to take usual insulin dosage and normal meals on day of dental appointment; confirm when pt comes for appointment. Advise the pt to inform you or your staff if symptoms of insulin reaction occur during the dental visit and have a source of glucose (orange juice, glucola) available and give it to pt if symptoms of insulin reaction occur.
- Extensive surgery needed: consult with physician concerning dietary needs during postoperative period. Consider prophylactic antibiotics for pt with brittle diabetes (the opposite of tightly controlled) or one taking high doses of insulin to prevent postoperative infection.
- Special precautions may be needed for pt with complications of diabetes, renal disease, heart disease, etc.
InsulinCorticosteroids may increase glucose levels. High doses of salicylate analgesics (aspirin et al.) and certain NSAIDs (especially Ibuprofen and Naproxen) increase hypoglycemic action.
Type 1 diabetics are at risk for leukopenia, thrombocytopenia, delayed wound healing,
- increased risk of infection, hypo-hyperglycemic episodes, angioapathy, neuropathy, retinopathy, platelet hyperaggregability, periodontal disease, and gingival bleeding. Beta-blockers may mask sings of hypoglycemia. Alcohol enhances insulin action.
Oral antidiabetic agents (OAAs)In Type 2 diabetics: glucocorticoids may increase glucose, beta-blockers may inhibit
- insulin release, salicylates and some NSAIDs cause serum protein displacement of OAA’s, leading to hypoglycemia, antabuse type reaction with alcohol, metformin and pheformin cause elevated lactoate (lactic acidosis), sulfur-containing OAA’s, weight loss reduces OAA dose needs, and hyperinsulinemia may be present.
Mild stage: hunger, weakness, tachycardia, pallor, sweating, paresthesias
Moderate stage: incoherence, uncooperativeness, belligerence, lack of judgment, poor orientation.
Severe stage: unconsciousness, tonic or clonic movements, hypotension, hypothermia, rapid thready pulse.
The Thiazolidinedione class includes Rosiglitazone (Avandia) and Pioglitazone (Actos). Given the action of metformin and the sulfonylureas, you can combine the agents for useful effects. Combination therapy with insulin and sulfonylurea may be a more appropriate and a suitable option to insulin monotherapy in subjects with non-insulin-dependent diabetes in whom primary or secondary failure of sulfonylurea developed. Approximately 50% of diabetic pts may lose adequate metabolic control using oral agents after 10 years, primarily because of relative insulin deficiency and continuing insulin resistance.
