Abc do diabetes

Abc do diabetes

(Parte 9 de 19)

These drugs are licensed for use with metformin if this alone has failed to control the diabetes, or with a sulphonylurea if metformin is either not tolerated or contraindicated (for example, in renal failure). In the European Union they are not licensed for use alone or in combination with insulin, and should not be given to patients with a history of heart failure, or during pregnancy. They may cause oedema, a minor reduction of haemoglobin, and a small increase of HDL cholesterol. There are very rare reports of liver dysfunction, and liver function should be monitored before, and every two months after, starting treatment, for the following 12 months.

Drugs for management of obesity There is a limited place for the use of medication in assisting with weight reduction in the obese diabetic patient. The use of such drugs is restricted to those whose BMI is 28 or more and who are between the ages of 18 and 65 years; they should only be prescribed for individuals who have lost at least 2·5kg body weight by diet and exercise during the preceding month. Patients should continue to be supported by their advisers and counsellors throughout treatment. Orlistat inhibits fat absorption by inhibition of pancreatic lipase. Weight reduction

Side effects of metformin

• Nausea • Diarrhoea

•Metallic taste

These effects can be minimised by starting with a low dose and taking tablets during meals. The effects generally resolve with time

Thiazolidinediones should be used in patients expected to be insulin resistant, namely those who are overweight and likely to be hyperlipidaemic and hypertensive as well

Useful drug combinations

•Sulphonylurea (or metaglitidine analogue) with metformin •Sulphonylurea (or metaglinide analogue) with thiazolidinedione (if metformin is contraindicated or not tolerated) •Metformin with thiazolidinedione

•Nateglinide with metformin

•Metformin with insulin (for overweight patients)

•Acarbose can be used in association with any of the above

Treatment of Type 2 diabetes mellitus indicating a successful response should be greater than 5% after 12 weeks, in which event prescription may be continued for one year to a limit of two years, otherwise treatment should cease. Unpleasant oily leakage and steatorrhoea can occur.

Sibutramine also acts centrally as a serotonin and noradrenaline reuptake inhibitor and enhances the satiety response. It is used as an adjunct to weight maintenance after weight loss. Full details of its use and contraindications are to be found in the BNF.

Guar gum Guar gum preparations, taken in adequate quantity three times daily before meals, can reduce postprandial blood glucose concentrations. Flatulence is common and often unacceptable. Guarem is the only available preparation. It has a very limited role.

Hypoglycaemia Only sulphonylureas and meglitidine analogues cause hypoglycaemia, but it should not be allowed to occur at all—it almost invariably indicates excessive dosage. Those most at risk are elderly people who may make dosage errors or fail to take their normal meals. Hypoglycaemia in this situation can be fatal. The shorter acting sulphonylureas cause the least hypoglycaemia and are therefore best for older people (see below). Management of hypoglycaemia is described in chapter 8. Blockers may not only exacerbate hypoglycaemia, but also occasionally inhibit the early warning symptoms.

Indications for insulin in Type 2 diabetes Approximately 6% of non-obese and 2% of obese Type 2 diabetic patients need to start insulin each year. Predicting the need for insulin is difficult: those of lean body mass, especially in the presence of islet cell antibodies, are at greatest risk.

Whether to give insulin to Type 2 diabetic patients is one of the most important yet difficult decisions to be made in treating these patients. Failure to give insulin to some patients results in protracted and needless malaise if not actual danger. On the other hand, giving insulin inappropriately can cause needless problems, notably from hypoglycaemia and weight gain.

Indications for giving insulin to Type 2 diabetic patients who are inadequately controlled despite adherence to their recommended diet and oral hypoglycaemic agents are as follows:

•Continuing weight loss (even if this is insidious), and persistent symptoms, or both. Insulin treatment in these patients almost always results in a substantial improvement in health.

•A non-obese patient without symptoms whose weight is stable and who is conscientious with existing medication. Diabetic control will usually improve, and about half of the patients will enjoy an improvement in well-being.

•An obese patient without symptoms whose weight is stable presents an even more difficult problem. The correct management is to ensure that they are taking their medication, together with intensification of diet, but sometimes insulin may be needed simply to improve control of diabetes in order to reduce long-term complications during the following decade or more. A reduction of HbA1C of approximately 2% together with weight gain of around

5-7kg can be expected. Unfortunately improvement in glycaemic control is not always achieved. Patient choice is important here, and some prefer not to take insulin after all explanations have been presented. Reluctant patients can be

Drug interactions

•Alcohol can cause serious hypoglycaemia when used with sulphonureas and lactic acidosis in those taking metformin

•Aspirin, sulphonamides, and monoamine oxidase inhibitors may enhance the hypoglycaemic action of sulphonylureas, but in practice problems are rarely seen

•Selective serotonin reuptake inhibitors used in the treatment of depression may provoke hypoglycaemia

•Serious hyperglycaemia is provoked by corticosteroids, dopexamine (inotropic support agent) and intravenous agonists (salbutamol, terbutaline, ritrodrine)

•Thiazide diuretics (other than minimum dosage, for example, bendrofluazide 2.5mg) can exacerbate hyperglycaemia

•The immunosuppressive drug ciclosporin can also exacerbate hyperglycaemia

•Protease inhibitors used in the treatment of patients with HIV can cause a syndrome of lipodystrophy, hyperlipidaemia, and insulin resistance leading to severe exacerbation of hyperglycaemia or even causing diabetes •Clozapine may provoke hyperglycaemia

• blockers may exacerbate hyperglycaemia or hypoglycaemia depending on dose, concomitant medication, nutritional state, severity of illness, and the patient’s age

•Other less common drug interactions are described in the BNF

Indications for insulin in Type 2 diabetes

•Insulin is usually contraindicated in overweight patients whose weight is increasing—giving insulin will make this worse

•Patients who continue to lose weight usually need insulin •Achievement of tight control in order to prevent complications is obviously more appropiate in younger than in older patients, so the patient’s age needs to be considered in deciding whether or not to start giving insulin

•Many older patients, however, benefit greatly from insulin treatment, with an improvement of well-being, and insulin should not be withheld on grounds of age alone

Severe symptoms

Insulin therapy

Poor control Reinforce diet

Poor control

Poor control Add metformin

Poor control Add sulphonylurea

Obese

Low calorie diet

Non-obese Diet

Poor control

WeightlossNo weight loss

Weightloss WeightgainNo weightlossTrial of insulin

Trial of insulin

(Parte 9 de 19)

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