Prescribing for Diabetes

By Silver, Lisa

Prescribing for diabetes can be complicated, but recent changes in generic pricing mean that GPs now have a range of low-cost options. Dr Lisa Silver reports

More than 1.3 million people have diabetes in the UK. About 85 per cent of them have type 2 diabetes, representing a significant, increasing workload in primary care.

Today’s diabetic patients are treated with a range of medicines to address the long-term complications of retinopathy, nephropathy, neuropathy, CHD, stroke and peripheral vascular disease. The problem of obesity is also increasing.

Controlling blood glucose used to be the sole mantra in the treatment of type 2 diabetes. Now we must also ensure tight control of BP, lipids and diet, to prevent premature morbidity and mortality.

The UK Prospective Diabetes Study (UKPDS), a 20-year study that finished in 1997, is one of the main pieces of research driving diabetic care, together with NICE guidance on the subject.

The course of diabetes is predictable. Initially, patients are controlled with various combinations of drugs, plus lifestyle and dietary management. Insulin is introduced when these measures fail. Diabetic patients may need help to accept the fact that they are likely to be taking a large number of tablets for their condition.

The mainstay of current drug treatment is metformin and the sulphonylureas, particularly short-acting agents such as gliclazide, glimepiride and glipizide.

When there is intolerance to these two agents, or they prove ineffective, this combination is followed by glitazones, such as rosiglitazone or pioglitazone.

For some patients, the insulin secretagogues nateglinide and repaglinide may be required. If there is intolerance to all of these, there may be a place for acarbose, but its gastrointestinal side-effects make it rather user-unfriendly.

Under the new pharmacy contract, the reimbursement prices for generic medicines are being reduced from 800 million to 500 million. Many generic prices have seen massive reductions. Prices are being altered every three months and for diabetes, generics are now very low cost.

Practices can also earn up to 99 QOF points for diabetes. There is currently no national screening programme for the disease. The best approach would be primary prevention, with a programme of education starting at school age.

Intensive control

The UKPDS trial demonstrated that intensive blood glucose control with sulphonylureas or insulin reduced the risk of diabetes-related microvascular end-organ damage, such as retinopathy and renal failure, by 35 per cent, and the nearer the HbA1c was to <6.0 per cent, the better.

Metformin is the first-line diabetic drug, particularly in the obese. It is contraindicated in patients with renal impairment, when the alternative is a sulphonylurea. There is a greater risk of hypoglycaemia with this group, particularly with glibenclamide. When individual therapy fails to control glucose, a combination of metformin and a sulphonylurea is possible.

The glitazones, such as rosiglitazone and pioglitazone, can be used with metformin or a sulphonylurea, but not with both, or with insulin. They are a considerably more expensive option in the range of treatments available for diabetic patients.

The rapidly acting insulin secretagogues nateglinide and repaglinide are useful if a patient has a disorganised day and eats irregularly. Both of these drugs are taken before meals and can be used in combination with metformin.

The chief side-effect of acarbose is excess flatus, which makes it a less sociable medicine to take. But it can be used when other oral preparations have proved unacceptable or ineffective.

The challenge with diabetic patients is compliance. Feeling well and yet having to take many tablets each month is not easy for anybody. Metformin is a large tablet that smells unpleasant, so it is not surprising that patients may fail to take it.

Another factor is that the information provided with medicines is driven by regulations, so the patient only receives the bad news (that is, side-effects and warnings), but nothing about benefits.

Slow-release products

GPs need to think not only about the cost of the drugs, but also about patients’ well-being. There is a place for long-acting and slow-release products, as well as combination therapies. If they are more palatable, easier to swallow and taken once a day, we should be prescribing them. That way, patients are more likely to benefit from the medicine, rather than hoard it in their bathroom cabinets.

It has been claimed that about 50 per cent of medications are wasted, so thought should be given to helping patients take unpalatable medicines. The alternative is to risk expensive inpatient care for diabetic complications. This issue may come under the practice-based commissioning spotlight. GPs could ask their diabetes patients which medicine they prefer to take – after all, patient choice is the key political imperative these days.

Dr Silver is a GP in Oxfordshire

Copyright Haymarket Business Publications Ltd. Sep 2005