Viewpoint: The argument for switching statins

Switching from low-dose branded statins to simvastatin 40mg can bring benefits, say Dr James Moon and Dr Richard Bogle

Switching patients from expensive low-dose branded statins to simvastatin 40mg would appear to bring enormous financial savings without loss of clinical effectiveness, but is the effort involved worth it? There has been much debate on the issue due to the potential effects on the NHS drug budget.

At the end of 2005 there were more than 1.1 million people taking atorvastatin 10mg/20mg in England, at a cost of £18.03– £24.64 per person each month.

Simvastatin 40mg costs £4.17 per month. Switching these people would save £236 million per year — a substantial proportion of total NHS debt. On average, every patient switched saves £1,000 over five years, or enough to treat four currently untreated individuals.

One argument is that we should not bother switching when atorvastatin will come off patent soon. However, atorvastatin does not actually come off patent for another five years, that is in November 2011.

Differing potencies

Statins all work by blocking the same enzyme, but differ in potency. Higher doses of less potent statins can equal or better the efficacy of lower doses of more potent ones, which is why switching from atorvastatin 10mg/20mg to simvastatin 40mg has been proposed.

Where superior lipid lowering is required, a high-dose statin strategy — simvastatin 80mg (as 2 x 40mg tablets), atorvastatin 40mg or rosuvastatin would be better than atorvastatin 20mg. There is equivalent evidence for atorvastatin 10mg (CARDS, ASCOT-LLA) and simvastatin 40mg (HPS, 4S) but atorvastatin 20mg has no clinical trial endpoint data supporting its use.

Simvastatin 40mg has been shown in clinical trials to be equivalent or superior to all doses of atorvastatin in improving HDL, therefore the switch might benefit patients.

Serious side-effects occur rarely with low-dose statins; however, there is no evidence that at equivalent lipid-lowering doses there is any difference in side-effect profile or compliance between atorvastatin and simvastatin.

Atorvastatin and simvastatin have broadly the same metabolic pathways and drug interactions, so it is reasonable to switch with no additional monitoring, although an early INR check is recommended for patients on warfarin.

For patients on powerful CYP3A4-inhibiting medications (such as cyclosporin), pravastatin 40mg is a good generic alternative because it is not metabolised this way.

Risk of renal failure

Atorvastatin and simvastatin have significant renal excretion; renal failure makes the drugs more effective, so it is best to start cautiously with simvastatin 10mg and increase the dose gradually if needed.

In advanced renal failure (GFR<30ml/min), atorvastatin 20mg should be avoided because one large study showed an excess of haemorrhagic stroke in the atorvastatin 20mg patients.

Since the publication of the HPS and CARDS trials there is good equivalent evidence for simvastatin 40mg and atorvastatin 10mg in patients with diabetes.

Simvastatin 40mg can treat to target and is no better or worse than atorvastatin 10mg/20mg. There are no trials evaluating the lowering of cholesterol to a particular target in primary prevention, making JBS2 targets for these individuals non-evidence based. The current targets, combined with effective multifactorial risk reduction including exercise, diet and good diabetes control as well as drugs such as aspirin and antihypertensive treatment, seem to be optimal.

When starting a new patient on statins most side-effects are dose-related. We therefore suggest reducing the dose of simvastatin or using pravastatin up to 40mg.

Simvastatin off patent

Simvastatin is cheap. It used to cost the same as low-dose atorvastatin, but it came off patent in 2003. Since then its price has fallen by up to 20 times. It is literally as easy to make as beer — you remove the supernatant from Aspergillus fermentation and perform one chemical step.

At first glance, it would appear that switching everyone is ridiculous. But so is the current situation in England. In some PCTs (for example, Cotswold and Vale), atorvastatin 10mg/ 20mg is prescribed to 8 per cent of statin users and the average statin scrip costs £8.17, while other PCTs have up to 61 per cent atorvastatin 10mg/20mg usage costing up to £28.89 per scrip. Prescriber choice rather than evidence-based medicine is the only explanation.

Savings in London

UCL Hospital NHS Trust stopped stocking atorvastatin 10mg/20mg and uses simvastatin 40mg instead, reducing dispensing atorvastatin from 200 to one a month — a 99.5 per cent reduction. The one recent patient kept on low-dose atorvastatin was being uptitrated for familial hypercholesterolaemia.

A PCT-wide switching programme in Hammersmith and Fulham successfully switched 1,300 patients. When Hammer-smith and Fulham PCT switched, the entire cost of switching was recouped within 30 days. A single switch in a clinic (saving £1,000) makes the whole clinic cost-effective.

Making the switch

Careful handling of the switch is vital. Hammersmith and Fulham PCT wrote to patients informing them that a review of medicines had been undertaken and that their scrips would be swapped — 85 per cent of patients were keen to switch and supportive of attempts to use medicines more cost-effectively.

Some doctors might say that switching reduces their clinical freedom, but it produces savings to meet unmet need and to increase freedom in other arenas. For example, it is estimated that NICE guidelines mean up to one adult in four may need statin treatment plus new NICE AF guidelines need to be paid for.

Switching is straightforward and software is available to identify suitable patients. Working with your PCT pharmacist can also help. The work involved is worth it for the saving.

Statin-switching standard operating procedures have been developed for SHA, PCT, tertiary care and GP level. Contact us for copies by email at and

Dr Moon is specialist registrar, department of cardiology, Heart Hospital, UCL Hospitals NHS Foundation Trust, London, and Dr Bogle is acting consultant in cardiology and clinical pharmacology, Imperial College London

key points

Statins represent the largest drug cost to the NHS.

Every patient switched saves the NHS £1,000 over five years.

Statins all work by blocking the same enzyme, but differ in potency.

There is equivalent evidence from clinical trials for atorvastatin 10mg (CARDS, ASCOT-LLA) and simvastatin 40mg (HPS, 4S).

In advanced renal failure (GFR<30ml/min), atorvastatin 20mg should be avoided.

Switching statins is straightforward.


Colhoun H M, Betteridge D J, Durrington P N,et al. Rapid emergence of effect of atorvastatin on cardiovascular outcomes in the Collaborative Atorvastatin Diabetes Study (CARDS). Diabetologia 2005; 48: 2,482–5

Sever P S, Dahlof B, Poulter N R, et al. ASCOT investigators. Prevention of coronary and stroke events with atorvastatin in hypertensive patients who have average or lower-than-average cholesterol concentrations, in the Anglo-Scandinavian Cardiac Outcomes Trial—Lipid Lowering Arm (ASCOT-LLA): a multicentre randomised controlled trial. Lancet 2003; 361: 1,149–58

Heart Protection Study Collaborative Group. MRC/BHF Heart Protection Study of cholesterol lowering with simvastatin in 20,536 high-risk individuals: a randomised placebo-controlled trial. Lancet 2002; 360: 7–22

Randomised trial of cholesterol lowering in 4444 patients with CHD: the Scandinavian Simvastatin Survival Study (4S). Lancet 1994; 344: 1,383–9

Jones P H, Davidson M H, Stein E A, et al; STELLAR Study Group. Comparison of the efficacy and safety of rosuvastatin versus atorvastatin, simvastatin, and pravastatin across doses (STELLAR* Trial) Am J Cardiol 2003; 92: 152–60

Jaber B L, Madias N E. Atorvastatin in patients with type-2 diabetes mellitus undergoing dialysis. N Engl J Med 2005; 353(17): 1,858–60

PCT-wide switching programme in Hammersmith and Fulham successfully switched 1,300 patients.

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