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The Pharmaceutical Journal Vol 265 No 7114 September 16, 2000
Pharmacy Practice Research
Papers presented at the British Pharmaceutical Conference, Birmingham, September 10 to 13, 2000 pR13

Switch of patients from simvastatin or pravastatin to fluvastatin in one general medical practice

By Jane M. Thomas* and Roger Walker

Introduction The 1994 Audit Commission report recognised that prescribing costs may need to increase in certain therapeutic areas to improve the quality of patient care.1 The management of cardiovascular disease and the use of statins is one such area. Given the escalating costs associated with the use of statins,2 it is inevitable that practices may look to switch treatment to other, less expensive drugs in the same therapeutic group. Fluvastatin has been identified3 as a cost-effective statin, although there is debate over its relative potency.4 The following study was undertaken in one general medical practice where the practice pharmacist was invited to set up a lipid clinic and switch patients receiving a statin to fluvastatin.

Method Patients receiving repeat prescriptions for either simvastatin or pravastatin at daily doses of 10mg or 20mg were identified. Blood samples were drawn for determination of total cholesterol, low density lipoprotein (LDL), high density lipoprotein (HDL) and triglycerides (TG). All patients were subsequently changed to fluvastatin 40mg and asked to return to the clinic after three months to have their lipid levels remeasured. If they failed to return, baseline values were used in subsequent calculations.
Results were analysed by SPSS version 9.0 using the Wilcoxon signed rank test and presented as mean ± standard deviation together with 95 per cent confidence intervals (CI). Twelve months after the start of the study patients were followed up to assess statin usage.

Focal points

  • Fluvastatin may be considered a cost effective statin
  • Patients receiving simvastatin or pravastatin were switched to fluvastatin
  • Total and LDL cholesterol increased in patients treated with fluvastatin and there was a marked increase in side effects
  • Switching patients to fluvastatin did not confer benefit and had disadvantages

Results Fifty-three patients were eligible for the study, of whom 42 attended the surgery to have their lipid lowering therapy switched to fluvastatin. Thirty-six (86 per cent) patients returned to the clinic after three months for reassessment. Of the six who failed to return, five had stopped taking fluvastatin because of side effects and had changed back to their original statin and one refused to attend and stopped collecting repeat prescriptions. LDL levels could not be calculated for one patient with high TG levels.
When lipid levels were measured after three months on fluvastatin 40mg, there was an increase in total and LDL cholesterol from 5.29±0.97 (CI 4.90-5.50) to 5.77±1.01 (CI 5.40-6.20) mmol/L (P< 0.001, n=42) and 3.17 ±0.87 (CI 2.85-3.37) to 3.60±0.90 (CI 3.31-3.85) mmol/L (P< 0.001, n=41), respectively. A significant (P=0.020, n=41) drop in the HDL:LDL ratio of 0.06±0.16 (CI -0.10-0.00) was also observed.
Twelve months after the start of the study 23 (55 per cent) patients remained on fluvastatin while 19 had stopped treatment. In 11 of these 19 patients, cholesterol levels had increased after three months on fluvastatin 40mg and they had subsequently been changed back to their original statin. Six patients had stopped taking fluvastatin because of side-effects (one muscle pains, two indigestion and muscle pains, two upset stomach, one itching) and two patients had stopped collecting their repeat prescriptions.

Discussion Fluvastatin at the dose studied failed to maintain or reduce cholesterol levels in patients who had previously received simvastatin or pravastatin. These results are consistent with those of a previous report5 in which total and/or LDL cholesterol increased in 94 per cent of patients changed from simvastatin to fluvastatin. In the present study, response varied markedly between patients and there was poor tolerability of side-effects with an associated high discontinuation rate. These findings indicate that at the practice level a switch to fluvastatin for cost reasons alone cannot be justified.

*Caerphilly local health group, Ystrad Mynach, Gwent health authority, Pontypool; Welsh school of pharmacy, Cardiff university

References

1. Audit Commission. A prescription for improvement. Towards more rational prescribing in general practice. London: Stationery Office, 1994.
2. Bradshaw N, Walker R. Prescription of statins: cost implications of evidence-based treatment applied to a health authority population. J Clin Pharm Ther 1997;22:379-89.
3. Morris S, Godber E. Choice of cost-effectiveness measure in the economic evaluation of cholesterol-modifying pharmacotherapy. An illustrative example focusing on the primary prevention of coronary heart disease in Canada. Pharmacoeconomics 1999;16:193-205.
4. Schulte K, Stefan B. Efficacy and tolerability of fluvastatin and simvastatin in hypercholesterolaemic patients. Clin Drug Invest 1996;12:119-26.
5. Thomas M, Mann J. Research Letter: increased thrombotic vascular events after change of statin. Lancet 1998;352: 1830-1.