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Pharmacotherapeutic group: serum lipid reducing agents/cholesterol and triglyceride reducers/HMG-CoA reductase inhibitors, ATC-Code: C10AA03Mechanism of action:Pravastatin is a competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, the enzyme catalysing the early rate-limiting step in cholesterol biosynthesis, and produces its lipid-lowering effect in two ways. Firstly, with the reversible and specific competitive inhibition of HMG-CoA reductase, it effects modest reduction in the synthesis of intracellular cholesterol. This results in an increase in the number of LDL-receptors on cell surfaces and enhanced receptor-mediated catabolism and clearance of circulating LDL-C.Secondly, pravastatin inhibits LDL production by inhibiting the hepatic synthesis of VLDL-cholesterol, the LDL-C precursor.In both healthy subjects and patients with hypercholesterolaemia, pravastatin sodium lowers the following lipid values: total cholesterol, LDL-C, apolipoprotein B, VLDL-cholesterol and triglycerides; while HDL-cholesterol and apolipoprotein A are elevated.Clinical efficacy:
Primary prevention
WOSCOPS was a randomised, double-blind, placebo-controlled trial among 6,595 male patients aged from 45 to 64 years with moderate to severe hypercholesterolaemia (LDL-C: 155-232 mg/dl [4.0-6.0 mmol/l]) and with no history of MI, treated for an average duration of 4.8 years with either a 40 mg daily dose of pravastatin or placebo as an adjunct to diet. In pravastatin-treated patients, results showed:- a decrease in the risk of mortality from coronary disease and of non-lethal MI (relative risk reduction [RRR] was 31%; p = 0.0001 with an absolute risk of 7.9% in the placebo group, and 5.5% in pravastatin treated patients); the effects on these cumulative cardiovascular events rates being evident as early as 6 months of treatment;- a decrease in the total number of deaths from a cardiovascular event (RRR 32%; p = 0.03);- when risk factors were taken into account, a RRR of 24% (p = 0.039) in total mortality was also observed among patients treated with pravastatin;- a decrease in the relative risk for undergoing myocardial revascularisation procedures (coronary artery bypass graft surgery or coronary angioplasty) by 37% (p = 0.009) and coronary angiography by 31% (p = 0.007).The benefit of the treatment on the criteria indicated above is not known in patients over the age of 65 years, who could not be included in the study.In the absence of data in patients with hypercholesterolaemia associated with a triglyceride level of more than 6 mmol/l (5.3 g/l) after a diet for 8 weeks, in this study, the benefit of pravastatin treatment has not been established in this type of patient.
Secondary prevention
The LIPID study was a multi-center, randomised, double-blind, placebo-controlled study comparing the effects of pravastatin (40 mg OD) with placebo in 9014 patients aged 31 to 75 years for an average duration of 5.6 years with normal to elevated serum cholesterol levels (baseline total cholesterol = 155 to 271 mg/dl [4.0-7.0 mmol/l], mean total cholesterol = 219 mg/dl [5.66 mmol/l]) and with variable triglyceride levels of up to 443 mg/dl [5.0 mmol/l] and with a history of MI or unstable angina pectoris in the preceding 3 to 36 months. Treatment with pravastatin significantly reduced the relative risk of coronary heart disease (CHD) death by 24% (p = 0.0004, with an absolute risk of 6.4% in the placebo group, and 5.3% in pravastatin treated patients), the relative risk of coronary events (either CHD death or nonfatal MI) by 24% (p < 0.0001) and the relative risk of fatal or nonfatal MI by 29% (p < 0.0001). In pravastatin-treated patients, results showed:- a reduction in the relative risk of total mortality by 23% (p < 0.0001) and cardiovascular mortality by 25% (p < 0.0001);- a reduction in the relative risk of undergoing myocardial revascularisation procedures (coronary artery bypass grafting or percutaneous transluminal coronary angioplasty) by 20% (p < 0.0001);- a reduction in the relative risk of stroke by 19% (p = 0.048).The CARE study was a randomised, double-blind, placebo-controlled study comparing the effects of pravastatin (40 mg OD) on CHD death and nonfatal MI for an average of 4.9 years in 4,159 patients aged 21 to 75 years, with normal total cholesterol levels (baseline mean total cholesterol < 240 mg/dl), who had experienced a MI in the preceding 3 to 20 months. Treatment with pravastatin significantly reduced:- the rate of a recurrent coronary event (either coronary heart disease death or nonfatal MI) by 24% (p = 0.003, placebo 13.3%, pravastatin 10.4%);- the relative risk of undergoing revascularisation procedures (coronary artery bypass grafting or percutaneous transluminal coronary angioplasty) by 27% (p < 0.001).The relative risk of stroke was also reduced by 32% (p = 0.032), and stroke or transient ischaemic attack (TIA) combined by 27% (p = 0.02).The benefit of the treatment on the above criteria is not known in patients over the age of 75 years, who could not be included in the CARE and LIPID studies.In the absence of data in patients with hypercholesterolaemia associated with a triglyceride level of more than 4 mmol/l (3.5 g/l) or more than 5 mmol/l (4.45 g/l) after following a diet for 4 or 8 weeks, in the CARE and LIPID studies, respectively, the benefit of treatment with pravastatin has not been established in this type of patient.In the CARE and LIPID studies, about 80% of patients had received acetyl-salicylic acid (ASA) as part of their regimen.
Heart and kidney transplantation
The efficacy of pravastatin in patients receiving an immunosuppressant treatment following:- Heart transplant was assessed in one prospective, randomised, controlled study (n = 97). Patients were treated concurrently with either pravastatin (20 - 40 mg) or not, and a standard immunosuppressive regimen of ciclosporin, prednisone and azathioprine. Treatment with pravastatin significantly reduced the rate of cardiac rejection with haemodynamic compromise at one year, improved one-year survival (p = 0.025), and lowered the risk of coronary vasculopathy in the transplant as determined by angiography and autopsy (p = 0.049).- Renal transplant was assessed in one prospective not controlled, not randomised study (n = 48) of 4 months duration. Patients were treated concurrently with either pravastatin (20 mg) or not, and a standard immunosuppressive regimen of ciclosporin, and prednisone. In patients following kidney transplantation, pravastatin significantly reduced both the incidence of multiple rejection episodes and the incidence of biopsy-proved acute rejection episodes, and the use of pulse injections of both prednisolone and Muromonab-CD3.
Children and adolescents (8-18 years of age):
A double-blind placebo-controlled study in 214 paediatric patients with heterozygous familial hypercholesterolaemia was conducted over 2 years. Children (8-13 years) were randomised to placebo (n = 63) or 20 mg of pravastatin daily (n = 65) and the adolescents (aged 14-18 years) were randomised to placebo (n = 45) or 40 mg of pravastatin daily (n = 41).Inclusion in this study required one parent with either a clinical or molecular diagnosis of familial hypercholesterolaemia. The mean baseline LDL-C value was 239 mg/dl (6.2 mmol/l) and 237 mg/dl (6.1 mmol/l) in the pravastatin (range 151-405 mg/dl [3.9-10.5 mmol/l]) and placebo (range 154-375 mg/dl [4.0-9.7 mmol/l]). There was a significant mean percent reduction in LDL-C of -22.9% and also in total cholesterol (-17.2%) from the pooled data analysis in both children and adolescents, similar to demonstrated efficacy in adults on 20 mg of pravastatin. The effects of pravastatin treatment in the two age groups was similar. The mean achieved LDL-C was 186 mg/dl (4.8 mmol/l) (range: 67-363 mg/dl [1.7-9.4 mmol/l]) in the pravastatin group compared to 236 mg/dl (6.1 mmol/l) (range: 105-438 mg/dl [2.7-11.3 mmol/l]) in the placebo group. In subjects receiving pravastatin, there were no differences seen in any of the monitored endocrine parameters [ACTH, cortisol, DHEAS, FSH, LH, TSH, estradiol (girls) or testosterone (boys)] relative to placebo. There were no developmental differences, testicular volume changes or Tanner score differences observed relative to placebo. The power of this study to detect a difference between the two groups of treatment was low.The long-term efficacy of pravastatin therapy in childhood to reduce morbidity and mortality in adulthood has not been established.
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