RISTOMIB 20/10 mg

Indications

• Adjunct to dietary measures in primary hypercholesterolaemia
• Adjunct to dietary measures and statin treatment in homozygous familial hypercholesterolaemia
• Adjunct to dietary measures in homozygous sitosterolaemia

Dosage

Children: Refer to the BNF for Children for appropriate dosing information, as the

Adults: The typical adult dosage of ezetimibe is 10 mg once daily.

Mechanism of action

Ezetimibe mediates its cholesterol-lowering effects by selectively inhibiting the absorption of cholesterol and phytosterols in the small intestine. It primarily targets the Niemann-Pick C1-Like 1 (NPC1L1) protein, which is vital for the internalization of free cholesterol into enterocytes. By blocking this protein at the jejunal brush border, ezetimibe reduces intestinal cholesterol uptake, consequently lowering hepatic cholesterol levels and enhancing cholesterol clearance from the blood.

Pharmacodynamics

Ezetimibe effectively reduces levels of total cholesterol, low-density lipoprotein cholesterol (LDL-C), apoprotein B (Apo B), non-high-density lipoprotein cholesterol (non-HDL-C), and triglycerides while increasing high-density lipoprotein cholesterol (HDL-C) in patients with hyperlipidemia. Its lipid-lowering effects are significantly enhanced when used in combination with statins or fenofibrate, resulting in substantial reductions in LDL levels and modest increases in HDL-C.

Pharmacokinetics

Ezetimibe is absorbed in the gastrointestinal tract and undergoes extensive first-pass metabolism to its active form. The elimination half-life is approximately 22 hours, and it is primarily excreted in the bile. The pharmacokinetics may be affected by hepatic impairment, and its use is not recommended in patients with significant liver disease. Ezetimibe does not require exocrine pancreatic function for its activity.

Contra-indications

• Gall bladder disease
• Hypoalbuminaemia
• Nephrotic syndrome
• Severe hepatic impairment

Adverse effects

• Common or very common: Asthenia, gastrointestinal discomfort, decreased appetite, diarrhea, dizziness, headache, muscle complaints
• Uncommon: Acute kidney injury, alopecia, cholestasis, erectile dysfunction, nausea, photosensitivity reaction
• Rare or very rare: Cholelithiasis, depression, insomnia, interstitial lung disease, pancreatitis, pancytopenia, peripheral neuropathy, rhabdomyolysis

Interactions

• Ciclosporin: Increases exposure to ciclosporin when co-administered
• Bulevirtide: Unknown interaction affecting efficacy

Precautions

• Use with caution in patients with moderate to severe hepatic impairment
• Monitor for signs of muscle pain or weakness, especially if used concurrently with statins

Pregnancy

Manufacturer advises use only if potential benefit outweighs risk; no information available.

Breast-feeding

Manufacturer advises avoiding use; no information available.

Storage

Store at room temperature, away from moisture and heat.

Formulations

• Ezetimibe 10 mg tablets

Mechanism of action

Rosuvastatin acts as a competitive inhibitor of HMG-CoA reductase, the enzyme responsible for converting HMG-CoA to mevalonate, a crucial step in cholesterol biosynthesis. By inhibiting this enzyme, rosuvastatin decreases hepatic cholesterol levels, which in turn upregulates the expression of hepatic LDL receptors, enhancing the uptake of LDL cholesterol from the circulation. Additionally, it reduces the hepatic synthesis of very low-density lipoprotein (VLDL). Beyond its lipid-lowering effects, rosuvastatin exhibits pleiotropic effects, improving endothelial function, stabilizing atherosclerotic plaques, reducing oxidative stress and inflammation, and inhibiting thrombogenic responses.

Pharmacodynamics

Rosuvastatin effectively lowers total cholesterol, LDL-C, apolipoprotein B (apoB), and triglycerides while raising HDL-C levels. High levels of LDL-C and triglycerides, along with low HDL-C, are associated with an increased risk of atherosclerosis and cardiovascular disease (CVD). By improving the total cholesterol to HDL-C ratio, rosuvastatin reduces the risk of cardiovascular morbidity and mortality. Statins, including rosuvastatin, are considered cost-effective in managing CVD due to their significant impact on reducing LDL levels and overall cardiovascular risk.

Pharmacokinetics

Rosuvastatin is rapidly absorbed after oral administration, with peak plasma concentrations typically occurring within 3 to 5 hours. It has a bioavailability of approximately 20%, and its absorption is not significantly affected by food. The drug is primarily metabolized in the liver, and about 90% of the administered dose is excreted in the faeces, with the remainder eliminated via urine. The half-life of rosuvastatin is approximately 19 hours, allowing for once-daily dosing. Renal impairment may

Contra-indications

• Active liver disease
• Pregnancy
• Known hypersensitivity to rosuvastatin or any excipients

Adverse effects

• Muscle weakness
• Myopathy
• Rhabdomyolysis
• Abnormal liver function tests
• Gastrointestinal disturbances
• Headache
• Dizziness
• Allergic reactions including angioedema

Interactions

• Ciclosporin increases exposure
• Darolutamide increases exposure
• Letermovir increases exposure
• Tedizolid increases exposure
• Voxilaprevir with sofosbuvir and velpatasvir markedly increases exposure
• Dronedarone moderately increases exposure
• Leflunomide moderately increases exposure
• Roxadustat moderately increases exposure
• Apalutamide decreases exposure
• Eslicarbazepine decreases exposure

Precautions

• Monitor liver function tests prior to and during treatment
• Use with caution in patients with a history of muscle disorders
• Caution in patients with renal impairment
• Consider alternative therapy for patients with a history of statin intolerance

Pregnancy

Manufacturer advises against use during pregnancy due to potential harm to the fetus.

Breast-feeding

Manufacturer advises avoiding use during breastfeeding, as small amounts may be present in breast milk.

Storage

Store in a cool, dry place below 30°C. Protect from light.

Formulations

• Tablets: 5 mg, 10 mg, 20 mg, 40 mg
• Oral suspension
• Oral solution

Mechanism of action

Ezetimibe mediates its blood cholesterol-lowering effect via selectively inhibiting the absorption of cholesterol and phytosterol by the small intestine without altering the absorption of fat-soluble vitamins and nutrients. The primary target of ezetimibe is the cholesterol transport protein Niemann-Pick C1-Like 1 (NPC1L1) protein. NPC1L1 is expressed on enterocytes/gut lumen (apical) as well as the hepatobiliary (canalicular) interface and plays a role in facilitating internalization of free cholesterol into the enterocyte in conjunction with the adaptor protein 2 (AP2) complex and clathrin. Once cholesterol in the gut lumen or bile is incorporated into the cell membrane of enterocytes, it binds to the sterol-sensing domain of NPC1L1 and forms a NPC1L1/cholesterol complex. The complex is then internalized or endocytosed by joining to AP2 clathrin, forming a vesicle complex that is translocated for storage in the endocytic recycling compartment. Ezetimibe does not require exocrine pancreatic function for its pharmacological activity; rather, it localizes and appears to act at the brush border of the small intestine. Ezetimibe selectively blocks the NPC1L1 protein in the jejunal brush border, reducing the uptake of intestinal lumen micelles into the enterocyte. Overall, ezetimibe causes a decrease in the delivery of intestinal cholesterol to the liver and reduction of hepatic cholesterol stores and an increase in clearance of cholesterol from the blood. While the full mechanism of action of ezetimibe in reducing the entry of cholesterol into both enterocytes and hepatocytes is not fully understood, one study proposed that ezetimibe prevents the NPC1L1/sterol complex from interacting with AP2 in clathrin coated vesicles and induces a conformational change in NPC1L1, rendering it incapable of binding to sterols. Another study suggested that ezetimibe disrupts the function of other protein complexes involved in regulating cholesterol uptake, including the CAV1–annexin 2 heterocomplex. Niemann-Pick C1-like 1 (NPC1L1) is a polytopic transmembrane protein that plays a critical role in cholesterol absorption. Ezetimibe, a hypocholesterolemic drug, has been reported to bind NPC1L1 and block cholesterol absorption. However, the molecular mechanism of NPC1L1-mediated cholesterol uptake and how ezetimibe inhibits this process are poorly defined. Here we find that cholesterol specifically promotes the internalization of NPC1L1 and that this process requires microfilaments and the clathrin/AP2 complex. Blocking NPC1L1 endocytosis dramatically decreases cholesterol internalization, indicating that NPC1L1 mediates cholesterol uptake via its vesicular endocytosis. Ezetimibe prevents NPC1L1 from incorporating into clathrin-coated vesicles and thus inhibits cholesterol uptake. ... Niemann-Pick C1-like protein (NPC1L1) mediates the absorption of dietary cholesterol in the proximal region of the intestine, a process that is blocked by cholesterol absorption inhibitors (CAIs), including ezetimibe. Using a proteomic approach, /it is/ demonstrated that NPC1L1 is the protein to which ezetimibe and its analogs bind. Next, ... the site of interaction of ezetimibe analogs /was determined/ with NPC1L1 by exploiting the different binding affinities of mouse and dog NPC1L1 for the radioligand analog of ezetimibe, [(3)H]AS. Chimeric and mutational studies indicate that high-affinity binding of [(3)H]AS to dog NPC1L1 depends on molecular determinants present in a 61-aa region of a large extracellular domain (loop C), where Phe-532 and Met-543 appear to be key contributors. These data suggest that the [(3)H]AS-binding site resides in the intestinal lumen and are consistent with preclinical data demonstrating in vivo efficacy of a minimally bioavailable CAI. Furthermore, these determinants of [(3)H]AS binding lie immediately adjacent to a hotspot of human NPC1L1 polymorphisms correlated with hypoabsorption of cholesterol. These observations, taken together wit

Pharmacodynamics

Ezetimibe was shown to reduce the levels of total cholesterol (total-C), low-density lipoprotein cholesterol (LDL-C), apoprotein B (Apo B), non-high-density lipoprotein cholesterol (non-HDL-C), and triglycerides (TG), and increase high-density lipoprotein cholesterol (HDL-C) in patients with hyperlipidemia. This therapeutic effect was more profound when ezetimibe was co-administered with a statin or fenofibrate compared to either treatment alone. In clinical trials involving patients with homozygous and heterozygous familial hypercholesterolemia and in those with sitosterolemia, a recommended therapeutic dose of ezetimibe was effective in reducing the LDL levels by 15-20% while increasing HDL-C by 2.5-5%. The effects of increased exposure to ezetimibe secondary to moderate-severe hepatic impairment have not been assessed - patients meeting these criteria should avoid the use of ezetimibe. Post-marketing reports indicate the potential for myopathy and rhabdomyolysis in patients taking ezetimibe, and this risk appears to be exacerbated in patients concurrently receiving, or having recently received, statin therapy.

Mechanism of action

Rosuvastatin is a statin medication and a competitive inhibitor of the enzyme HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase, which catalyzes the conversion of HMG-CoA to mevalonate, an early rate-limiting step in cholesterol biosynthesis. Rosuvastatin acts primarily in the liver, where decreased hepatic cholesterol concentrations stimulate the upregulation of hepatic low density lipoprotein (LDL) receptors which increases hepatic uptake of LDL. Rosuvastatin also inhibits hepatic synthesis of very low density lipoprotein (VLDL). The overall effect is a decrease in plasma LDL and VLDL. In vitro and in vivo animal studies also demonstrate that rosuvastatin exerts vasculoprotective effects independent of its lipid-lowering properties, also known as the pleiotropic effects of statins. This includes improvement in endothelial function, enhanced stability of atherosclerotic plaques, reduced oxidative stress and inflammation, and inhibition of the thrombogenic response. Statins have also been found to bind allosterically to β2 integrin function-associated antigen-1 (LFA-1), which plays an important role in leukocyte trafficking and in T cell activation. Rosuvastatin exerts an anti-inflammatory effect on rat mesenteric microvascular endothelium by attenuating leukocyte rolling, adherence and transmigration. The drug also modulates nitric oxide synthase (NOS) expression and reduces ischemic-reperfusion injuries in rat hearts. Rosuvastatin increases the bioavailability of nitric oxide by upregulating NOS and by increasing the stability of NOS through post-transcriptional polyadenylation. It is unclear as to how rosuvastatin brings about these effects though they may be due to decreased concentrations of mevalonic acid. Crestor is a selective and competitive inhibitor of HMG-CoA reductase, the rate-limiting enzyme that converts 3-hydroxy-3-methylglutaryl coenzyme A to mevalonate, a precursor of cholesterol. In vivo studies in animals, and in vitro studies in cultured animal and human cells have shown rosuvastatin to have a high uptake into, and selectivity for, action in the liver, the target organ for cholesterol lowering. In in vivo and in vitro studies, rosuvastatin produces its lipid-modifying effects in two ways. First, it increases the number of hepatic LDL receptors on the cell-surface to enhance uptake and catabolism of LDL. Second, rosuvastatin inhibits hepatic synthesis of VLDL, which reduces the total number of VLDL and LDL particles.

Pharmacodynamics

Rosuvastatin is a synthetic, enantiomerically pure antilipemic agent. It is used to lower total cholesterol, low density lipoprotein-cholesterol (LDL-C), apolipoprotein B (apoB), non-high density lipoprotein-cholesterol (non-HDL-C), and trigleride (TG) plasma concentrations while increasing HDL-C concentrations. High LDL-C, low HDL-C and high TG concentrations in the plasma are associated with increased risk of atherosclerosis and cardiovascular disease. The total cholesterol to HDL-C ratio is a strong predictor of coronary artery disease and high ratios are associated with higher risk of disease. Increased levels of HDL-C are associated with lower cardiovascular risk. By decreasing LDL-C and TG and increasing HDL-C, rosuvastatin reduces the risk of cardiovascular morbidity and mortality. Elevated cholesterol levels, and in particular, elevated low-density lipoprotein (LDL) levels, are an important risk factor for the development of CVD. Use of statins to target and reduce LDL levels has been shown in a number of landmark studies to significantly reduce the risk of development of CVD and all-cause mortality. Statins are considered a cost-effective treatment option for CVD due to their evidence of reducing all-cause mortality including fatal and non-fatal CVD as well as the need for surgical revascularization or angioplasty following a heart attack. Evidence has shown that even for low-risk individuals (with <10% risk of a major vascular event occurring within 5 years) statins cause a 20%-22% relative reduction in major cardiovascular events (heart attack, stroke, coronary revascularization, and coronary death) for every 1 mmol/L reduction in LDL without any significant side effects or risks. **Skeletal Muscle Effects** Cases of myopathy and rhabdomyolysis with acute renal failure secondary to myoglobinuria have been reported with HMG-CoA reductase inhibitors, including rosuvastatin. These risks can occur at any dose level, but are increased at the highest dose (40 mg). Rosuvastatin should be prescribed with caution in patients with predisposing factors for myopathy (e.g., age ≥ 65 years, inadequately treated hypothyroidism, renal impairment). The risk of myopathy during treatment with rosuvastatin may be increased with concurrent administration of some other lipid-lowering therapies (such as [fenofibrate] or [niacin]), [gemfibrozil], [cyclosporine], [atazanavir]/[ritonavir], [lopinavir]/ritonavir, or [simeprevir]. Cases of myopathy, including rhabdomyolysis, have been reported with HMG-CoA reductase inhibitors, including rosuvastatin, coadministered with [colchicine], and caution should therefore be exercised when prescribing these two medications together. Real-world data from observational studies has suggested that 10-15% of people taking statins may experience muscle aches at some point during treatment. **Liver Enzyme Abnormalities** Increases in serum transaminases have been reported with HMG-CoA reductase inhibitors, including rosuvastatin. In most cases, the elevations were transient and resolved or improved on continued therapy or after a brief interruption in therapy. There were two cases of jaundice, for which a relationship to rosuvastatin therapy could not be determined, which resolved after discontinuation of therapy. There were no cases of liver failure or irreversible liver disease in these trials. **Endocrine Effects** Increases in HbA1c and fasting serum glucose levels have been reported with HMG-CoA reductase inhibitors, including rosuvastatin calcium tablets. Based on clinical trial data with rosuvastatin, in some instances these increases may exceed the threshold for the diagnosis of diabetes mellitus. An in vitro study found that [atorvastatin], [pravastatin], [rosuvastatin], and [pitavastatin] exhibited a dose-dependent cytotoxic effect on human pancreas islet β cells, with reductions in cell viability of 32, 41, 34 and 29%, respectively, versus control]. Moreover, insulin secretion rates wer