Is Coumadin the safest blood thinner?
Coumadin is a Brand name for an anticoagulant (or blood thinner) drug that contains warfarin as an active ingredient. Warfarin prevents the formation of blood clots as well as their migration by inhibiting vitamin K-dependent coagulation factors.
Coumadin is indicated for: treatment and prophylaxis of venous thrombosis and pulmonary embolism as its extension, treatment and prophylaxis of thromboembolic complications associated with atrial fibrillation and/or cardiac valve replacement, reduction of recurrent myocardial infarction and thromboembolic events (such as stroke or systemic embolization) after myocardial infarction and therefore the reduction the risk of death.
Coumadin has no effects on an established thrombus, and can’t reverse ischemic tissue damage. The main targets of anticoagulant therapy are to prevent further extension of the formed blood clot and to prevent the risk of secondary thromboembolic complications that may result in serious and possibly fatal outcomes.
Despite its effectiveness, warfarin therapy has several issues. Many drugs interact with warfarin, as well as some foods (such as leaf vegetable foods because they typically contain large amounts of vitamin K1) and its activity has to be monitored by blood testing for parameter INR – International Normalized Ratio to be ensured that adequate safe dose is taken.
If INR value is high, patients are predisposed to an increased risk of bleeding, while low INR values indicates that the dose of warfarin is uneffective to protect against thromboembolic events.
Other Brand names for warfarin products on the market are: Jantoven, Marevan, Waran and Warfant.
What is Zocor?
Zocor is a Brand name for a drug that contain simvastatin as an active ingredient which belongs to a group of drugs called HMG CoA reductase inhibitors, also known as “statins.” Simvastatin works by reducing the levels of “bad” cholesterol – LDL (low-density lipoprotein), and triglycerides in the blood, while increasing levels of “good” cholesterol – HDL (high-density lipoprotein).
It is also used to reduce the risk of heart attack, stroke and other heart complications in people with diabetes, coronary heart disease, or other risk factors. Zocor is used in adults and children who are at least 10 years old.
Other Brand names for drugs containing simvastatin as an active ingredient are: Cholestat, Lipex, Sinvacor, Sivastin, Sorfox and Statex.
How does Coumadin and Zocor work in the body?
Warfarin works by inhibiting the enzyme activity of vitamin K reductase, which results in depletion of vitamin KH2 – the reduced form of vitamin K. Vitamin K is a cofactor for the carboxylation reactions of glutamate residues of vitamin K-dependent proteins, so this inhibition limits the gamma-carboxylation reactions and activation of the vitamin K-dependent coagulant proteins.
Therefore, the synthesis of vitamin K-dependent coagulation factors II, VII, IX, and X and anticoagulant proteins S and C is inhibited. Decreased levels of 3 of the 4 vitamin K-dependent coagulation factors (II, VII, and X) results in decreased prothrombin levels in blood and a decrease in the amount of thrombin generated and bound to fibrin. This reduces the thrombogenicity of clots.
Simvastatin is a lipid-lowering drug that is synthetically derived from the fermentation of fungi Aspergillus terreus. It is a potent competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, rate-limiting enzyme in biosynthesis of cholesterol.
Interference with this enzyme activity reduces the quantity of mevalonic acid, a precursor of cholesterol. It may also interfere with steroid hormone production. Due to the induction of hepatic LDL receptors, it increases breakdown of LDL cholesterol.
Can patients take Coumadin and Zocor together?
Patients should never take Coumadin with Zocor without medical supervision. Warfarin is being co-prescribed increasingly with HMG-CoA inhibitors, such as simvastatin, for their benefits in reducing the risk of coronary events and stroke.
Many mechanisms for the interaction between Coumadin and Zocor have been postulated, including inhibition of warfarin metabolism, alteration in vitamin K availability, or protein binding displacement.
However, there are no relevant clinical data to confirm any of these. In conclusion, studies have found that concomitant simvastatin therapy results in alterations in warfarin pharmacokinetics, most likely through inhibition of the CYP450 enzymes: CYP2C9 and CYP3A4 which are responsible for the metabolism of warfarin rather than by modification of its pharmacodynamics.
Health professionals should be aware of the interaction between these commonly co-prescribed drugs and patients receiving warfarin should be monitored carefully when concurrent therapy with simvastatin is initiated to avoid over-anticoagulation and the high risk of bleeding.
The table below shows the incidence of side effects after Coumadin and Zocor administration in recommendable doses. The incidence can be increased if these drugs are taken together or overdosed.
|Frequency not defined||Cholesterol embolus syndrome, Abdominal pain, Intraocular hemorrhage, Alopecia, Rash, Pruritus, Headache, Lethargy, Taste disturbance, Tissue necrosis, Hematuria, Anemia, Hepatitis, Respiratory tract bleeding, Hypersensitivity reaction, Hemorrhage, “Purple toe” syndrome, Increased fracture risk with long-term usage, Dizziness, CPK elevation, Transaminases increased, Upper respiratory infection, Constipation, Flatulence, Myalgia, Eczema, Abdominal pain, Vertigo|
Special precautions and warnings during Coumadin and Zocor administration:
- Patients should tell their doctor and pharmacist if they are allergic to Coumadin or Zocor, or any other medications, or any of the ingredients in these products.
- Patients should tell their doctor and pharmacist what prescription and nonprescription medicines, nutritional supplements, vitamins and herbal preparations they are taking or plan to take. There are many drugs that have interactions with warfarin and those interactions can cause serious side effects.
- Patients should tell their doctor and pharmacist if they have or have ever had diseases such as: atherosclerosis, diabetes, some liver or kidney disease, bleeding problems, porphyria, cardiovascular disease such as chest pain (angina), arrhythmias, high blood pressure or heart attack; an underactive adrenal or pituitary gland, or any condition that makes swallow difficult.
- Patients using Coumadin should tell their doctor and pharmacist what herbal or botanical products they are taking, especially if they are using coenzyme Q10 prparation, Echinacea, Ginkgo biloba, garlic, goldenseal, ginseng, and St. John’s wort. There are also many other herbal or botanical products which might affect body’s response to Coumadin.
- Patients should tell their doctor if they have or have ever had diabetes. Also they should tell their doctor if they have an infection, a gastrointestinal illness such as diarrhea, or sprue or an indwelling catheter.
- Patients should also tell their doctor if they are pregnant or plan to become pregnant or if they are breast-feeding. If they become pregnant while using these drugs they should call their doctor immediately. Pregnant women should not take warfarin unless they have a mechanical heart valve, but only with medical supervision. Coumadin may harm the fetus.
- If patients should have surgery, including dental surgery, they should tell their doctor or dentist that they are using these drugs. Doctor may tell to stop taking warfarin before the surgery or procedure or change your dosage of warfarin before the surgery or procedure.
- Cigarette smoking may decrease the effectiveness of Coumadin.
- In rare cases, simvastatin can cause a serious condition that result in skeletal muscle tissue breakdown, leading to kidney failure. Patients should call doctor immediately if they experience unexplained muscle pain, tenderness, or weakness especially if they also have unusual tiredness, fever and dark colored urine.
- Before taking Zocor, patients should tell their doctor if they have ever had kidney or liver disease thyroid disorder or diabetes if they are Chinese descent, or if they drink more than 2 alcoholic beverages daily.
- Grapefruit and grapefruit juice may interact with simvastatin leading to potentially dangerous effects. Patients should not consume grapefruit products while taking this medicine.