{"ok":true,"entry":{"slug":"warfarin","kind":"medication","name":"warfarin","aliases":["Coumadin","Marevan"],"brands_sg":["Marevan","Apo-Warfarin"],"class":"vitamin K antagonist anticoagulant","tags":["heart-bp"],"use_for":"preventing and treating blood clots","use_after":"once a day at the same time each day (healthhub)","use_duration":null,"take_with":"with or without food · vitamin k intake kept steady","pros":["the dose is set by a regular inr blood test","sg marevan: 1 mg brown, 3 mg blue, 5 mg pink tablets","nhs: an anticoagulant alert card comes with it"],"cons":["bleeding is the main side effect (nhs)","inr tests are daily to weekly at first (nhs)","food, herbs and many medicines shift the inr"],"dose_note":"sg marevan label (sin08147p): 'The typical induction dose is 10 mg daily for 2 days but this should be tailored to individual requirements. The daily maintenance dose is usually 3 to 9 mg taken at the same time each day. The exact maintenance dose depends on the prothrombin time or other appropriate coagulation tests'; the label states no fixed maximum daily dose, and for children 'Dosage for children has not been established'; for the elderly 'As for adults, but dosage may need to be lowered' — as directed on the label or by your doctor","dosage":null,"ul_status":null,"sg_class":"prescription-only","cautions":["pregnant, or planning a pregnancy — sg label contraindicates the first and third trimesters and within 48 hours postpartum; nhs: not usually used in pregnancy","surgery, dental treatment or an injection into muscle coming up — healthhub: tell the doctor or dentist, who will advise whether therapy is interrupted; sg label contraindicates use within 72 hours of major surgery with risk of severe bleeding","severe liver or kidney disease, uncontrolled high blood pressure, stomach ulcers or a bleeding disorder — all on the sg label's contraindication list","falls, head injury or contact sports — healthhub: immediate medical attention after a fall or head injury, as serious internal bleeding may occur"],"clashes":[{"src":["nhs_warfarin_med"],"note":"nhs lists nsaids among medicines that may not mix well with warfarin","with":"nsaids including aspirin and ibuprofen"},{"src":["nhs_warfarin_med","healthhub_warfarin_food"],"note":"nhs lists all four groups; healthhub adds thyroid, cholesterol, seizure and ulcer medicines and other blood thinners","with":"antibiotics, antifungals, statins and some antidepressants"},{"src":["nhs_warfarin_med"],"note":"nhs: do not take st john's wort or vitamin k supplements while taking warfarin","with":"st john's wort and vitamin k supplements"},{"src":["hh_warfarin_vitk"],"food":true,"note":"healthhub: keep portions consistent, don’t cut them out — swings in vitamin K move your INR","with":"vitamin K foods — spinach, broccoli, kale"},{"src":["nhs_warfarin_med","healthhub_warfarin_alcohol"],"food":true,"note":"nhs: no cranberry products or grapefruit juice, and no large amounts of alcohol; healthhub caps it at one can or glass of beer or wine a day","with":"cranberry, grapefruit and alcohol"},{"src":["healthhub_warfarin_food"],"food":true,"note":"healthhub (sg): any form of traditional or herbal remedy is to be avoided — ginseng soup, herbal bak kut teh, herbal jelly are the examples given","with":"chinese herbal soups and remedies"}],"sources":[{"id":"hsa_register","url":"https://data.gov.sg/api/action/datastore_search?resource_id=d_767279312753558cbf19d48344577084&limit=6000","label":"HSA — Listing of Registered Therapeutic Products (data.gov.sg dataset d_767279312753558cbf19d48344577084), Forensicclassification column; all 5,511 rows pulled once via the datastore_search API and filtered locally, 27 Aug 2026","quote":"MAREVAN TABLET 1 mg SIN08146P | Prescription Only; MAREVAN 3 mg SIN08019P; MAREVAN 5 mg SIN08147P; Apo-Warfarin 1mg SIN13515P; 2mg SIN13516P; 5mg SIN13517P — all 6 warfarin rows 'Prescription Only'; no COUMADIN row.","accessed":"2026-08-27"},{"id":"ndf_marevan","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin08147p/","label":"MOH National Drug Formulary (Singapore) — MAREVAN TABLET 5 MG (NEW ZEALAND) [SIN08147P], warfarin sodium, Apex Pharma Marketing — product info and forensic classification","quote":"WARFARIN SODIUM - 5 MG … TABLET … Forensic Classification: PRESCRIPTION ONLY MEDICINES … Anatomical Therapeutic Chemical (ATC) code B01AA03 … Prescription-only Medicines with Exemptions for Supply without Prescription: NA","accessed":"2026-08-27"},{"id":"ndf_marevan_ind","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin08147p/","label":"MOH National Drug Formulary (Singapore) — MAREVAN [SIN08147P], indications","quote":"Prophylaxis of systemic embolisation in patients with rheumatic heart disease and atrial fibrillation. Prophylaxis of thromboembolism after insertion of prosthetic heart valves. Prophylaxis and treatment of venous thrombosis and pulmonary embolism. Transient attacks of cerebral ischaemia.","accessed":"2026-08-27"},{"id":"ndf_marevan_dose","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin08147p/","label":"MOH National Drug Formulary (Singapore) — MAREVAN [SIN08147P], dosage and administration","quote":"The typical induction dose is 10 mg daily for 2 days … The daily maintenance dose is usually 3 to 9 mg taken at the same time each day. The exact maintenance dose depends on the prothrombin time","accessed":"2026-08-27"},{"id":"ndf_marevan_ci","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin08147p/","label":"MOH National Drug Formulary (Singapore) — MAREVAN [SIN08147P], contraindications","quote":"Warfarin is contraindicated in: … Clinically significant bleeding, Within 72 hours of major surgery with risk of severe bleeding, Within 48 hours postpartum, Pregnancy (first and third trimesters) … Severe hepatic or renal disease … hypertension, gastrointestinal ulcerations","accessed":"2026-08-27"},{"id":"healthhub_warfarin","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/warfarin","label":"HealthHub (MOH Singapore) — Warfarin, last reviewed 17 October 2025 (uses, brand, INR monitoring, administration)","quote":"Warfarin is an anticoagulant … It works by blocking the action of Vitamin K in the liver … The most common brand available in Singapore is Marevan®. There are 3 colours and strengths: 1mg (brown), 3mg (blue), 5mg (pink)","accessed":"2026-08-27"},{"id":"healthhub_warfarin_food","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/warfarin","label":"HealthHub (MOH Singapore) — Warfarin, dietary and medication interactions section","quote":"A change in the Vitamin K intake from your diet will affect the INR result … Avoid any form of traditional or herbal remedies (e.g. ginseng soup, herbal “Bak Kut Teh”, herbal jelly)","accessed":"2026-08-27"},{"id":"nhs_warfarin","url":"https://www.nhs.uk/medicines/warfarin/","label":"NHS medicines A–Z — Warfarin (page last reviewed 24 February 2026)","quote":"The main side effect of warfarin is an increased risk of bleeding … blood tests every day or every few days … only need a test every 12 weeks once you're on a stable dose … an anticoagulant alert card","accessed":"2026-08-27"},{"id":"nhs_warfarin_med","url":"https://www.nhs.uk/medicines/warfarin/","label":"NHS medicines A–Z — Warfarin, taking it with other medicines, food and drink","quote":"NSAIDs, such as ibuprofen or aspirin … antibiotics … antidepressants … medicines for fungal infections … statins … Do not take the herbal remedy St John's wort or vitamin K supplements … do not have cranberry juice … grapefruit juice","accessed":"2026-08-27"},{"id":"healthhub_warfarin_alcohol","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/warfarin","label":"HealthHub (MOH Singapore) — Warfarin, alcohol advice within the dietary interactions section","quote":"Avoid excessive alcohol consumption. It is advisable to take no more than 1 can/glass of beer or wine per day. Avoid strong alcoholic drinks (e.g. whisky, brandy) as this can cause changes to the effect of warfarin.","accessed":"2026-08-27"},{"id":"hh_warfarin_vitk","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/warfarin","label":"HealthHub SG — Warfarin (vitamin K and diet)","quote":"Maintain a consistent diet in terms of your daily portions of vitamin K-rich food to ensure consistency in Vitamin K intake … It is not necessary to avoid these foods entirely as many of them are good for health.","accessed":"2026-08-29"}],"brand_certs":null,"updated_at":"2026-08-29T16:19:33.131849+08:00"},"disclaimer":"kozen-x is not a medical device and does not give medical advice. it lists what published sources have written down. absence of a record is not the same as safe."}