Anticoagulants: what the family of an older person should know
Types of anticoagulants, signs of bleeding, interactions, missed doses and dosage systems: the essentials for families who care.
In short
- There are two groups of anticoagulants: vitamin K antagonists such as Sintrom, which need INR tests, and direct anticoagulants, which do not need them routinely.
- The family should watch for bleeding with no clear cause and always seek advice after a heavy fall or a blow to the head.
- No anti-inflammatory, supplement or new medicine should be given without asking the doctor or pharmacist.
- A double dose should never be taken to make up for a missed one: each anticoagulant has its own rule in the leaflet.
If your father or mother takes an anticoagulant, the most important things for the family to know are that the main risk is bleeding, that falls and blows to the head need prompt medical advice, and that no medicine should be added without asking.
We explain the types of anticoagulants, the warning signs, the most common interactions and what to do about missed doses, always based on the official leaflets.
What is an anticoagulant and what types are there?
An anticoagulant is a medicine that makes the blood take longer to clot, to prevent clots, embolisms and strokes. In older people it is mainly prescribed for atrial fibrillation, deep vein thrombosis or pulmonary embolism.
Two main groups are used in Spain, and the family should know which one their relative takes because the practical rules differ:
| Vitamin K antagonists | Direct oral anticoagulants (DOACs) | |
|---|---|---|
| Examples | Acenocoumarol (Sintrom), warfarin | Apixaban, rivaroxaban, dabigatran, edoxaban |
| Monitoring | Regular clotting blood tests (INR) to adjust the dose | No routine INR, but regular medical reviews |
| Dose | May change from one test to the next | Fixed, once or twice a day depending on the drug |
| Diet | A steady intake of vitamin K is advised | Less affected by diet |
| Missed doses | According to the leaflet: take it as soon as possible unless the next dose is nearly due | Each drug has its own rule; never a double dose |
Which signs of bleeding should the family watch for?
The most important side effect of anticoagulants is bleeding. The family should look out for bleeding with no clear cause and for any fall or blow to the head, and contact the doctor straight away, because internal bleeding may cause few symptoms at first.
- Bleeding from the gums or nose that has no clear cause or is hard to stop.
- Blood in the urine, black or bloody stools, or vomiting blood.
- Large or numerous bruises, or bruises with no injury.
- New severe headache, dizziness or weakness.
- A heavy fall or a blow to the head, even if the person seems fine.
MedlinePlus also advises telling every professional, including the dentist, that the person takes an anticoagulant, and asking the prescribing doctor before any procedure. Because falls are especially dangerous in these cases, we also recommend reading which medicines increase the risk of falls.
Which medicines, foods and products can interfere?
Many medicines can increase or reduce the effect of an anticoagulant, and some very common ones are listed in the leaflets. The rule for the family is simple: do not give anything new, even without a prescription or from a health food shop, without first asking the doctor or pharmacist.
- Anti-inflammatories (NSAIDs) and aspirin: the Sintrom leaflet lists them among those that increase its effect.
- Paracetamol: also appears in the Sintrom leaflet among medicines that can strengthen it; ask before using it regularly.
- Herbal remedies and supplements: some, such as ginkgo or St John's wort, can interfere.
- Foods rich in vitamin K (green leafy vegetables, for example): with vitamin K antagonists they do not need to be cut out, but the amount should stay similar each week.
- Alcohol: the Sintrom leaflet advises avoiding it.
For a broader view, see our article on drug interactions in older people.
What should you do if a dose is missed or doubled?
With an anticoagulant, missing doses raises the risk of clots and doubling them raises the risk of bleeding. That is why a double dose should never be taken to make up, and the right thing is to follow the rule in that specific medicine's leaflet or call the pharmacy.
The rules are not the same for every drug. The Sintrom leaflet says to take the missed dose as soon as possible, unless the next one is nearly due. The Pradaxa leaflet allows it to be taken up to 6 hours before the next dose. The Eliquis leaflet, for a medicine taken twice a day, gives different instructions for the morning and evening doses.
If you suspect your relative has taken an extra dose, do not wait to see if symptoms appear: call the doctor, the pharmacist or the Spanish Toxicology Information Service, and go to A&E if there is bleeding.
Can they go into a dosage system (SPD)?
In general, oral tablets and capsules can be prepared in a personalised dosage system (SPD), but the decision always lies with the pharmacist, who checks the technical data sheet of each medicine. Some anticoagulants have special storage requirements.
For example, the Pradaxa (dabigatran) leaflet states that the capsules must be kept in the original packaging to protect them from moisture and must not be opened. In such cases the pharmacy will decide whether it can go in the blister pack or should be taken separately from its own pack. With acenocoumarol, whose dose may change after each INR test, it is vital that the pharmacy receives the updated dosage in time. You can learn more about this system in what an SPD is.
A practical example: Mercedes and her Sintrom
Take the case of Mercedes, 81, who takes acenocoumarol for atrial fibrillation along with six other medicines. Her son notices that she sometimes cannot remember whether she has taken her evening Sintrom and that, after her last test, the dose changed but she carried on with the old one.
The sensible steps would be to write each new dosage on a single, visible calendar, tell the pharmacy after every test so the prepared medication reflects the change, check with the pharmacist which painkiller she can take for her arthritis, and keep the card or report stating that she is on anticoagulants close at hand.
How can IMA Health help?
At IMA Health we coordinate with a specialised pharmacy so that your relative's medication is prepared by day and time of each dose, with home delivery and personalised follow-up. When the doctor changes a dosage, we make sure the pharmacy receives it so the prepared medication stays up to date.
Sources
- CIMA (AEMPS): Sintrom 4 mg leaflet (acenocoumarol)
- CIMA (AEMPS): Eliquis 5 mg leaflet (apixaban)
- CIMA (AEMPS): Pradaxa 150 mg leaflet (dabigatran)
- MedlinePlus: taking warfarin (Spanish edition)
This article is for information only and does not replace advice from your doctor or pharmacist.