Medical Oncologist
CION Cancer Clinics
Blood thinner injections after cancer surgery | CION Cancer Clinics
The injections lower the chance of a blood clot forming in a leg vein after cancer surgery. Both cancer and a major operation make clots more likely, and a clot that travels to the lungs can be dangerous. Enoxaparin, often sold as Clexane, is a common choice, given under the skin of the tummy. Your surgeon decides whether you need it and for how long. CION Cancer Clinics’ surgical oncologists in Hyderabad can talk this through with you.
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Medically reviewed by Dr. Muralidhar MuddusettyConsultant Surgical Oncologist · MBBS (AIIMS), MS (Surgery, AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh) · last reviewed September 2026, next review due September 2027
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On this page
- Why are blood thinner injections given after cancer surgery?
- What else is used alongside the injection?
- How do you give the injection at home?
- What do the words on the discharge summary mean?
- What do families worry about with these injections?
- Who may not be given the injections, and what can this page not tell you?
- Common questions about blood thinner injections after surgery
The short answer
Why are blood thinner injections given after cancer surgery?
They are given to stop a clot forming in the deep veins of your legs or pelvis while you recover. Cancer makes the blood more likely to clot, and so does a large operation followed by days of lying still. Together they raise the risk more than either does alone.
Why a leg clot matters
A clot in a deep leg vein is called a deep vein thrombosis, or DVT. It can cause a painful, swollen calf. The bigger danger is a piece breaking off and travelling to the lungs, called a pulmonary embolism. That can cause sudden breathlessness and chest pain, and it needs emergency care.
Why an injection rather than a tablet
The usual medicine is a low molecular weight heparin, such as enoxaparin (often sold as Clexane) or dalteparin (Fragmin). It goes under the skin, starts working quickly and wears off predictably, so it can be timed around drains, epidurals and wound checks. Some people are given fondaparinux or a tablet blood thinner instead.
These injections lower the chance of a new clot. A clot that has already formed is treated with a different plan.More than one measure
What else is used alongside the injection?
Most plans combine several measures. The injection is only one of them, and the others matter just as much.
Walking early
Getting out of bed and walking, even a few steps, keeps blood moving through the leg veins. Nurses and physiotherapists encourage it as soon as they judge it safe.
Family can help by
- Walking beside the patient on the ward
- Not keeping them in bed "to rest"
Compression stockings
Firm elastic stockings squeeze the calves gently. They are measured to fit and usually worn while you are less mobile. They do not suit people with poor circulation in the legs or some skin conditions.
Calf pumps
Inflatable sleeves around the lower legs squeeze and release in turn. They do the calf muscle's work while you are in theatre or still in bed.
Drinking and leg exercises
Once you are allowed to drink, enough fluid keeps the blood from thickening. Moving your ankles up and down and circling your feet in bed also helps.
Not sure whether this applies to you?
Ask an oncologistAt home
How do you give the injection at home?
A nurse will show you or a family member before discharge. This is a reminder of what they teach, not a replacement for it.
Prepare
Wash your hands. Check the name, the strength and the expiry date against your discharge summary. Most come as ready-filled syringes. Do not push out the small air bubble unless you were told to.
Choose the spot
Use the skin of the tummy, a few finger-widths away from the belly button and away from the wound, stoma or drain sites. Change sides each time so one area does not become sore.
Inject
Pinch a fold of skin gently, push the needle straight in fully and press the plunger slowly. Keep the fold pinched until the syringe is empty, then take the needle out.
Finish safely
Do not rub the spot, as this increases bruising. Put the used syringe in a hard plastic bottle with a lid, and ask the hospital how to dispose of it. Never reuse a syringe.
On your discharge summary
What do the words on the discharge summary mean?
- DVT
- Deep vein thrombosis. A clot in a deep vein, usually in the calf or thigh.
- PE
- Pulmonary embolism. A clot that has travelled to the blood vessels of the lungs.
- VTE
- Venous thromboembolism. The name that covers both DVT and PE.
- LMWH
- Low molecular weight heparin. The group of injections that includes enoxaparin and dalteparin.
- Extended course
- Continuing the injections at home after discharge. It is often advised after major operations on the tummy or pelvis for cancer.
- Platelets
- Blood cells that help clotting. They are checked with a blood test, because a low platelet count changes the plan.
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One thing that cannot wait
Go to the nearest emergency department the same day if you develop sudden breathlessness, chest pain that is worse when you breathe in, or you cough up blood. Tell your surgical team urgently about a painful, swollen or warm calf, heavy bleeding from the wound, black or bloody motions, or a severe headache. Say you are on a blood thinner injection. Do not decide on your own to skip or double an injection.
Commonly believed
What do families worry about with these injections?
"The bruises mean something is wrong."
Small bruises around the injection spot are very common and usually harmless. Changing the spot each time and not rubbing it helps. A large, painful or spreading swelling, or bleeding that will not stop with pressure, should be reported to the team.
"Once he is walking, the injections can stop."
Walking helps, but the risk from cancer and a large operation lasts beyond the first days of recovery. Your surgeon sets how long the injections continue, and finishing the prescribed course matters even when you feel well.
"A blood thinner will make the wound bleed open."
The injections are chosen and timed with the wound in mind, and the surgeon checks for bleeding before starting them. Serious wound bleeding is uncommon. If a dressing soaks through, press firmly on it and call the team.
"Only elderly or overweight people get clots."
Cancer itself raises the risk at any age. Young, active people having major cancer surgery are also given protection, because the operation and the disease together matter more than how fit someone looks.
Being straight with you
Who may not be given the injections, and what can this page not tell you?
The injections are not right for everyone. Your surgeon weighs the chance of a clot against the chance of bleeding, and in some people the balance tips the other way.
When the team may choose differently
People with a very low platelet count, active bleeding, a recent bleed in the brain or a past reaction to heparin may be given stockings and calf pumps instead, or a different medicine. Weak kidney function changes the choice and sometimes the strength. If you have an epidural or spinal catheter, the injection is timed carefully around when it goes in and comes out.
If you already take a blood thinner
If you take Acitrom, warfarin, apixaban (Eliquis) or rivaroxaban (Xarelto) for your heart or an earlier clot, your plan is different. The injection may cover the gap while the tablet is paused. Your surgeon and the doctor who prescribes the tablet decide when it comes back.
What this page cannot tell you
It cannot tell you whether you need injections at home, for how long, or at what strength. Those depend on your operation, your weight, your kidneys and your own history of clots. Your discharge summary should state all of this. If it does not, ask before you leave.
Questions we are asked
Common questions about blood thinner injections after surgery
How long will I need the injections?
Your surgeon decides, based on the operation, how well you are moving and your own risk. Some people need them only in hospital. Others continue at home for longer after major surgery on the tummy or pelvis. Your discharge summary should state the end date clearly. If it does not, ask before you leave.
Can a family member give the injection?
Yes. Many families learn before discharge. Ask the nurse to watch you or your relative give an injection on the ward, so questions can be answered there and then. If nobody at home feels able to do it, tell the team early, as a visiting nurse or a nearby clinic may be arranged.
What if we miss an injection?
Do not give two together to catch up. Call your surgical team or the hospital pharmacy, say which injection was missed and when, and follow their advice. A single missed injection is rarely an emergency, but it should be reported rather than quietly ignored.
Can I take painkillers with the injections?
Some painkillers add to bleeding risk, including ibuprofen, diclofenac, aceclofenac and aspirin-based products. Paracetamol is often preferred, but check with the team before taking any painkiller that is not on your discharge list. Tell every doctor or dentist you see that you are on a blood thinner.
Why is my tummy covered in bruises?
Bruising around injection spots is common and usually fades on its own. Change the spot each time, avoid rubbing and press the plunger slowly. Report bruises that are large or keep spreading, bruises in places you have not injected, and bleeding from the gums or nose that does not stop.
Can I have tablets instead of injections?
Sometimes. For certain operations or people, a tablet blood thinner may be used. The choice depends on the cancer, the operation, your kidneys and your other medicines. Do not ask a chemist to swap one for the other. Any change has to come from your surgeon.
Do the syringes need to go in the fridge?
Many ready-filled syringes are kept at room temperature, away from direct sunlight and out of children's reach. Storage can differ between brands, so read the packet and ask the pharmacist if you are unsure. Do not freeze them, and do not use a syringe that looks cloudy or damaged.
Are the injections covered by Aarogyasri or insurance?
Injections given in hospital are usually part of the operation package. Injections for home may be treated differently under Aarogyasri, CGHS, ECHS, EHS or cashless insurance, and some plans count them as outpatient medicine. Ask before discharge, and call the helpline if you want help checking your own cover.
Meet the Specialists
17+ senior cancer specialists. One panel for your case.
Trained at AIIMS, Tata Memorial, and leading international centres. Combined 150+ years of experience. Every complex case is reviewed by 3+ of them — together.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
Surgical Oncologist
Surgical Oncologist
Dr. Vinay Mamidala
MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)
Surgical Oncologist
Radiation Oncologist
Radiation Oncologist
Radiation Oncologist
Hematologist
Surgical Oncologist
Dr. Vajja Sandeep Kumar
MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology
Surgical Oncologist
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Sources
- NICE — Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism (NG89)
- NHS — Deep vein thrombosis (DVT)
- NHS — Pulmonary embolism
- NHS — Anticoagulant medicines
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Eliquis, Xarelto and Newer Blood Thinners Before SurgeryIf you already take a blood thinner tabletAcitrom and Warfarin Before SurgeryHow older blood thinners are paused and restartedComplications and Red FlagsOther signs after surgery that need a call the same dayRecovery, Eating and Getting Back to LifeWalking, eating and the weeks after going home
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Unsure about the injections after discharge?
Tell us what operation was done and what is on your discharge summary. We will help you reach the right surgical team with your questions.