Your dialysis medicines, explained

Why there are so many

A dialysis machine removes waste and fluid. It does not make hormones. So everything your kidneys used to do chemically, rather than mechanically, has to be replaced with tablets and injections: the hormone that tells your marrow to make blood, the activation of vitamin D, the control of phosphate, the control of acid. That is why the tablet count is high, and it is why the medicines are not optional extras around the edges of dialysis. They are part of the treatment.

Phosphate binders

What they do. They bind the phosphate in the food that is in your gut, so it passes out in the stool instead of being absorbed into your blood.

How they are taken, and this is the part that matters. With food. Every time you eat. Including snacks.

The types

• Calcium-based binders(calcium acetate, calcium carbonate). Effective and cheap. But they add a calcium load, and KDIGO's 2017 update recommends restricting their dose in adults with advanced kidney disease and on dialysis, because of concern about calcium loading and hardening of the blood vessels.
• Non-calcium binders (sevelamer, lanthanum carbonate, ferric citrate, sucroferric oxyhydroxide). No calcium load. The iron-based ones can also raise your iron stores, which is sometimes useful and sometimes needs watching.
• Aluminium-based binders exist but are avoided for long-term use, because aluminium accumulates and causes bone disease and effects on the brain.

Common side effectsacross the class: constipation, nausea, bloating, dark stools with the iron-based ones, and the pill burden itself. That last one is not a trivial complaint. Binders can be the biggest part of a dialysis patient's tablet count, and swallowing a handful with every meal, for years, wears people down. It is worth saying out loud to your team, because different binders differ in how many tablets are needed.

And a point from the diet guide that belongs here too: binders exist so that you can eat enough protein. Never solve a high phosphate level by eating less protein.

Anaemia: the injections, and the tablets that may replace them

Why you are anaemic. Healthy kidneys make erythropoietin, the hormone that tells your bone marrow to produce red blood cells. Failing kidneys make too little of it. The marrow is willing, but nobody is asking it to work.

ESAs (erythropoiesis-stimulating agents)

These replace the missing signal. They are given by injection, either under the skin or into the dialysis circuit, typically weekly or less often depending on the agent.

What they do: raise your haemoglobin, reduce the need for blood transfusions, and usually improve fatigue and how much you can do.

What they do not do: improve survival. And here is the part that surprises people: pushing the blood count all the way up to normal causes harm. That is why guidelines set a ceiling as well as a floor, and why your team may seem oddly unwilling to make your blood count "normal". They are not under-treating you. They are following evidence that came from trials in which normalising haemoglobin turned out to hurt people.

Iron first. An ESA cannot build red cells out of nothing. KDIGO is clear that correctable causes of anaemia, iron deficiency above all, should be dealt with before an ESA is started.

HIF-PHIs: the newer tablets, and a genuine disagreement

There is a newer class of oral medicines (roxadustat, daprodustat, vadadustat) that treat kidney anaemia with a tablet rather than an injection. Guideline bodies do not currently agree about them, and you deserve to know that rather than being handed one position as settled fact:

• KDIGO recommends ESAs as first-line, on the grounds of long experience and established safety, and grades that recommendation weakly.
• European Renal Best Practice argues that both ESAs and the approved HIF-PHIs should be considered as options.

This is a live area of disagreement between serious people. If your team offers you one or the other, it is entirely reasonable to ask why.

Iron

Iron is the raw material for haemoglobin. Iron deficiency is very common in dialysis, for three reasons that stack up: small amounts of blood are lost in the dialysis circuit and in the constant blood tests, absorption from the gut is poor in kidney failure, and inflammation locks iron away in storage where the marrow cannot use it.

Oral iron is often poorly absorbed and poorly tolerated in kidney disease, so intravenous iron is the mainstay on haemodialysis, and it is usually given straight into the dialysis circuit, which makes it easy and painless.

Two blood tests guide it. Ferritin reflects how much iron you have in store, but it also rises with inflammation, so it can read misleadingly high. TSAT (transferrin saturation) reflects how much iron is actually available for use right now. Guidelines set both floors (below which iron is given) and ceilings (above which routine iron is withheld), because iron overload is a real concern with repeated dosing.

Vitamin D: two different medicines with one name

This confusion is extremely common, and it is worth clearing up, because the two are not interchangeable.

• Nutritional vitamin D (cholecalciferol, ergocalciferol). This is the vitamin, used to correct a simple deficiency. It still needs to be activated by the kidney before your body can use it.
• Active vitamin D and its analogues (calcitriol, alfacalcidol, paricalcitol, doxercalciferol). Failing kidneys cannot perform the final activation step, so these come pre-activated. They are used to suppress an overactive parathyroid gland, which is a different job entirely from topping up a vitamin.

Why care is needed. Active vitamin D increases the absorption of calcium and phosphate from the gut. Too much can raise calcium too high and worsen hardening of the arteries. KDIGO therefore does not recommend routine use of active vitamin D in people with advanced kidney disease who are not on dialysis, reserving it for severe and progressive parathyroid overactivity. In people on dialysis, active vitamin D, its analogues and a different class called calcimimetics (cinacalcet, etelcalcetide) are all acceptable first choices for lowering parathyroid hormone, with the choice individualised.

The others you will probably meet

• Blood pressure medicines. Still important. On haemodialysis, timing matters: some are held on dialysis days because they make a blood pressure crash during the session more likely. This is always an individual instruction. Never decide it for yourself.
• Calcimimetics(cinacalcet, etelcalcetide). They lower parathyroid hormone by making the gland's calcium sensor more sensitive. Etelcalcetide is given intravenously at dialysis, which removes one more tablet from the pile.
• Sodium bicarbonate, to correct the acid build-up that failing kidneys cause.
• Potassium binders (calcium polystyrene sulfonate, patiromer, sodium zirconium cyclosilicate). These lower potassium, and they are not the same thing as phosphate binders, though the name invites confusion.
• Treatments for itching. Uraemic itch is common, miserable, and badly under-treated. Newer agents exist. If nobody has offered you anything, ask, and keep asking.
• Statins. Worth knowing: the trials of starting a statin in people already on dialysis did not show the benefit seen in other groups. Guidance on starting one in dialysis therefore differs from guidance for the general population, though people who were already taking one usually continue. If you are surprised not to be offered a statin, that is the reason, and it is a fair question for your team.
• Heparin during each haemodialysis session, to stop the circuit clotting.

Medicines to be careful with in kidney failure

This is a genuinely useful list, and it is worth learning, because most of these are things you can buy yourself without anyone asking about your kidneys.

• Anti-inflammatory painkillers: ibuprofen, diclofenac, naproxen. Avoid them.
• Many over-the-counter cold and flu remedies, particularly soluble and effervescent tablets, which can carry a lot of sodium.
• Magnesium-containing antacids and laxatives.
• Salt substitutes, which are usually potassium chloride.
• Herbal remedies and supplements of any kind that your kidney team has not cleared, including anything sold as a kidney cleanse or a kidney tonic.

And the standing rule, which is the most valuable sentence on this page: tell every doctor, every dentist, every pharmacist and every paramedic that you have kidney failure and are on dialysis, before they prescribe anything. The doses of many perfectly ordinary medicines, including some antibiotics and some diabetes medicines, have to be adjusted in kidney failure. The prescriber cannot know unless you tell them, and they will not mind being told twice.

Getting the best out of your medicines

• Ask for a medicines review with the renal pharmacist. They are part of the team, and most people never ask to see them.
• Take an accurate, current list to every appointment. Not a memory, a list.
• Say it if the pill burden is beating you. There is often something that can be changed, and there is nothing to be gained by suffering quietly and skipping doses instead.
• Ask what each medicine is for. People take medicines they understand. They quietly abandon ones they do not.