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IL-1 Receptor Antagonist Pregnancy: Available data from retrospective studies and case reports in pregnant women are insufficient to identify a drug-associated risk of major birth defects, miscarriage, or maternal and fetal adverse events. Animal reproduction studies showed no evidence of fetal harm at doses up to 25 times the maximum recommended human dose. There are risks to mother and fetus from active rheumatoid arthritis or CAPS.

Anakinra

Brand names: Kineret

Anakinra is a recombinant interleukin-1 receptor antagonist used in rheumatoid arthritis and in several autoinflammatory conditions such as cryopyrin-associated periodic syndromes and Still's disease.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Rheumatoid arthritis: 100 mg per day
Route: Subcutaneous injection
Frequency: Once daily, administered at approximately the same time every day
Max: Rheumatoid arthritis: higher doses than 100 mg/day did not result in a higher response. Cryopyrin-Associated Periodic Syndromes (NOMID) and DIRA: maximum 8 mg/kg daily.
US labelling (Kineret) - no UK SPC posology was retrieved in this bundle, so verify against the UK SPC before use. Cryopyrin-Associated Periodic Syndromes (CAPS/NOMID): recommended starting dose 1-2 mg/kg daily, individually adjusted in 0.5 to 1 mg/kg increments to a maximum of 8 mg/kg daily to control active inflammation; once-daily administration is generally recommended but the dose may be split into twice-daily administrations. Deficiency of Interleukin-1 Receptor Antagonist (DIRA): recommended starting dose 1-2 mg/kg daily, adjusted in 0.5 to 1 mg/kg increments to a maximum of 8 mg/kg daily. Each prefilled syringe is for single use and any unused portion after each dose should be discarded; the graduated syringe allows doses between 20 mg and 100 mg and does not allow doses lower than 20 mg. Rotate injection sites to reduce the risk of injection site reactions and injection site amyloid deposits. Neutrophil counts should be assessed before starting, then monthly for 3 months and quarterly thereafter for up to 1 year.

Paediatric dose

Route: Subcutaneous injection
Frequency: Once daily (the dose may be split into twice-daily administrations)
Max: 8 mg/kg daily
The source states a range rather than a single per-kg value. NOMID/CAPS and DIRA: recommended starting dose 1-2 mg/kg daily, adjusted in 0.5 to 1 mg/kg increments to a maximum of 8 mg/kg daily. In the NOMID study (36 paediatric patients: 13 under 2 years, 18 aged 2-11, 5 aged 12-17) a starting dose of 1-2 mg/kg/day was used in all age groups and an average maintenance dose of 3-4 mg/kg/day was adequate to maintain clinical response, with a higher dose occasionally required in severely affected patients. In DIRA (9 paediatric patients aged 1 month to 9 years) most patients received a starting dose of 1 to 2 mg/kg/day, with doses up to 7.5 mg/kg/day given. Safety and effectiveness in juvenile rheumatoid arthritis have not been established (studied at 1 mg/kg subcutaneously daily, up to a maximum dose of 100 mg). The prefilled syringe does not allow doses lower than 20 mg to be administered. US labelling - verify against a children's formulary and the UK SPC.

Dose adjustments

Renal

Consider administering the prescribed dose every other day in patients with severe renal insufficiency or end stage renal disease (creatinine clearance below 30 mL/min, as estimated from serum creatinine levels). Anakinra is substantially excreted by the kidney and the risk of toxic reactions may be greater in patients with impaired renal function.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Known hypersensitivity to E. coli-derived proteins, to anakinra (Kineret), or to any component of the product

Side effects

  • Injection site reactions (most common adverse reaction and the commonest reason for withdrawing from studies)
  • Upper respiratory tract infection
  • Headache
  • Nausea, diarrhoea and abdominal pain
  • Worsening of rheumatoid arthritis, arthralgia, sinusitis and flu-like symptoms
  • Serious infections and neutropenia (particularly when used in combination with TNF blocking agents)

Interactions

  • TNF blocking agents: a higher rate of serious infections has been observed with concurrent anakinra and etanercept than with etanercept alone, and 2% of patients treated concurrently developed neutropenia (ANC below 1 x 10^9/L). Use of anakinra in combination with TNF blocking agents is not recommended
  • No drug-drug interaction studies in human subjects have been conducted; rat toxicology and toxicokinetic studies showed no alteration in the clearance or toxicologic profile of either methotrexate or anakinra when given together
  • Live vaccines should not be given concurrently with anakinra

Clinical monograph

How it works

It competitively blocks the interleukin-1 receptor, neutralising the pro-inflammatory effects of IL-1alpha and IL-1beta.

Prescribing in practice

  • It increases the risk of serious infection, so screen for and treat active infection before starting and avoid combining with TNF inhibitors.
  • Administered by subcutaneous injection, usually once daily.
  • Injection-site reactions are common, and neutropenia can occur.

Monitoring

Monitor full blood count (including neutrophil count) periodically and remain vigilant for signs of infection.

Counselling the patient

  • Report signs of infection such as fever, sore throat, or persistent cough promptly.
  • Injection-site redness or itching is common and usually settles; rotate injection sites.
  • Ensure vaccinations are up to date and avoid live vaccines while treated.

Evidence & guidelines

Anakinra is an established IL-1 blocking therapy supported by trial data in rheumatoid arthritis and autoinflammatory syndromes; consult the SPC.

Reference: NICE TA71; BSR biologics guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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