Purine analogue / immunosuppressant Pregnancy: Contraindicated in pregnancy (may cause congenital malformations; animal reproductive toxicity). Pregnancy must be excluded before initiation in years 1 and 2, with effective contraception during treatment and for at least 6 months after the last dose (males: prevent partner pregnancy for at least 3 months after the last dose). Breast-feeding is contraindicated during treatment and for 1 week after the last dose.

Cladribine

Brand names: Litak, Mavenclad

Cladribine is a purine nucleoside analogue cytotoxic agent used in hairy cell leukaemia and certain other lymphoid malignancies, and (as a separate oral preparation) in relapsing multiple sclerosis.

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: Multiple sclerosis (oral tablets): recommended cumulative dose 3.5 mg/kg body weight over 2 years, given as 1 treatment course of 1.75 mg/kg per year

Route: Oral

Frequency: Each yearly course = 2 treatment weeks (one at the start of month 1 and one at the start of month 2); each treatment week is 4 or 5 days of a single daily dose of 10 mg or 20 mg (one or two 10 mg tablets) depending on body weight

Max: Cumulative 3.5 mg/kg over 2 years (1.75 mg/kg per yearly course); no more than 2 tablets (20 mg) daily

Treatment must be initiated and supervised by a physician experienced in the treatment of MS. Dose distributed by body weight per treatment week (SPC Table 1): 40 to <50 kg = 40 mg/week; 50 to <60 kg = 50 mg; 60 to <70 kg = 60 mg; 70 to <80 kg = 70 mg; 80 to <90 kg = 80 mg (week 1)/70 mg (week 2); 90 to <100 kg = 90 mg/80 mg; 100 to <110 kg = 100 mg/90 mg; >=110 kg = 100 mg/100 mg. Use in patients weighing less than 40 kg has not been investigated. Do not take more than 2 tablets daily. Lymphocyte counts must be normal before year 1 and at least 800 cells/mm3 before year 2 (year 2 course may be delayed up to 6 months for lymphocyte recovery; if recovery takes longer than 6 months, discontinue). After the 2 treatment courses, no further cladribine is required in years 3 and 4. Separate from any other oral medicinal product by at least 3 hours on dosing days. Screen for HIV, tuberculosis, and hepatitis B/C before each treatment year. Tablets are uncoated and cytotoxic - swallow immediately; keep hands dry and wash after handling.

Dose adjustments

Renal

Mild renal impairment (CrCl 60-89 mL/min): no dose adjustment needed. Moderate or severe renal impairment (CrCl <60 mL/min): contraindicated (safety and efficacy not established).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; 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

Hypersensitivity to cladribine or any excipient
HIV infection
Active chronic infection (tuberculosis or hepatitis)
Immunocompromised patients, including those on immunosuppressive or myelosuppressive therapy
Active malignancy
Moderate or severe renal impairment (creatinine clearance <60 mL/min)
Pregnancy and breast-feeding

Side effects

Lymphopenia (very common, ~25.6%)
Herpes zoster / dermatomal herpes zoster and oral herpes
Decrease in neutrophil count
Hypersensitivity (pruritus, urticaria, rash; rarely angio-oedema)
Rash, alopecia

Interactions

Immunosuppressive/myelosuppressive substances (additive haematological effects; not recommended concomitantly)
Other substances affecting the haematological profile
Any other oral medicinal product should be separated by at least 3 hours on cladribine dosing days

Clinical monograph

How it works

As a deoxyadenosine analogue it is phosphorylated intracellularly and accumulates particularly in lymphocytes, disrupting DNA synthesis and repair and causing selective lymphocyte depletion and apoptosis.

Prescribing in practice

Profound and prolonged myelosuppression and lymphopenia occur, with a consequent risk of serious and opportunistic infection requiring close haematological monitoring.
It is markedly immunosuppressive; consider infection prophylaxis and avoid live vaccines during and after treatment.
Verify the correct product and route, as haematology (parenteral) and multiple sclerosis (oral) preparations and regimens differ.

Monitoring

Monitor full blood count, including lymphocyte subsets, and watch closely for febrile neutropenia and opportunistic infection.

Counselling the patient

Report fever or any sign of infection without delay, as your white cell count may be very low.
Effective contraception is advised during and for a period after treatment.
Avoid live vaccines and discuss any planned immunisations with your team.

Evidence & guidelines

Cladribine produces durable complete responses in hairy cell leukaemia and is an established option supported by long-term cohort data; consult current prescribing references for malignancy regimens.

Reference: NICE TA616; 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).

Curated clinical cross-links plus same-class fallbacks.

Pathways