Monitoring immune-modulating drugs used in dermatology

Introduction

Refer to standard texts and locally approved datasheets for detailed pharmacology and therapeutics about the immune-modulating drugs discussed here.

Second-line drugs commonly used in dermatology (on- or off-label) include:

• Methotrexate
  • The dose is 5–30 mg once weekly (oral or subcutaneous)
  • Folic acid 5 mg is often also prescribed
• Azathioprine
  • Dose is 1–3 mg/kg/day
  • Taken 1 hour before or 3 hours after food
• Ciclosporin
  • Dose is 2.5–5 mg/kg/day in 2 divided doses
  • Caution if changing brand
• TNFα inhibitors (biologics)
  • A loading dose is usual
  • A maintenance dose of etanercept is 50 mg sc every week
  • A maintenance dose of adalimumab is 40 mg sc every two weeks
  • A maintenance dose of infliximab is 5 mg/kg IV every eight weeks
  • A maintenance dose of ustekinumab is 45 or 90 mg sc every 12 weeks
  • A maintenance dose of secukinumab is 300 mg every four weeks

These are prescribed by specialists, but other health professionals may be involved in the patient’s care. They should be aware at least of indications, contraindications, adverse effects and monitoring requirements.

Indications for immune-modulating drugs

Immune modulating drugs are used for diverse chronic inflammatory skin diseases that are not adequately controlled in other ways. The skin disease should be severe or have a severe functional or psychosocial impact on the patient.

Examples of suitable conditions

• Chronic plaque psoriasis
• Atopic eczema
• Hand dermatitis
• Chronic photosensitivity dermatitis
• Lichen planus
• Bullous pemphigoid
• Hidradenitis suppurativa
• Chronic spontaneous urticaria
• Drug-induced nummular dermatitis

Pre-treatment evaluation

The patient is assessed to determine:

• The disease is one that is expected to respond to the drug
• The extent and severity of the disease is recorded
  • PASI score for chronic plaque psoriasis
  • SCORAD or EASI for atopic eczema
• The impact of the disease is recorded
  • DLQI (dermatology life quality index)
• The patient wishes to receive the medication and can be expected to comply with monitoring instructions
• Impact of patient comorbidities
  • Regular dental hygiene
• Potential contraindications to treatment
• Vaccinations are up to date
• Vaccinations may be less effective on immune suppressant

Contraindications to treatment

Pregnancy and breastfeeding

• Especially methotrexate, azathioprine

Recent vaccination with a live vaccine

• Eg, yellow fever

Non-immunity to varicella-zoster virus (chickenpox, shingles)

• Consider immunisation before treatment

Non-responsive disorder

• Azathioprine is not effective for psoriasis.
• TNFα inhibitors are not effective for dermatitis or urticaria.

Co-morbidities

• Methotrexate may be unsuitable for patients with liver or haematological disease, or for people that drink excessive alcohol.

Hypersensitivity reactions

• Azathioprine hypersensitivity takes various forms

Drug interactions are very common with these drugs

• Caution if on another immunosuppressant
• Methotrexate should not be taken while on trimethoprim/sulphamethoxazole
• Azathioprine should not be taken while on allopurinol and caution with several other drugs including warfarin
• Ciclosporin interacts with statins, erythromycin, itraconazole and others

Pre-treatment tests

• Weight, height, blood pressure
• CBC, LFT, renal function
• Hepatitis B and C serology
• Sometimes: βHCG, P3NP collagen (methotrexate), thiopurine methyltransferase (azathioprine), HIV and varicella serology, TB testing
• Sometimes: chest X-ray, transient elastography scan (methotrexate)
• Rarely: liver biopsy (methotrexate)

Follow-up visits

Follow-up visits are to determine the efficacy of treatment and any adverse events and to monitor safety.

• Efficacy of treatment
• The extent and severity of the disease is recorded
  • PASI score for chronic plaque psoriasis
  • SCORAD or EASI for atopic eczema
• The impact of the disease is recorded
  • DLQI
• Compliance with treatment and monitoring are discussed.
• Drug interactions are checked before prescribing a new medicine

Adverse events

The possible adverse events from drugs are numerous. Common ones are listed here. They may require a reduction in dose or stopping treatment.

Methotrexate

Methotrexate:

• Nausea and other gastrointestinal symptoms
• Mouth ulceration
• Haematological: especially thrombocytopenia, macrocytosis
• Abnormal liver function: raised transaminases; hypoalbuminaemia is a late effect associated with cirrhosis

Azathioprine

Azathioprine:

• Nausea and vomiting
• Abnormal liver function: cholestasis or hepatitis
• Hypersensitivity reactions: rash, lymphadenopathy
• Bone marrow suppression
• Susceptibility to infection including opportunistic infections
• With long-term use
  • Increased risk of skin cancer

Ciclosporin

Ciclosporin:

• Hypertension
• Renal dysfunction
• Nausea
• Ankle oedema
• Tremor
• Paraesthesias
• Susceptibility to infection including opportunistic infections
• With long-term use:
  • Increased risk of skin cancer
  • Gingival enlargement
  • Hypertrichosis

Biologics

Biologics

• Injection site or infusion reactions
• Susceptibility to infection, especially during the first year of treatment
  • Tuberculosis and opportunistic infections
• Various autoimmune diseases are reported
• Secondary failure after initial response
• Increased risk of skin cancer

Safety monitoring

• Weight
• Blood pressure (ciclosporin)
• CBC, LFT
• Renal function (ciclosporin)
• Sometimes: βHCG, P3NP collagen (methotrexate)
• Sometimes: 6-thioguanine nucleotide (azathioprine)
• Sometimes: transient elastography scan (methotrexate)
• Rarely: liver biopsy (methotrexate)

People on long-term treatment with immune modulating drugs should undergo full body examination in case of skin cancer.