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Drug-induced pruritus

Author: Dr Tim Aung, Primary Care Practitioner, Star Medical Centre, Brisbane, QLD, Australia. DermNet NZ Editor in Chief: Adjunct A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. Copy edited by Gus Mitchell/Maria McGivern. April 2019.


What is drug-induced pruritus?

Pruritus is the medical name for itching. Drug-induced pruritus is an itch caused or triggered by medication. There are various itchy drug eruptions, but generally, the term ‘drug-induced pruritus’ implies that no primary rash is present — just scratch marks.

  • Pruritus can begin within hours or up to several weeks after the drug responsible has first been administered.
  • Pruritus can be classified as acute (ie, present for < 6 weeks) or chronic (ie, present for > 6 weeks).
  • It can be localised or generalised.
  • Following the cessation of the causative drug, the itch may persist for days to months before resolving.
Scratching due to drug-induced pruritus

Who gets drug-induced pruritus?

The epidemiology of drug-induced pruritus is unknown. Generally, adverse drug reactions are more common in older patients and in patients taking multiple medicines.

What is the cause of drug-induced pruritus?

The cause of drug-induced pruritus is often unknown and depends on the drug. It may involve:

  • A genetic predisposition
  • Vasodilation
  • Phototoxicity
  • Neural pathways
  • Cutaneous deposition of drugs or their metabolites
  • Dry skin
  • Cholestatic liver injury
  • Another unknown mechanism [1,2].

Which drugs cause pruritus?

The most commonly reported drugs to cause pruritus are opioids (especially during spinal anaesthesia), chemotherapeutic agents, and chloroquine (affecting 60–70% of black Africans prescribed this medicine).

The main groups of drugs that cause pruritus through various mechanisms are listed below.

Antimicrobials and antibiotics

Antimicrobials and antibiotics that cause pruritus include:

Cardiovascular medicines

Cardiovascular medicines that can cause pruritus include:

  • Amlodipine
  • Diltiazem
  • Verapamil
  • Clonidine
  • Methyldopa
  • Amiodarone
  • Captopril
  • Enalapril
  • Lisinopril
  • Candesartan
  • Irbesartan.

Metabolic medicines

Metabolic medicines that can cause pruritus include:

  • Metformin
  • Gliclazide
  • Allopurinol.

Neuroleptic and psychotropic drugs

Neuroleptic and psychotropic drugs (used to treat psychosis) that can cause pruritus include:

Opioids and analgesics

Opioids and analgesics that can cause pruritus include:

  • Morphine
  • Codeine
  • Fentanyl
  • Oxycodone
  • Tramadol
  • Aspirin.

Steroids and hormones

Steroids and hormones that can cause pruritus include:

Chemotherapeutics and biological agents

Chemotherapeutic and biological agents that can cause pruritus include:

Other drugs

Other drugs that can cause pruritus include:

  • Enoxaparin
  • Hydroxyethyl starch (a plasma volume expanders)
  • Radiopaque contrast agents [1–3].

What is the treatment of drug-induced pruritus?

The cessation of the causative drug is an immediate priority [1,4–6]. Treatment depends on how the causative drug triggered the itching and its severity.

  • If the pruritus is associated with dry skin or secondary dermatitis, topical steroids and moisturisers may be of benefit.
  • Topical capsaicin has been reported as useful for treating localised drug-induced pruritus.
  • Oral antihistamines are effective if the pruritus is associated with an urticaria-like mechanism. 
  • Systemic corticosteroids may be effective if there is an inflammatory pathway suspected to be involved.
  • Naloxone or naltrexone is used for pruritus caused by the activation of mu receptor in the nervous system (in the case of opioids and plasma volume expanders).
  • Ursodeoxycholic acid and cholestyramine can reduce pruritus due to cholestatic liver injury.
  • Doxepin, amitriptyline, gabapentin, paroxetine, and ondansetron can also be used as second- or third-line antipruritic agents.
  • Phototherapy can also be of benefit.

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Related information

 

References

  1. Reich A, Ständer S, Szepietowski JC. Drug-induced pruritus: a review. Acta Derm Venereol 2009; 89: 236–44. DOI: 10.2340/00015555-0650. Journal
  2. Szepietowski JC, Reich A, Legat F. Cutaneous drugs reactions and drug-induced pruritus. In: Misery L, Ständer S (eds). Pruritus. London: Springer-Verlag, 2016: 169–82.
  3. Habif T. Exanthems and drug eruptions. In: Habif T. Clinical dermatology: a color guide to diagnosis and therapy, 6th edn. Philadelphia: Saunders, 2015: 562–76.
  4. Ebata T. Drug-induced itch management. Curr Probl Dermatol 2016; 50: 155–63. DOI: 10.1159/000446084. Journal
  5. Page EH. Itching — dermatologic disorders. MSD Manual Professional Version. Available at: www.msdmanuals.com/professional/dermatologic-disorders/approach-to-the-dermatologic-patient/itching (accessed 28 June 2018).
  6. Patel T, Yosipovitch G. Pruritus. In: Lacoutre ME (ed). Dermatologic principles and practice in oncology: conditions of the skin, hair, and nails in cancer patients. Hoboken, NJ: Wiley-Blackwell, 2014: 122–8.
  7. Sim DW, Park KH, Park HJ, et al. Clinical characteristics of adverse events associated with therapeutic monoclonal antibodies in Korea. Pharmacoepidemiol Drug Saf 2016; 25: 1279–86. DOI: 10.1002/pds.4049. PubMed

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