Some examples of drugs causing pruritus:
(1) opioid analgesics
(2) antibiotics
(3) antihypertensive drugs
(4) hormones
(5) targeted therapies
(6) anti-epileptic drugs
(7) antidepressants
(8) hydroxyethyl starch
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Temporal Classification
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Duration
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Pruritus
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acute
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often hours or days, up to 6 weeks
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often stops once the drug is stopped
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chronic
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more than 6 weeks
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may persist for some time after the drug is stopped
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Mechanisms for the pruritus:
(1) cholestatic jaundice
(2) allergy, including urticaria
(3) chemical release – serotonin, interleukin-2, leukotrienes, etc
(4) involvement of nerves
(5) skin lesions (rash, etc)
(6) xerosis
(7) unknown
Barriers to diagnosis:
(1) The possibility of the pruritus being caused by a drug not considered.
(2) The frequency of a pruritic reaction with the drug uncommon.
(3) The onset was delayed after starting the drug.
(4) The pruritis persisted for some time after the drug was stopped.
(5) The pruritis was ascribed to a different cause (such as the condition for which the patient is being treated).
(6) The patient is taking multiple drugs for multiple conditions.
(7) The patient denies drug use (like opiates).
(8) The patient cannot give a history.
