What medications should be prescribed for an adult patient with hypomania and chronic pruritus, assuming no contraindications?

Medication Management for Hypomania with Chronic Pruritus

For a patient with hypomania and chronic pruritus, prescribe fexofenadine 180 mg daily for the pruritus while avoiding sedating antihistamines and mood-destabilizing antidepressants, and coordinate with psychiatry for mood stabilizer management of the hypomania. 1

Treatment Algorithm for Chronic Pruritus in Bipolar Disorder

First-Line Approach: Non-Sedating Antihistamines

• Start with fexofenadine 180 mg daily as the foundation for pruritus management, as recommended by the British Association of Dermatologists for generalized pruritus of unknown origin. 1
• Fexofenadine is nonsedating, making it safer for long-term use and less likely to interfere with mood stability compared to first-generation antihistamines. 1
• Combine with emollients and self-care measures (keeping nails short, maintaining skin hydration) from the outset. 2, 1

Critical Medications to AVOID in Hypomania

• Do not use sedating antihistamines (diphenhydramine, promethazine) except in short-term or palliative settings, as long-term use may predispose to dementia and can worsen mood instability. 1
• Avoid antidepressants that can trigger mania: While paroxetine, fluvoxamine, sertraline, and mirtazapine are effective for chronic pruritus 1, 3, these agents carry significant risk of precipitating manic episodes in patients with bipolar disorder and should only be used with concurrent mood stabilizer coverage and psychiatric consultation.
• Doxepin (both topical and systemic) should be avoided despite its antipruritic properties, as it is a tricyclic antidepressant that can destabilize mood. 1

Second-Line Options Safe in Hypomania

If fexofenadine proves ineffective after adequate trial:

• Gabapentin or pregabalin are preferred second-line agents as they have antipruritic efficacy without mood-destabilizing effects. 1, 4
• Naltrexone (opioid antagonist) can be considered for pruritus without significant psychiatric contraindications. 1
• Ondansetron or aprepitant (5-HT3 antagonists) may be tried, though evidence for non-opioid-induced pruritus is limited. 1

Specific Considerations Based on Pruritus Etiology

If cholestatic pruritus is identified:

• Rifampicin 150 mg twice daily is first-line treatment, with monitoring for hepatotoxicity. 5
• Avoid gabapentin specifically in hepatic pruritus as it is ineffective in this context. 5

If inflammatory pruritus (eczema, psoriasis):

• Topical corticosteroids (hydrocortisone 2.5% or triamcinolone 0.1%) or tacrolimus ointment are appropriate first-line treatments. 4
• Approximately 60% of chronic pruritus cases are inflammatory in origin. 4

If neuropathic pruritus:

• Topical menthol, pramoxine, or lidocaine can be used safely. 4
• Gabapentin is particularly effective for neuropathic pruritus (postherpetic neuralgia, notalgia paresthetica). 4

Psychosocial Interventions

• Refer to psychiatry for mood stabilizer optimization and to address the hypomania directly. 2
• Consider referral to clinical psychology for behavioral interventions including habit reversal training, cognitive restructuring, and relaxation techniques, which can be beneficial for chronic pruritus without medication interactions. 2
• Significant psychosocial morbidity including anxiety and depression develops in up to one-third of individuals with chronic pruritus, requiring integrated psychiatric care. 2

Common Pitfalls to Avoid

• Never assume pruritus is purely psychogenic in psychiatric patients—always investigate for physical causes including dermatological, systemic (renal, hepatic, thyroid), and medication-induced etiologies. 2
• Do not use high-dose antihistamine combinations (multiple agents together) as monotherapy with high-dose desloratadine 20 mg daily appears more effective than combinations. 6
• Avoid prescribing antidepressants for pruritus without concurrent mood stabilizer coverage and psychiatric consultation in bipolar patients. 3
• Remember that antihistamines have limited effectiveness for non-histamine-mediated pruritus, which represents the majority of chronic pruritus cases. 1

Monitoring and Escalation

• If fexofenadine fails after 2-4 weeks, consider phototherapy (NB-UVB) which is highly effective for many types of chronic pruritus before adding multiple systemic agents. 1
• For refractory cases, dermatology referral for consideration of dupilumab or methotrexate may be appropriate, though approximately 10% of patients do not respond to topical therapies. 4