What are the considerations for using Pheniramine (an antihistamine) in a hemodialysis patient with end-stage renal disease (ESRD) and comorbidities such as hypertension, diabetes, and cardiovascular disease, who is experiencing chills?

Pheniramine Use for Chills in Hemodialysis Patients

Pheniramine (an antihistamine) should generally be avoided in hemodialysis patients experiencing chills, as chills during dialysis are a high-risk symptom requiring investigation for infection rather than symptomatic suppression, and antihistamines pose specific risks in this population including central nervous system depression and potential masking of fever.

Understanding Chills in Hemodialysis: A Critical Warning Sign

Chills during hemodialysis represent a potentially serious complication that demands immediate clinical attention rather than symptomatic treatment. The evidence demonstrates that hemodialysis patients presenting with chills have remarkably high infection rates:

• 60% of hemodialysis patients with chills have a documented infection 1
• 33.5% have bacteremia specifically 1
• Patients with vascular catheters as dialysis access have 6-fold increased risk of bacteremia (OR 6.2) compared to those with fistulas or grafts 1

Why Antihistamines Are Problematic in Dialysis Patients

Antihistamines like pheniramine are specifically identified as central nervous system depressants that can cause medication-related adverse events during dialysis sessions:

• Antihistamines can cause altered mental status or falls while patients are at the dialysis unit 2
• These medications may complicate the clinical picture by masking fever or other signs of infection 2
• The medication reconciliation literature emphasizes that CNS depressants (including antihistamines) are high-risk medications in dialysis patients 2

Appropriate Clinical Approach to Chills During Dialysis

Instead of treating chills symptomatically with antihistamines, implement this evidence-based algorithm:

Immediate Assessment Required:

• Check temperature immediately - fever is a significant risk factor for bacteremia (OR 1.6) 1
• Evaluate dialysis access type - catheter access dramatically increases infection risk 1
• Obtain complete blood count - leukocytosis is an independent risk factor for infection (OR 1.265) 1
• Check serum albumin - hypoalbuminemia increases infection risk 1
• Identify obvious infection sources - respiratory, urinary, access site 1

Risk Stratification for Antibiotic Decision:

Low-risk patients (may defer immediate antibiotics):

• Fistula or graft access (not catheter) 1
• No fever 1
• Normal white blood cell count 1
• Normal albumin 1
• No obvious infection source 1
• Only 6% of these patients have bacteremia 1

High-risk patients (require immediate antibiotics):

• All other patients should receive broad-spectrum antibiotic coverage immediately following a chills episode 1
• This includes anyone with catheter access, fever, leukocytosis, hypoalbuminemia, or obvious infection source 1

Alternative Management of Dialysis-Related Temperature Symptoms

If chills are related to dialysis temperature rather than infection, address the root cause:

• Isothermic dialysis (maintaining predialysis body temperature) reduces intradialytic morbid events by 25% 2
• Low-temperature dialysate (below core body temperature) decreases symptomatic hypotension and improves vascular reactivity 2
• Temperature modeling prevents rigors and shivering without medication 2

Critical Pitfalls to Avoid

Do not use pheniramine or other antihistamines to suppress chills in dialysis patients because:

1. Chills are a critical diagnostic sign - 60% indicate infection requiring antibiotics, not symptomatic suppression 1
2. Antihistamines mask fever - eliminating a key risk stratification parameter 1
3. CNS depression is high-risk - increases fall risk and altered mental status during dialysis 2
4. No renal dose adjustment data - pheniramine lacks specific dosing guidance for ESRD 3

Medication Safety Considerations in ESRD

The broader context of medication management in dialysis patients emphasizes:

• Structured medication reconciliation programs reduce hospitalizations and readmissions when pharmacists identify and resolve medication-related issues 2
• Medication review should occur frequently, as dialysis patients experience medication-related problems that disrupt treatments 2
• CNS depressants require particular caution in this population 2

When Antihistamines Might Be Considered (Rare Scenarios)

The only scenario where antihistamine use might be appropriate:

• Documented allergic reaction during dialysis (urticaria, pruritus without infection) 2
• After infection has been ruled out with appropriate workup 1
• Uraemic pruritus as a chronic issue (not acute chills) - though topical capsaicin is preferred over systemic antihistamines 2

Even in these cases, pheniramine is not the optimal choice - if an antihistamine is truly needed, select one with established safety data in renal failure and known dialyzability 2.