What are the next steps for a patient experiencing itchiness, dizziness, diarrhea, stomach pain, inability to stand, and weakness while taking Augmentin (amoxicillin/clavulanate) for sinusitis?

Discontinue Augmentin Immediately and Evaluate for Hypersensitivity Reaction

Stop the Augmentin now and assess the patient urgently for a potential allergic reaction, as the combination of itchiness, dizziness, weakness, and inability to stand raises concern for an evolving hypersensitivity reaction that could progress to anaphylaxis. 1

Immediate Assessment Required

Classify the Reaction Type

• Itchiness without rash can represent the early phase of a Type I hypersensitivity reaction, particularly when accompanied by systemic symptoms like dizziness and weakness 1
• Dizziness and inability to stand may indicate hypotension from an allergic reaction or severe dehydration from gastrointestinal losses 1
• Diarrhea and stomach pain are common adverse effects of Augmentin (occurring in 4-7% of patients), but when combined with systemic symptoms, require urgent evaluation 1, 2

Critical Decision Point: Is This Anaphylaxis?

Assess immediately for:

• Hypotension (systolic BP <90 mmHg or >30% decrease from baseline)
• Respiratory symptoms (wheezing, stridor, difficulty breathing)
• Progression of skin symptoms (urticaria, angioedema developing)
• Severe weakness preventing ambulation

If any of these are present, treat as anaphylaxis with intramuscular epinephrine 0.3-0.5 mg and call emergency services. 1

If Not Anaphylaxis: Manage Augmentin-Related Adverse Effects

Gastrointestinal Toxicity Management

• Diarrhea is the most common adverse effect of amoxicillin-clavulanate, occurring in 4-7% of patients, and is typically related to the clavulanate component 1, 2
• The FDA label explicitly warns that diarrhea can be severe and may require discontinuation of the antibiotic 1
• Assess for dehydration as the cause of dizziness and weakness—check orthostatic vital signs, mucous membranes, and skin turgor 1

Rule Out Clostridioides difficile Infection

• The FDA label warns that C. difficile-associated diarrhea can occur even 2 months after antibiotic use and presents with watery/bloody stools, stomach cramps, and fever 1
• If diarrhea is severe or lasts >2-3 days, test for C. difficile and consider empiric treatment if high suspicion 1

Alternative Antibiotic Selection

For Non-Anaphylactic Penicillin Allergy

Switch to a respiratory fluoroquinolone as the safest and most effective alternative:

• Levofloxacin 500 mg once daily for 10 days provides 90-92% clinical efficacy against resistant S. pneumoniae and β-lactamase-producing H. influenzae 3, 4
• Moxifloxacin 400 mg once daily for 10 days is an equivalent alternative 3, 4

If Mild/Delayed Reaction Only (Not Type I Hypersensitivity)

• Second-generation cephalosporins (cefuroxime 250-500 mg twice daily for 10 days) have negligible cross-reactivity risk with penicillins 3, 4
• Third-generation cephalosporins (cefpodoxime 200 mg twice daily or cefdinir 300 mg twice daily for 10 days) provide superior H. influenzae coverage 3, 4

Supportive Care and Monitoring

Immediate Interventions

• Discontinue Augmentin immediately—do not give another dose 1
• Provide oral or IV rehydration if orthostatic hypotension or clinical dehydration present 3
• Administer antihistamines (diphenhydramine 25-50 mg) if itching persists without progression to anaphylaxis 1

Adjunctive Therapies for Sinusitis

• Continue intranasal corticosteroids (mometasone or fluticasone twice daily) to reduce mucosal inflammation 5, 3
• Saline nasal irrigation provides symptomatic relief and improves drainage 5, 3
• Analgesics (acetaminophen or ibuprofen) for pain and fever 3

Follow-Up and Reassessment

Within 24-48 Hours

• Reassess symptom improvement on the new antibiotic—expect noticeable improvement within 3-5 days 3
• Monitor for resolution of GI symptoms after stopping Augmentin—diarrhea should improve within 24-48 hours 1
• If no improvement or worsening, consider alternative diagnosis (viral rhinosinusitis, complications, resistant organisms) 5, 3

Document the Reaction

• Record this as a penicillin/β-lactam allergy in the patient's chart to prevent future exposure 1
• Specify the reaction type (GI intolerance vs. possible hypersensitivity) to guide future antibiotic selection 3, 4

Critical Pitfalls to Avoid

• Never continue Augmentin when a patient reports itching with systemic symptoms—this may represent early anaphylaxis 1
• Do not assume all symptoms are GI side effects—the combination of itching, dizziness, and weakness requires urgent evaluation for hypersensitivity 1
• Avoid azithromycin or other macrolides as alternatives—resistance rates exceed 20-25% for sinusitis pathogens 3, 4
• Do not use clindamycin monotherapy—it lacks coverage for H. influenzae and M. catarrhalis 3, 4