Can Ceftazidime Cause Drowsiness in Elderly Patients?
Yes, ceftazidime can cause drowsiness and altered mental status in elderly patients, particularly those with renal impairment, through a neurotoxic mechanism that manifests as confusion, disorientation, and decreased level of consciousness.
Mechanism and Clinical Presentation
Ceftazidime-induced neurotoxicity presents with a characteristic pattern of neurological symptoms in at-risk populations:
- Confusion with temporal-spatial disorientation occurs in 96% of affected patients 1
- Drowsiness and decreased alertness are common manifestations, often progressing to frank confusion 2
- Myoclonus develops in 33% of cases, and seizures occur in 13% 1
- The neurotoxicity typically manifests subacutely, with a median interval of 3 days between symptom onset and diagnosis 1
High-Risk Patient Populations
Elderly patients face substantially elevated risk, especially when combined with other factors:
- Elderly patients with chronic kidney disease (stage 4 or higher) or acute kidney injury are at highest risk 2
- Renal insufficiency allows accumulation of ceftazidime to potentially toxic levels since the drug is predominantly excreted renally 3
- Patients over 77 years old with end-stage kidney disease requiring hemodialysis represent the highest-risk category 2
- Liver dysfunction serves as an additional risk factor by increasing blood-brain barrier permeability 3
Diagnostic Approach
When an elderly patient on ceftazidime develops drowsiness or confusion:
- Suspect ceftazidime neurotoxicity immediately if the patient has renal impairment and develops altered mental status 3-13 days after starting therapy 2, 1
- Obtain EEG if available—generalized periodic discharges with triphasic wave patterns suggest drug-induced encephalopathy 3
- Rule out other causes (hepatic encephalopathy, intracranial pathology, metabolic derangements), but do not delay ceftazidime discontinuation while awaiting results 3
- Check ammonia levels and head CT to exclude alternative diagnoses 3
Management
- Discontinue ceftazidime immediately upon suspicion of neurotoxicity 2, 1
- Symptom improvement typically occurs within 8 days of drug discontinuation, with complete remission expected 2
- The dramatic improvement following ceftazidime cessation confirms the diagnosis retrospectively 3
Critical Pitfall to Avoid
The median time to diagnosis is 3 days, but delayed recognition is common because confusion and drowsiness in elderly uremic patients may be attributed to other causes 1. Clinicians must maintain high suspicion for ceftazidime neurotoxicity in any elderly patient with renal dysfunction who develops new or worsening mental status changes while receiving this antibiotic, rather than assuming the symptoms result from the underlying infection or comorbidities.