Does ketamine increase intraocular pressure?

Effect of Ketamine on Intraocular Pressure

Ketamine can increase intraocular pressure (IOP), as stated in the FDA drug label, and should be used with caution in patients with glaucoma or at risk for elevated IOP. 1

Evidence on Ketamine and IOP

The FDA drug label for ketamine explicitly lists "elevation in intraocular pressure" as an adverse reaction in the eye disorders category 1. This represents the highest level of evidence regarding ketamine's effects on IOP.

Mechanism and Clinical Implications

Ketamine's sympathomimetic effects may contribute to IOP elevation through:

• Increased central venous pressure
• Stimulation of the sympathetic nervous system
• Increased aqueous humor production

Patient-Specific Considerations

High-Risk Populations

Ketamine should be avoided or used with extreme caution in:

• Patients with glaucoma
• Patients with ocular trauma
• Patients undergoing intraocular surgery
• Patients with elevated baseline IOP

The FDA label specifically states that ketamine is "contraindicated in patients at risk of increased intraocular pressure (glaucoma)" 1.

Clinical Context Matters

The magnitude of IOP elevation appears to be:

• Dose-dependent (higher doses = greater IOP increase)
• More significant with IV administration
• Potentially transient (peaks within 5-10 minutes after administration)

Research Findings

Recent pediatric studies have shown conflicting results:

• Some research suggests minimal clinically significant IOP elevation with standard procedural sedation doses 2, 3
• However, these studies were conducted in patients without pre-existing ocular conditions

Animal studies have demonstrated more consistent IOP increases:

• In dogs, ketamine at 5 mg/kg IV caused significant IOP elevation 4
• In cats, ketamine did not significantly increase IOP compared to baseline 5

Practical Recommendations

1. For patients with known glaucoma or elevated IOP:

   • Consider alternative sedative/analgesic agents
   • If ketamine must be used, monitor IOP closely
   • Use the lowest effective dose

2. For patients undergoing eye procedures:

   • Avoid ketamine if the procedure involves open globe injuries
   • Consider alternative agents for intraocular surgery

3. For patients requiring procedural sedation:

   • In patients without ocular risk factors, ketamine can be used at standard doses
   • Lower doses (≤3 mg/kg) may have minimal effect on IOP 6

Monitoring Recommendations

When ketamine must be used in patients with ocular concerns:

• Measure baseline IOP when possible
• Monitor IOP during and after administration
• Be prepared to treat elevated IOP if it occurs
• Consider ophthalmology consultation for high-risk cases

Alternative Agents

For patients where ketamine is contraindicated due to IOP concerns:

• Propofol (though caution in hemodynamically unstable patients)
• Etomidate (minimal effects on cardiovascular regulation)
• Benzodiazepines (with appropriate airway monitoring)

Remember that the risk of increased IOP must be weighed against ketamine's beneficial properties, including maintenance of respiratory drive and protective airway reflexes, especially in emergency situations.