What is the Dibucaine (Dibucaine hydrochloride) number?

From the FDA Drug Label

Dibucaine 1% Hemorrhoidal ointment The Dibucaine number is 1%, which refers to the concentration of Dibucaine in the hemorrhoidal ointment 1.

From the Research

Dibucaine Number

The Dibucaine number is a measure used to identify patients who are at risk of prolonged neuromuscular blockade due to atypical cholinesterase.

• It is defined as the percentage of enzyme activity inhibited by dibucaine hydrochloride [ 2, 3 ].
• A normal Dibucaine number is typically above 70 [ 4 ].
• Patients with a Dibucaine number below 30 are at higher risk of prolonged neuromuscular blockade [ 2 ].
• The incidence of Dibucaine numbers below 30 is approximately 1:1,400 [ 2 ].

Measurement of Dibucaine Number

• The Dibucaine number can be measured using automated analyzers such as the Hitachi 917-analyzer [ 2 ] or the Greiner G450 selective analyzer [ 3 ].
• The measurement involves determining the percentage of enzyme activity inhibited by dibucaine hydrochloride [ 3, 5 ].

Clinical Significance

• A low Dibucaine number is associated with an increased risk of prolonged neuromuscular blockade after administration of succinylcholine or mivacurium [ 2, 6 ].
• Routine measurement of the Dibucaine number can help identify patients at risk and avoid unnecessary administration of these drugs [ 2 ].