How do you administer benzocaine (local anesthetic)/menthol lozenges?

From the Guidelines

To administer benzocaine/menthol lozenges, allow one lozenge to dissolve slowly in your mouth when needed for sore throat or mouth pain, but be aware of the potential risk of methemoglobinemia, a life-threatening adverse event associated with benzocaine use, as reported in a study published in Gastroenterology 1. When using these lozenges, it is essential to follow the recommended dosage and administration guidelines to minimize the risk of adverse events.

• Typically, you can use one lozenge every 2 hours as needed, but don't exceed more than 10 lozenges in a 24-hour period.
• Do not chew or swallow the lozenge whole, as this can increase the risk of methemoglobinemia.
• The lozenges work through two active ingredients: benzocaine, which is a local anesthetic that numbs the area, and menthol, which provides a cooling sensation that helps relieve discomfort.
• Before using, check the package for specific dosing instructions as concentrations may vary between products.
• If you have persistent throat pain lasting more than 2 days, develop fever, rash, or irritation, or if swallowing becomes difficult, discontinue use and consult a healthcare provider, as these symptoms may indicate a more serious condition that requires medical attention.
• These lozenges are not recommended for children under 5 years old, and you should avoid eating or drinking for 15 minutes after using them to allow the medication to work effectively. It is crucial to be aware of the signs and symptoms of methemoglobinemia, such as cyanosis despite adequate supplemental oxygen delivery, and to seek medical attention immediately if you experience any of these symptoms, as treatment with intravenous methylene blue may be necessary, as described in the study published in Gastroenterology 1.

From the Research

Administration of Benzocaine/Menthol Lozenges

To administer benzocaine (local anesthetic)/menthol lozenges, the following steps can be considered:

• Suck the lozenge slowly in the mouth, allowing it to dissolve and release the active ingredients [ 2 ].
• The lozenge should be allowed to dissolve completely in the mouth, providing longer contact time of the drug with the naso-pharyngeal mucosa [ 3 ].
• It is essential to follow the recommended dosage and administration instructions to minimize the risk of adverse events, such as methemoglobinemia [ 4, 5 ].

Important Considerations

• Benzocaine lozenges can be effective in reducing painful pharyngeal discomfort, with significant decreases in pain intensity compared to placebo [ 2 ].
• The use of benzocaine lozenges may be associated with a risk of methemoglobinemia, a condition characterized by abnormal levels of oxidized hemoglobin [ 4, 5 ].
• Health professionals should be aware of the potential risks and benefits of benzocaine lozenges and monitor patients for any adverse events [ 4 ].

Bioequivalence and In Vitro Testing

• The bioequivalence of locally acting lozenges can be evaluated using in vivo parameters, such as sucking times, saliva osmolality, and salivary flow rates [ 6 ].
• In vitro test methods, such as dissolution testing, can be used to predict the bioequivalence of lozenges, but may not accurately reflect in vivo conditions [ 6 ].