Usage
Lidocaine + Phenazone ear drops are prescribed for the symptomatic relief of ear pain and inflammation associated with acute otitis media (middle ear infection), especially in the congestive and serous stages. It can also be used to facilitate ear wax removal. It falls under the pharmacological classifications of:
- Local anesthetic: Lidocaine
- Analgesic: Phenazone
- Anti-inflammatory: Phenazone
Lidocaine blocks sodium channels in nerve cell membranes, inhibiting pain signal transmission. Phenazone reduces inflammation and pain by inhibiting prostaglandin synthesis.
Alternate Names
This combination is often referred to as “Lidocaine and Phenazone ear drops”. There are also different international brand names such as Otigo, Oticaine, and Otogon. Lidocaine is sometimes referred to as lignocaine. Lidozone is another brand name used for this medication.
How It Works
Pharmacodynamics: Lidocaine acts locally by blocking voltage-gated sodium channels, preventing nerve impulse conduction and thus producing anesthesia. Phenazone acts as an analgesic and anti-inflammatory agent, likely by inhibiting cyclooxygenase and reducing prostaglandin synthesis. The combination’s synergistic action provides more intense and longer-lasting pain relief than either drug alone.
Pharmacokinetics: When administered as ear drops, with an intact eardrum, systemic absorption is minimal. If the eardrum is perforated, systemic absorption can occur. Lidocaine is primarily metabolized in the liver, with less than 10% excreted unchanged in urine. Its elimination half-life is approximately 12 hours. Phenazone is metabolized in the liver, and metabolites are excreted in urine, with a small amount eliminated via bile.
Mode of Action: Lidocaine binds to the intracellular portion of voltage-gated sodium channels, stabilizing the inactive state and preventing depolarization. Phenazone’s mechanism as an analgesic and anti-inflammatory agent is thought to involve cyclooxygenase inhibition, although the precise mechanism is not fully elucidated.
Receptor Binding, Enzyme Inhibition, or Neurotransmitter Modulation: Lidocaine primarily interacts with voltage-gated sodium channels. Phenazone’s action is primarily related to the inhibition of the cyclooxygenase enzymes involved in prostaglandin synthesis.
Elimination Pathways: Primarily hepatic metabolism for both drugs, with urinary excretion of metabolites. A small amount of phenazone might be excreted in bile.
Dosage
Standard Dosage
Adults:
The typical adult dose is 4 drops instilled into the affected ear canal 2 to 3 times daily.
Children:
The typical pediatric dosage is the same as for adults: 4 drops instilled into the affected ear 2-3 times a day.
Special Cases:
- Elderly Patients: No specific dosage adjustment is typically required.
- Patients with Renal Impairment: Dosage adjustments are not typically necessary due to minimal systemic absorption.
- Patients with Hepatic Dysfunction: Dosage adjustments are not typically necessary due to minimal systemic absorption.
- Patients with Comorbid Conditions: Monitor patients with certain conditions (e.g., G6PD deficiency) for potential complications, though dosage adjustment is not usually needed.
Clinical Use Cases
The combination is indicated specifically for acute otitis media; otitis as a complication after the flu; and barotraumatic otitis. It is primarily intended for outpatient use.
Dosage Adjustments
Dosage adjustment is not generally required for special populations. However, caution should be used in children, elderly and patients with existing renal or hepatic issues.
Side Effects
Common Side Effects
Itching, mild burning or stinging sensation, redness or swelling in the ear.
Rare but Serious Side Effects
Allergic reactions (e.g., rash, hives, itching, swelling).
Long-Term Effects
Not applicable, as the medication is intended for short-term use.
Adverse Drug Reactions (ADR)
Severe local reactions (e.g., blistering, peeling, or bleeding skin), dizziness, hearing changes.
Contraindications
Hypersensitivity to lidocaine, phenazone, or any component of the formulation. Perforated eardrum (tympanic membrane perforation).
Drug Interactions
Clinically significant drug interactions with Lidocaine + Phenazone ear drops are unlikely due to limited systemic absorption. However, caution should be exercised when used concomitantly with other local anesthetics or ototoxic medications. Concurrent use with other drugs that prolong the QT interval should be monitored carefully. Interactions with oral anticoagulants, antihypertensives, and antidepressants are not expected.
Pregnancy and Breastfeeding
The safety of using Lidocaine + Phenazone ear drops during pregnancy and breastfeeding has not been fully established. Use only if clearly needed and under the supervision of a physician.
Drug Profile Summary
Mechanism of Action: Lidocaine: blocks sodium channels. Phenazone: inhibits prostaglandin synthesis.
Side Effects: Itching, burning sensation, redness or swelling in the ear.
Contraindications: Hypersensitivity, perforated eardrum.
Drug Interactions: Unlikely due to minimal systemic absorption; caution with other local anesthetics and ototoxic drugs, drugs that prolong QT interval, monitor use with other sodium channel blockers and CYP3A4 inhibitors and inducers.
Pregnancy & Breastfeeding: Use with caution if clearly needed, safety not fully established.
Dosage: 4 drops in the affected ear, 2-3 times daily, for up to 7-10 days.
Monitoring Parameters: Resolution of ear pain and inflammation, monitoring for local or systemic side effects.
Popular Combinations
Lidocaine and Phenazone are typically not combined with other drugs in ear drop formulations.
Precautions
Confirm the integrity of the tympanic membrane before administration. Avoid contact of the dropper tip with the ear to prevent contamination. Discontinue use if symptoms worsen or do not improve within 7 days. Exercise caution in patients with a history of allergic reactions to local anesthetics. Limit treatment to 10 days.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Lidocaine + Phenazone ear drops?
A: The usual dose for both adults and children is 4 drops in the affected ear 2 to 3 times a day, for up to 7 or 10 days, as directed by a physician.
Q2: Can I use these ear drops if I have a perforated eardrum?
A: No, it is contraindicated in patients with a perforated eardrum. Systemic absorption can occur if the eardrum is perforated, leading to a greater risk of systemic side effects.
Q3: How long can I use Lidocaine + Phenazone ear drops?
A: Treatment should generally not exceed 7 to 10 days. If symptoms persist beyond this period, consult a physician for re-evaluation.
Q4: What should I do if I experience side effects?
A: Discontinue use and consult a physician. Mild side effects like itching or burning are usually transient. Severe or persistent side effects warrant immediate medical attention.
Q5: Can these ear drops be used in children?
A: Yes, the dosage for children is generally the same as for adults.
Q6: Can I use these drops while pregnant or breastfeeding?
A: The safety in pregnancy and breastfeeding hasn’t been fully established. Use only if clearly needed and after consulting a physician.
Q7: How does this combination work to relieve ear pain?
A: Lidocaine provides local anesthesia, and Phenazone reduces pain and inflammation. Their combined action offers enhanced pain relief.
Q8: What are the primary contraindications for this medication?
A: Known hypersensitivity to lidocaine, phenazone, or any of the excipients, and a perforated eardrum.
Q9: Can I use other ear drops concurrently with Lidocaine + Phenazone?
A: Consult a physician before using other ear drops concomitantly to avoid potential drug interactions or adverse effects.
Q10. What should I do if I miss a dose?
A: Administer the missed dose as soon as you remember. However, if it’s almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Don’t double the dose to catch up.
