Anacaine

Benzocaine is a local anesthetic (LA) which is used topically to reduce pain or discomfort caused by minor skin irritations, stomatitis, sore throat, sunburn, vaginal or rectal irritation, painful ulcers of mouth and throat, hemorrhoids, and many other sources of minor pain on the body surface. 

According to chemical structure benzocaine belongs to ester group of local anesthetics. It causes reversible loss of sensory perception, especially of pain in a restricted area of the body. It blocks generation and conduction of nerve impulse at any part of the neuron with which it come in contact, without causing any structural damage. As a result no pain sensation takes place. 

This medicine is available as an over-the-counter medicine without a prescription; however, your doctor may give you special instructions to ensure the proper use and dosage schedule in order to improve your medical condition. This product is available in the following dosage forms: 

• Lozenges
• Spray
• Cream
• Ointment
• Dusting powder
• Suppository
• Gel/Jelly

If you are about to start a drug therapy, the risk-benefit ratio of taking the drug should be considered carefully. Here, the suitable drug therapy is chosen with active participation of both the doctor and the patient. 

There are some important factors such as drug interactions, metabolic impairment, hypersensitivity reaction, pregnancy, lactation etc. which may alter the desired therapeutic effects of such medications. 

Sometimes the presence of other health disorders affects the beneficial effects of this medicine and even may cause serious toxic effects. If you have had any allergic reactions to any medicine then you must inform your doctor about that. 

Make sure you mention your doctor if you have any other health problems or medical disorders, especially:

• Cardiovascular diseases (e.g. myocardial infarction, congestive heart failure, uncontrolled hypertension, cardiac arrhythmias etc.)
• Respiratory disorders (e.g. bronchial asthma, bronchitis, emphysema etc.)
• Metabolic impairments (e.g. diabetes mellitus, thyrotoxicosis)
• Hepatic and/or renal impairments

Moreover, certain drugs should not be used concurrently with such medications. It is always recommended to consult with your doctor if you are in need of some other medications or even any over-the-counter medicine for another health problem in order to avoid unwanted toxic effects. 

Besides, you should not use any vasoconstrictors like adrenaline while you are undergoing benzocaine therapy. Concurrent use of vasoconstrictors (e.g. adrenaline) prolongs the duration of action of benzocaine by decreasing its rate of removal from the local site, which increases the chances of subsequent local tissue edema and necrosis. 

In addition, it also delays wound healing by reducing oxygen supply and enhancing oxygen consumption in the affected area. Additionally, it may raise blood pressure and promote arrhythmia in susceptible individuals.

On the contrary, the clinically used local anesthetics (e.g. benzocaine) have minimal local irritant action. They also reduce release of acetylcholine from motor nerve endings. 

As a result, paralysis of the voluntary muscles supplied by that nerve may also occur but rarely. However, benzocaine fails to afford adequate pain control in inflamed tissues because of reasons:

• Blood flow to the inflamed area is increased, that’s why benzocaine or other local anesthetic is removed more rapidly from the site.
• Inflammation lowers the pH of the affected tissues which inactivate greater fraction of such medications as it is in the ionized form hindering diffusion into the axolemma. 
• Certain inflammatory products produced by the cells often oppose the anesthetic action of benzocaine.

You should use this medicine following the directions given by your doctor. The dosage schedule and the duration of drug therapy depend on the particular medical problem for which you are using this medicine. 

However, the therapeutic dose may vary with patient’s condition or requirement and the strength of the medicine as well. In order to treat ulcers, burns, and itching dermatoses; 1-2% benzocaine is preferably used by the physicians. 5% benzocaine is used over anal canal and rectum in order to treat fissure, painful piles as well as prior minor surgery and proctoscopy.

Further, it is advised to store the medicine in a closed container at room temperature away from heat, moisture, and direct light. All kinds of medicines should be kept out of the reach of children. However, outdated medicines should be disposed by an appropriate way.

Firstly, regular visits to your doctor are recommended to check that this medicine is working properly or not. It is advised to wash your hands with soap and water before and after using this medicine. You should not apply this medicine over the area of open wounds, burns, or inflamed skin. 

Further, you should stop using this medicine and check with your doctor immediately if you have:

• developed rashes
• stinging
• swelling or 
• irritation over the skin following application of such medications. 

In addition, this drug should be used cautiously in case of glucose-6-phosphodiesterase deficiency, methemoglobin reductase deficiency, and pyruvate-kinase deficiency. 

Moreover, the use of such medications is not suitable for those children who are under the age of 2 years.

There are some unwanted side-effects associated with each drug that usually do not need medical attention. These side-effects usually go away during the treatment episode as your body adjusts to the medicine. 

Your healthcare professional may advise you about the ways how to prevent or reduce those unwanted side-effects. Sometimes you may need to consult with the doctor if you feel any of the following toxic effects:

• Problems affecting central nervous system (CNS) are light-headedness, dizziness, sleepiness, auditory and visual disturbances, mental confusion, disorientation, shivering, involuntary movements, convulsions, CNS depression leading to respiratory arrest.
• Neurotoxicity (sensory and motor deficits) has been reported in certain individuals affecting peripheral nervous system. 
• Cardiovascular toxicity of benzocaine is manifested as myocardial depression, vasodilatation, bradycardia, hypotension, cardiac arrhythmias and vascular collapse.
• Methemoglobinemia may also take place which lowers the amount of oxygen in your blood stream excessively resulting in medical emergency.
• Hypersensitivity reactions like rashes, angioedema, dermatitis, contact sensitization, asthma, and rarely anaphylaxis may occur.
• Additionally, methylparaben is often added as a preservative in certain local anesthetic solutions which may cause serious allergic reactions.