Overview
Clemastine has been available in the market for several years. The drug has been approved by the Food and Drug Administration (FDA) for its safety and efficacy. The drug was first approved by the FDA in the year 1977 to relieve symptoms of allergic rhinitis, which include sneezing and runny nose. It is also approved to treat conjunctivitis and urticaria. The drug was approved after rigorous clinical trials, which included the assessment of the drug's safety profile and its effectiveness in treating targeted conditions.
How Does Clemastine Work?
It is an antihistamine that blocks the messengers responsible for inflammation and congestion. Histamine is a naturally occurring substance in the body that is responsible for allergies, itching, and sneezing. The drug binds to the H1 receptors on the cells, especially in the blood vessels, skin, and respiratory system. These blocked receptors prevent histamine from exerting its effects. Blocking histamine receptors is beneficial in reducing allergic reactions. Also, the drug has anticholinergic properties apart from antihistamine activities. So the overall action of the drug is to modulate the chemical pathways involved in allergic reactions and provide relief from symptoms.
Uses:
Most uses of the drugs are primarily directed at treating allergic conditions. Some uses of Clemastine are mentioned below:
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Allergic Rhinitis - The drug aids in relieving symptoms caused by this condition. The symptoms include sneezing, nasal congestion, itching, and runny nose. It blocks the actions of histamine, which is generally released during allergic reactions.
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Allergic Conjunctivitis - The drug reduces the symptoms like redness and itching of the eyes. It also helps to reduce the discomfort of the eye and prevents watering of the eyes.
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Urticaria - In urticaria, Clemastine blocks the symptoms of itching and swelling on the skin cells, thereby relieving the symptoms.
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Pruritis - The drug helps to prevent itching caused by this condition.
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Atopic Dermatitis - It is a chronic inflammatory condition of the skin, and the drug acts on the symptoms like redness and rashes and helps to treat them.
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Insect Bites - The drug helps to eliminate the discomfort caused by insect bites.
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Motion Sickness - The drug treats nausea, vomiting, and dizziness as it comprises anticholinergic effects. It blocks the vomiting reflex in the brain.
Dosage:
The drug is available in different forms to cater to the needs of every individual. A few examples of the common forms and dosages have been given below:
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Tablets - It is the most commonly available form and comes in various strengths ranging from one milligram to 2.5 milligrams. The frequency of medication depends on the underlying condition and the response of the individual to the drug.
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Syrup - The drug is available in the form of syrup for individuals who have difficulty swallowing tablets. The syrup dosage depends on the concentration of the medication and the age of the individual. In addition, it also depends on the weight of the individual, so taking the right amount of dosage is very crucial to obtain maximum benefits.
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Injection - The drug could be administered via injection in the hospital set up by a healthcare provider. It is usually administered in cases of severe allergic reactions, where oral administration is not an option.
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Extended-release Tablets - These tablets release Clemastine over a period of time and provide long-lasting effects, which potentially reduces the frequency of dosing. The drug should be taken as per the instructions of the healthcare professional.
Warnings:
The drug is considered the most safe and effective when used as directed by the healthcare professional. However, it is important to keep in mind that the drug has a few warnings and precautions to ensure the safety of the individual.
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The drug causes sedation and drowsiness, which impairs cognitive and motor functions. It has to be used cautiously while engaging in activities that require alertness, like driving. Also, it is important to avoid alcohol consumption as it intensifies drowsiness.
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In the central nervous system, it causes effects like dizziness, confusion, and blurred vision. If these symptoms occur recurrently, it is better to avoid the activities requiring mental alertness.
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Individuals with pre-existing medical conditions like asthma, liver and kidney diseases have to use the drug cautiously. Hence it is safer to inform the healthcare professional before starting the drug use.
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The safety of the drug during pregnancy and breastfeeding is not well established, and hence it is recommended to consult a healthcare professional.
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A few individuals could experience allergic reactions to the drug, which can be swelling and rashes. So in case of any such adverse reactions, it has to be quickly brought to the notice of healthcare professionals.
For Patients:-
What Is Allergic Rhinitis?
The condition is commonly known as hay fever, which affects the nose and sinuses. It usually occurs when the immune system overreacts to harmless substances in the environment, which are called allergens, and triggers an allergic response. The causes of the condition are primary exposure to pollen grains, dust particles, and certain foods. When the susceptible individual is in contact with the immune system, it releases various chemicals like histamine, which leads to inflammation. The most common symptoms of the condition are sneezing, runny nose, and postnasal drip. In addition, a few individuals could have watery eyes and itching in the throat. These symptoms can impact daily quality of life. The condition is classified into two types, namely,
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Seasonal allergic rhinitis.
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Perennial allergic rhinitis.
Seasonal allergic rhinitis occurs during a specific time of the year, whereas perennial allergic rhinitis occurs whenever the individual comes in contact with anything that triggers allergic reactions.
Learn More About Clemastine:
When and How Often to Take Clemastine?
Dosing of the drug depends on specific formulations and the strength of the medication. It is crucial to follow the instructions given by the health professional, and a few guidelines are given below:
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The drug can be consumed as tablets or syrup, and the recommended dose is usually one tablet or two teaspoons of syrup every 12 hours.
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For children over six to 12 years, the recommended dose is usually half the adult dose.
The dosage and frequency depend on the severity of symptoms, and it is recommended to consult a healthcare professional. The appropriate dosage is based on age and medical conditions. Exceeding the dosage can be life-threatening. Hence extreme care is required to handle the dosage,
How Effective Is Clemastine?
The drug is highly effective in treating various medical conditions, specifically in relieving symptoms of allergies. It blocks the histamine effects and relieves the allergic symptoms.
Things to Inform The Doctor Before They Prescribe Clemastine:
Before consuming the drug, it is important to reveal if there have been previous episodes of an allergic reaction, current medications, and drug history for better clarity.
Starting Clemastine:
How to Take Clemastine?
Before consuming the drug, it is important to be familiar with the dosage and timings for drug administration. For oral administration, the drug is consumed with a glass of water as instructed by the healthcare professional. The prescribed dosage may vary depending on the conditions, and hence it has to be taken promptly without overdosing the drug. Avoid crushing or chewing the drug. The drug has to be completely swallowed for better effects.
Things to Do After Starting Taking Clemastine:
Look Out for Side Effects:
A few side effects of the drug are described below:
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Drowsiness, which is caused due to the sedative effect of the drug.
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Dry mouth or xerostomia, which is due to anticholinergic effects. This can be treated by chewing sugar-free gums.
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Blurred vision is seen in a few individuals.
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Dizziness in standing or sitting position.
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Sometimes the drug could cause nausea, vomiting, and constipation.
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Difficulty in urination.
Dietary Alterations:
No specific dietary alterations are required unless specified by the healthcare professional. In addition, it is safer to keep away from anything that could trigger allergic reactions.
What Should Be Done When a Dose Is Missed?
In case of missing a dose, it is safer to consume it at the earliest possible time. However, if it is close to the next dose, then it can be skipped. Do not overdose unnecessarily, as it can cause serious adverse effects.
What Should Be Done to Treat Clemastine Overdose?
If an overdose occurs, call for immediate help and inform the healthcare professional. Do not induce vomiting, as it may cause additional complications. Overdose is a serious medical emergency, and prompt medical attention is required.
How to Store Clemastine?
The drug should be stored in the same packaging as received to avoid contamination. Constantly transferring the medications to other boxes can affect the effectiveness of the drug.
The drug has to be placed at room temperature and avoid exposure to extreme temperatures like moisture and sunlight. Keep the drug away from children. Also, consider using childproof containers to enhance safety. Check the expiration date regularly.
How to Handle Clemastine?
Before consuming the drug, wash the hands thoroughly to prevent the transfer of contaminants. Use clean hands or gloves to take the medicine. Follow the prescribed dosage as per the doctor’s instruction.
How to Dispose of Clemastine?
Check the packaging for any specific disposal instructions. Contact the local take-back programs to ensure the safe disposal of the drug.
Avoid Self-Medication:
Self-medication can be very harmful. Hence it is important to consume any drug as per the instructions given by the doctor to ensure safety and efficacy.
Staying On Clemastine:
Keep a reminder to stay on track or maintain a habit of consuming the drug every day at the same time.
For Doctors:
Drug Taxonomy:
Drug Class - Antihistamine.
Chemical Structure - Alkylphenylketones.
Chemical Formula - C21 H26 CHINO.
Indication:
The drug treats medical conditions like allergic rhinitis, allergic conjunctivitis, and motion sickness.
Pharmacology:
Mechanism of Action:
Clemastine is a first-generation antihistamine that blocks the H1 receptor and acts as a competitive antagonist which effectively binds to the histamine receptor.
Pharmacodynamics:
The pharmacodynamics of the drug include competitive agonists at the H1 receptors, and anticholinergic effects, by blocking the neurotransmitter acetylcholine. In addition, it has sedative properties which can cross the blood-brain barrier and cause depression in the central nervous system.
Ingredients:
Active Ingredient: Clemastine fumarate.
Inactive Ingredients:
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Cellulose derivatives.
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Lactose.
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Magnesium stearate.
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Polyethylene glycol.
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Titanium dioxide.
Absorption:
After oral administration, the drug is rapidly absorbed into the gastrointestinal tract and is distributed to the bloodstream. The onset of action could vary between two to four hours. However, it may take some time to reach the peak value as it is influenced by various factors.
Distribution:
After absorption into the bloodstream, the drug readily crosses the brain barrier and is distributed to the central nervous system. It is later distributed to various organs in the body.
Metabolism:
It goes through extensive metabolism in the liver by P450 and forms the main metabolite in N-demethylation.
Elimination:
The excretion of the drug is via renal excretion. However, a small portion remains unchanged and is eliminated in the urine. The half-life of the drug may vary from eight to 21 hours.
Toxicity:
Exceeding therapeutic doses could have serious side effects on health. It results in drowsiness and urinary retention.
Clinical Studies for Clemastine :
Several clinical studies have been conducted to evaluate the drug’s efficacy. In a study conducted for allergic rhinitis, it was proved to treat the condition by reducing the symptoms effectively. Also, another study to treat urticaria proved the drug’s efficacy in reducing itching and improving skin lesions.
Drug Interactions:
Clemastine interacts with the following drugs:
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Monoamine oxidase inhibitors.
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Anticholinergic drugs.
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Ketoconazole.
Other Specifications:
Clemastine in Pregnant Women:
The exact use of the drug in pregnancy is yet to be established. So the drug is safely avoided unless recommended.
Clemastine in Lactating Women:
Very limited information is available about the use of drugs in lactating women. It is recommended to exercise caution during administration. The drug has the potential to pass breast milk; hence it is not recommended in feeding mothers as it could have potential risks to the child.
Clemastine in Pediatric Patients:
The drug is safe to use in pediatric patients as long as the exact dose per the patient’s requirements is administered.
Clemastine in Geriatric Patients:
The drug has to be handled with caution in pediatric patients as it could react with other medications. Also, elderly individuals have various health complications, so extra care could be required to monitor for any adverse symptoms. The drug is known to cause drowsiness and dizziness, which may increase the risk of falls in elderly individuals.
Clemastine in Renal Impairment Patients:
Dosage alterations are required in renal-impaired patients as they may affect kidney functions. This is because kidney functions could slow the clearance of the drug.
Clemastine in Hepatic Impairment Patients:
The drug has to be used carefully in patients with hepatic impairment. Very limited use of the drug has been established.
