is an effective antihistamine that can quickly reduce allergy
symptoms within 24 hours. Though there are a number of precautions and side effects to watch out for.
Clemastinum is an antihistamine medicament having sedative and anticholinergic effects. It is used for the treatment of allergy symptoms including runny nose
, itchy skin, hives
, rash, sneezing
, red and teary eyes and pruritus
. It is also known as meclastin
and is classified as an antipruritic. Clemastinum is able to increase capillary dilatation and permeability as well as improve gastrointestinal and respiratory smooth muscle
Depending on the dosage taken, Clemastinum can cause paradoxical effects like CNS depression
and stimulation. By blocking the effects of natural-occurring histamine, it inhibits histamine's vasodilator and vasoconstrictor effects. The medicament comes in tablets and extended-release tablets, which should be taken orally. It is also available as a syrup by the brand name Tavist
Clemastinum can cause many side effects like drowsiness, xerostomia, nose
or throat, dizziness
, chest congestion, headache
, upset stomach
, excitability, nervousness, pupil dilation, extra sunlight sensitivity, heart
palpitation, sleepiness, enlarged prostate
and difficulty urinating. These symptoms should be reported to the doctor especially if they become severe. Other adverse reactions include loss of appetite
, vision changes and irritability. Some symptoms are mild and will only be present as the body adjusts to the medicament. Serious side effects like breathing difficulty, arrhythmia and ear
ringing should be taken care of immediately.
Patients with known hypersensitivity reactions to the medicament should never take it. Those with a history of lung
, ulcers, difficulty urinating, enlarged prostate
, overactive thyroid, hypertension
, seizure and heart disease should consult their doctor first before consumption. Breastfeeding mothers and pregnant women should ask their doctor first and elderly patients may require lower dosages since they are more sensitive to the medicament. Clemastinum can also interact with medicaments like MAOIs or monoamine oxidase inihibitors, sedatives, tranquilizers, narcotics and antipsychotics.
Clemastinum acts by aggressively binding to H1-receptor sites making it a selective histamine H1 antagonist. The sites are then blocked, stopping endogenous histamine from attaching. When endogenous histamine is blocked, it cannot act and cause symptoms and reactions. As a result, the patient experiences temporary relief. The medicament is thought to be metabolized in the liver
by mono-didemethylation and glucuronide conjugation.
12 patients suffering from anaphylactic reactions were given 1 mg of Clemastinum 4 times a day for 3 days. Within the first 24 hours, all patients had reduced symptoms and were completely free of symptoms by the second day. The only drawback was that 10 of the patients reported sleepiness that lasted up to 1 week after treatment was over.
Clemastinum is an over-the-counter or OTC medicament so a prescription is no longer needed. It is available in almost all pharmacies and doctors' clinics. Check the expiration date and manufacturer upon purchase to ensure quality and freshness. The medicament may also be ordered online at certified pharmacies.
Drowsiness is one of the most common side effects of Clemastinum so patients should not drive or operate heavy machinery until full effects are realized. Children younger than 12 years old should ask a doctor first to ensure safety. The medicament should be stored at room temperature away from sunlight and moisture. Dosage should also be followed religiously and patients should never take more or less than recommended.
Clemastinum has the following structural formula:
• Molecular formula of clemastinum is C21H26ClNO
• Chemical IUPAC Name is 2-[2-[1-(4-chlorophenyl)-1-phenyl-ethoxy]ethyl]-1-methyl-pyrrolidine
• Molecular weight is 343.89 g/mol
• Clemastinum available : 1mg tablets