Tavist® is often the US brand name for a generic medicine called clemastine, which may be sold over the counter or prescribed in different formulations. There are certainly other brand names for clemastine, but Tavist® may be the most recognizable, at least in the US. This drug is an antihistamine that is usually recommended to treat seasonal allergies or occasional bouts of allergy. It might also be suggested for conditions like hives or other allergic skin itching.
As with most antihistamines, Tavist® helps to block histamine response. When allergens are present this may be useful in dulling the body's reaction to them. Given an allergic response, clemastine could alleviate symptoms or keep some symptoms from emerging. Most often it can help with seasonal allergic rhinitis symptoms that include stuffy or runny nose and itchy eyes. It is usually not considered appropriate for allergic symptoms that include asthma or bronchitis because it may cause thickening of secretions that worsen these conditions.
Many of the antihistamines produced today are marketed as being non-drowsy, and Tavist® is not one of these medications. It can cause slight to severe drowsiness. Some suggest it is less likely to result in the severe drowsiness that happens when people use diphenhydramine (Benadryl®), but still may impair function to a certain degree. The degree to which this is bothersome is dependent on the individual, but people using the medicine for the first time should probably not drive or operate machinery until they determine its effects.
Many people use Tavist® with few or negligible side effects. Drowsiness is certainly a potential result. Some people have dry mouth or headache. People who have prostate difficulties may experience increase in urination difficulty and long time use might further enlarge the prostate gland.
There are more serious and rarer side effects that may result when people use Tavist®. These include a risk of developing tardive dyskinesia (involuntary movements of body), having serious increase in asthma, or having convulsions. Some people will feel a rapid heartbeat, palpitations, extreme dizziness, tightness of the chest of very low blood pressure. Allergic reactions to clemastine occur and symptoms of rash, itchiness, swelling of the face, tongue or lips, wheezing and general difficulty breathing are possible reactions. Any of these side effects require immediate medical attention, though it should be restated occurrence level is low.
Like many drugs, clemastine interacts with other drugs/substances. Drugs with sedating qualities like benzodiazepines or opiate pain relievers could intensify drowsiness. Combining alcohol and antihistamines is not advised for this reason, too. People should not take Tavist® with monoamine oxidase inhibitors (MAOIs), and should discuss the risk versus benefits of using clemastine with other antidepressants or psychiatric medications.
Conditions adversely affected by clemastine include asthma, hyperthyroidism, high blood pressure, heart disease in general, glaucoma, present problems with prostate or urinary tract, and ulcers. Other conditions might also be affected by Tavist®. To make sure this medication is safe and appropriate, people are advised to seek counsel from their physicians prior to obtaining it.