Leader Allerhist Side Effects
Generic Name: clemastine
Note: This page contains information about the side effects of clemastine. Some of the dosage forms included on this document may not apply to the brand name Leader Allerhist.
For the Consumer
Applies to clemastine: oral oral solution, oral tablets
Side effects include:
Sedation, sleepiness, dizziness, disturbed coordination, epigastric distress, thickening of bronchial secretions.
For Healthcare Professionals
Applies to clemastine: compounding powder, oral syrup, oral tablet
Nervous system side effects have included central nervous system depression which has commonly resulted in drowsiness, dizziness, and headache. Dyskinesias have rarely been reported following chronic use of antihistamines.[Ref]
Nearly all patients experience drowsiness. This drowsiness may subside in some patients with extended use. Patients should be warned against driving, as well as concomitant ingestion with alcohol and other sedative-hypnotic drugs.
Few cases of dyskinesias and tremors, often of the face, have been reported in patients whose chronic use of antihistamines extended over a period of 3 to 10 years. Some of these cases were only partially relieved by discontinuation of the drug. Haloperidol was successful in relieving symptoms.[Ref]
Gastrointestinal side effects have included dry mouth and constipation due to anticholinergic effects. This has occurred in up to one-third of patients.[Ref]
Cardiovascular side effects have included hypotension, tachycardia, and palpitations.[Ref]
Ocular effects are due to the anticholinergic effects and may include blurred vision, diplopia, and dry eyes.[Ref]
Genitourinary side effects have included dysuria, urinary hesitancy, decrease in urine flow, and in rare cases, acute urinary retention.[Ref]
Hematologic side effects that have been reported with antihistamines include bone marrow suppression, thrombocytopenia, and aplastic anemia.[Ref]
A fatal case of agranulocytosis has been reported in a patient taking chlorpheniramine, pseudoephedrine, acetaminophen, dextromethorphan, phenylpropanolamine, and aspirin. Chlorpheniramine was felt to be the cause.[Ref]
Respiratory side effects have included thickening of bronchial secretions, wheezing, and tightness in the chest.[Ref]
At least one case of toxic pustuloderma has been reported during clemastine (the active ingredient contained in Leader Allerhist) therapy.[Ref]
Dermatologic side effects have included toxic pustuloderma.[Ref]
1. Schran HF, Petryk L, Chang CT, Oconnor R, Gelbert MB "The pharmacokinetics and bioavailability of clemastine and phenylpropanolamine in single-component and combination formulations." J Clin Pharmacol 36 (1996): 911-22
2. "Letter: Dyskinesia associated with chronic antihistamine use." N Engl J Med 294 (1976): 113
3. Frolund L, Etholm B, Irander K, Johannessen TA, Odkvist L, Ohlander B, Weeke B "A multicentre study of loratadine, clemastine and placebo in patients with perennial allergic rhinitis." Allergy 45 (1990): 254-61
4. "Product Information. Tavist (clemastine)." Sandoz Pharmaceuticals Corporation, East Hanover, NJ.
5. Schuller DE, Turkewitz D "Adverse effects of antihistamines." Postgrad Med 79 (1986): 75-86
6. Thomas JS, Heurich AE, Ralph JW, Crane R, Shepherd DA "Double-blind, controlled study of clemastine fumarate, chlorpheniramine and placebo in patients with seasonal allergic rhinitis." Ann Allergy 38 (1977): 169-74
7. Thach BT, Chase TN, Bosma JF "Oral facial dyskinesia associated with prolonged use of antihistaminic decongestants." N Engl J Med 293 (1975): 486-7
8. Turner RB, Sperber SJ, Sorrentino JV, OConnor RR, Rogers J, Batouli AR, Gwaltney JM "Effectiveness of clemastine fumarate for treatment of rhinorrhea and sneezing associated with the common cold." Clin Infect Dis 25 (1997): 824-30
9. Gwaltney JM, Park J, Paul RA, Edelman DA, Oconnor RR, Turner RB "Randomized controlled trial of clemastine fumarate for treatment of experimental rhinovirus colds." Clin Infect Dis 22 (1996): 656-62
10. Kanoh T, Jingami H, Uchino H "Aplastic anaemia after prolonged treatment with chlorpheniramine ." Lancet 1 (1977): 546-7
11. Deringer PM, Maniatis A "Chlorpheniramine-induced bone-marrow suppression." Lancet 1 (1976): 432
12. Eisner EV, LaBocki NL, Pinckney L "Chlorpheniramine-dependent thrombocytopenia." JAMA 231 (1975): 735-6
13. Hardin AS "Chlorpheniramine and agranulocytosis ." Ann Intern Med 108 (1988): 770
14. Feindkoopmans A, Vandervalk PGM, Steijlen PM, Vandekerkhof PCM "Toxic pustuloderma associated with clemastine therapy." Clin Exp Dermatol 21 (1996): 293-5
Not all side effects for Leader Allerhist may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.
More about Leader Allerhist (clemastine)
Related treatment guides
Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.