Chlor-Trimeton Side Effects
Generic Name: chlorpheniramine
Note: This page contains information about the side effects of chlorpheniramine. Some of the dosage forms included on this document may not apply to the brand name Chlor-Trimeton.
Not all side effects for Chlor-Trimeton may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.
For the Consumer
Applies to chlorpheniramine: capsules, controlled-release capsules, suspension drops, sustained-release capsules, syrup, tablets
Other dosage forms:
Check with your doctor if any of these most COMMON side effects persist or become bothersome:
Seek medical attention right away if any of these SEVERE side effects occur while taking chlorpheniramine (the active ingredient contained in Chlor-Trimeton)
Constipation; diarrhea; dizziness; drowsiness; dry mouth, nose, or throat; excitability; headache; loss of appetite; nausea; nervousness or anxiety; trouble sleeping; upset stomach; vomiting; weakness.
Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); difficulty urinating or inability to urinate; fast or irregular heartbeat; hallucinations; seizures; severe dizziness, lightheadedness, or headache; tremor; trouble sleeping; vision changes.
For Healthcare Professionals
Applies to chlorpheniramine: compounding powder, injectable solution, oral capsule extended release, oral liquid, oral suspension extended release, oral syrup, oral tablet, oral tablet chewable, oral tablet extended release
Central nervous system side effects have included depression resulting in drowsiness in 75% or more of treated patients. Dyskinesias have rarely been reported following chronic use of chlorpheniramine (the active ingredient contained in Chlor-Trimeton) [Ref]
Nearly all patients treated with chlorpheniramine experience drowsiness. This drowsiness may subside in some patients with extended use.
Few cases of dyskinesias and tremors, often of the face, have been reported in patients whose chronic use of chlorpheniramine 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 in up to one-third of treated patients.[Ref]
Cardiovascular side effects have included hypotension, tachycardia, and palpitations.[Ref]
Ocular side effects of chlorpheniramine (the active ingredient contained in Chlor-Trimeton) may include blurred vision, diplopia, and dry eyes due to anticholinergic effects.[Ref]
Genitourinary side effects have included dysuria, urinary hesitancy, and a decreased urine flow. In rare cases, the anticholinergic effect of chlorpheniramine (the active ingredient contained in Chlor-Trimeton) has precipitated acute urinary retention.[Ref]
Hematologic side effects have included 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]
1. "Letter: Dyskinesia associated with chronic antihistamine use." N Engl J Med 294 (1976): 113
2. Millet VM, Dreisbach M, Bryson YJ "Double-blind controlled study of central nervous system side effects of amantadine, rimantadine, and chlorpheniramine." Antimicrob Agents Chemother 21 (1982): 1-4
3. Krause LB, Shuster S "A comparison of astemizole and chlorpheniramine in dermographic urticaria." Br J Dermatol 112 (1985): 447-53
4. Schuller DE, Turkewitz D "Adverse effects of antihistamines." Postgrad Med 79 (1986): 75-86
5. 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
6. Bantz EW, Dolen WK, Chadwick EW, Nelson HS "Chronic chlorpheniramine therapy: subsensitivity, drug metabolism, and compliance." Ann Allergy 59 (1987): 341-6
7. Weiler JM, Donnelly A, Campbell BH, Connell JT, Diamond L, Hamilton LH, Rosenthal RR, Hemsworth GR, Perhach JL, Jr "Multicenter, double-blind, multiple-dose, parallel-groups efficacy and safety trial of azelastine, chlorpheniramine, and placebo in the treatment of spring allergic rhinitis." J Allergy Clin Immunol 82 (1988): 801-11
8. Thach BT, Chase TN, Bosma JF "Oral facial dyskinesia associated with prolonged use of antihistaminic decongestants." N Engl J Med 293 (1975): 486-7
9. "Product Information. Chlortrimeton (chlorpheniramine)." Schering-Plough, Liberty Corner, NJ.
10. Deringer PM, Maniatis A "Chlorpheniramine-induced bone-marrow suppression." Lancet 1 (1976): 432
11. Eisner EV, LaBocki NL, Pinckney L "Chlorpheniramine-dependent thrombocytopenia." JAMA 231 (1975): 735-6
12. Hardin AS "Chlorpheniramine and agranulocytosis ." Ann Intern Med 108 (1988): 770
13. Kanoh T, Jingami H, Uchino H "Aplastic anaemia after prolonged treatment with chlorpheniramine ." Lancet 1 (1977): 546-7
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