CHLOROHISTOL – Antihistamine Ampoules

Composition:  Each ampoule contains: Chlorpheniramine maleate 10mg/1ml.. or 20mg/ 2ml.For S.C./I.M./I.V. injection.


CHLOROHISTOL injection is indicated in the emergency treatment of anaphylaxis and angioedema as an adjunct to adrenaline (epinephrine) and other standard measures.

CHLOROHISTOL injection can also be used for the symptomatic relief of allergy such as acute urticaria, allergic reactions to insect bites and stings, drug and food reactions and severe pruritus of non-specific origin. CHLOROHISTOL AMPOULE – PIL

كلورهيستول أمبول حقن CHLORHISTOL AMPOULE
كلورهيستول أمبول حقن CHLORHISTOL AMPOULE



Adults: The usual dose is 10 – 20mg as a single dose. maximum dose should not normally exceed 40mg in a 24-hour period.

Children: The usual recommended dose is: 

  • Infants 1 month to 1 year: 0.25mg/kg. 
  • Children 1 to 12 years: 0.20mg/kg.

alternatively, the paediatric dose may be expressed in term of age: 

  • Children 1 to 5 years: 2.5 to 5mg. 
  • Children 6 to 12 years: 5 to 10mg. 


  • CHLOROHISTOL ampoules may be given by subcutaneous, intramuscular or slow intravenous injection over a period of 1 minute.
  • When a rapid effect is desired, as in anaphylactic reactions, the intravenous route is recommended.
  • Extra care should be taken when preparing the injection for children under 1 year due to the small volumes that are required. Dilution of CHLOROHISTOL injection with sodium chloride intravenous infusion (0.9% w/v) should facilitate preparation. The diluted product should be used immediately.


  • Hypersensitivity to any component of the product. 
  • Severe liver disease, since sedation is inappropriate.


  • Chlorpheniramine, in common with other drugs having anticholinergic (antimuscarinic) effects, should be used with caution in patients having prostatic hypertrophy, urinary retention, glaucoma and pyloroduodenal obstruction.
  • Caution may also be required in patients having epilepsy, severe hypertension, cardiovascular disease, bronchitis and asthma, hepatic disease and thyrotoxicosis. 
  • It should also be used with caution in children and elderly patients as they are more susceptible to side effects.
  • Since chlorpheniramine may cause drowsiness, patients should be warned against driving motor vehicles or operating hazardous machinery.
  • The use of chlorpheniramine is considered safe in patients having porphyria.


Since adequate and well-controlled studies on the use of chlorpheniramine in humans have not been done, it should only be used during pregnancy when clearly needed and when the potential benefits of treatment to the mother outweigh the possible risks to the fetus. Use during the third trimester may result in reactions in neonates.


It is reasonable to assume that chlorpheniramine,  as with other similar antihistamines, may inhibit lactation because of its anticholinergic (antimuscarinic) activity. Small amounts of chlorpheniramine are distributed into breast milk; use in lactating mothers requires that the therapeutic benefits of the drug to the mother should be weighed against the potential risks (such as unusual excitement or irritability) to the infant.

Side Effects 

  • CHLOROHISTOL is usually well tolerated. Some minor side effects have occasionally been reported such as drowsiness, which may diminish after a few days of continued treatment.However, paradoxical stimulation may occur rarely. especially with high doses or in children and elderly.
  • Other side effects which have been reported less frequently include headache, psychomotor impairment and anticholinergic (antimuscarinic) effects such as urinary retention, dry mouth, blurred vision and gastro-intestinal disturbances. 
  • Hypersensitivity reactions including bronchospasm, angioedema,anaphylaxis, rashes and photosensitivity reactions have also been reported less frequently. 
  • Other rare side effects include tinnitus, extrapyramidal effects, dizziness, confusion, depression, sleep disturbances, tremor, convulsions, palpitation, arrhythmias, hypotension, blood disorders, liver dysfunction and exfoliative dermatitis have been reported.
  • Injections may be irritant as some patients have reported a stinging or burning sensation at the site of injection. 
  • Rapid intravenous injection may cause transient hypotension or CNS stimulation.


Chlorpheniramine (chlorphenamine), the active ingredient of CHLOROHISTOL, is a potent antihistamine that completely abolishes the signs and symptoms of allergy resulting from histamine release. It competes with histamine for H1-receptor sites on cells and tissues. It also has anticholinergic (antimuscarinic) activity.

Chlorpheniramine is approximately 70% bound to plasma proteins. The plasma half-life has been estimated to be 12 to 15 hours. It is widely distributed in the body, including passage into the CNS and probably produces sedation largely by occupying H1.-receptors in the brain.

It is extensively metabolised.Unchanged drug and metabolites are excreted in the urine. The clearance of chlorpheniramine is faster in children than adults and the elimination half-life may be shorter.

Patient Information Leaflet

ENG - Patient Information Leaflet
Chlorohistol ampoules – Patient Information Leaflet
كلوروهيستول حقن – النشرة الداخلية

Categories and tags: R06AB04, Chlorphenamine, Substituted alkylamines, ANTIHISTAMINES FOR SYSTEMIC USE, ANTIHISTAMINES FOR SYSTEMIC USE, RESPIRATORY SYSTEM. Alternatives: Chlorohistol ampoules, Avil ampoules.

For Arabic Information
Chlorohistol ampoules- Arabic Information

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