Alhist
Alhist Uses, Dosage, Side Effects, Food Interaction and all others data.
Chlorpheniramine is an alkylamine antihistamine. It is one of the most potent H1 blocking agents and is generally effective in relatively low doses. Chlorpheniramine is not so prone to produce drowsiness, readily absorbed from the gastro-intestinal tract, metabolised in the liver and excreted usually mainly as metabolised in the urine.
In allergic reactions an allergen interacts with and cross-links surface IgE antibodies on mast cells and basophils. Once the mast cell-antibody-antigen complex is formed, a complex series of events occurs that eventually leads to cell-degranulation and the release of histamine (and other chemical mediators) from the mast cell or basophil. Once released, histamine can react with local or widespread tissues through histamine receptors. Histamine, acting on H1-receptors, produces pruritis, vasodilatation, hypotension, flushing, headache, tachycardia, and bronchoconstriction. Histamine also increases vascular permeability and potentiates pain. Chlorpheniramine, is a histamine H1 antagonist (or more correctly, an inverse histamine agonist) of the alkylamine class. It competes with histamine for the normal H1-receptor sites on effector cells of the gastrointestinal tract, blood vessels and respiratory tract. It provides effective, temporary relief of sneezing, watery and itchy eyes, and runny nose due to hay fever and other upper respiratory allergies.
Sodium citrate is the sodium salt of citric acid. It is white, crystalline powder or white, granular crystals, slightly deliquescent in moist air, freely soluble in water,practically insoluble in alcohol. Like citric acid, it has a sour taste.From the medical point of view, it is used as alkalinizing agent. It works by neutralizing excess acid in the blood and urine. It has been indicated for the treatment of metabolic acidosis.
Citrate prevents activation of the clotting cascade by chelating calcium ions. Citrate neutralizes acid in the stomach and urine, raising the pH .
| Trade Name | Alhist |
| Generic | Ammonium + Chlorpheniramine + Menthol + Sodium Citrate |
| Type | Syrup |
| Therapeutic Class | |
| Manufacturer | Agrawal Pharmaceuticals |
| Available Country | India |
| Last Updated: | September 19, 2023 at 7:00 am |
Uses
Indicated mainly in allergic conditions including urticaria, sensitivity reactions, angioneurotic oedema, seasonal hay fever, vasomotor rhinitis, cough, common cold, motion sickness.
Sodium citrate is an ingredient used for the anticoagulation of whole blood as part of automated apheresis procedures.
Used as an anticoagulant during plasmophoresis as well as a neutralizing agent in the treatment of upset stomach and acidic urine .
Alhist is also used to associated treatment for these conditions: Allergic Contact Dermatitis, Allergic Reaction, Allergic Rhinitis (AR), Allergic cough, Allergies, Allergies caused by Serum, Allergy to House Dust, Allergy to vaccine, Angioneurotic Edema, Asthma, Bronchial Asthma, Bronchitis, Common Cold, Conjunctival congestion, Conjunctivitis, Conjunctivitis allergic, Cough, Cough caused by Common Cold, Coughing caused by Flu caused by Influenza, Drug Allergy, Eye allergy, Fever, Flu caused by Influenza, Food Allergy, Headache, Headache caused by Allergies, Itching of the nose, Itching of the throat, Migraine, Nasal Congestion, Nasal Congestion caused by Common Cold, Pollen Allergy, Productive cough, Pruritus, Rash, Rhinorrhoea, Seasonal Allergic Conjunctivitis, Sinus Congestion, Sinusitis, Sneezing, Transfusion Reactions, Upper Respiratory Tract Infection, Upper respiratory tract hypersensitivity reaction, site unspecified, Urticaria, Vasomotor Rhinitis, Acute Rhinitis, Allergic purpura, Conjunctival hyperemia, Dry cough, Excess mucus or phlegm, Itchy throat, Mild bacterial upper respiratory tract infections, Ocular hyperemia, Throat inflammation, Upper airway congestion, Upper respiratory symptoms, Watery eyes, Watery itchy eyes, Airway secretion clearance therapyAcidosis, Allergic cough, Allergies, Asthma, Asthma Chronic, Cough, Common Cold, Cough, Coughing caused by Bronchitis, Dehydration, Gouty Arthritis, Heartburn, Metabolic Acidosis, Phlegm, Airway secretion clearance therapy, Oral rehydration therapy, Plasmapheresis, Urine alkalinization therapy, Fluid and electrolyte maintenance therapy, Irrigation during surgical procedures, Irrigation of the ocular surface therapy
How Alhist works
Chlorpheniramine binds to the histamine H1 receptor. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine.
Citrate chelates free calcium ions preventing them from forming a complex with tissue factor and coagulation factor VIIa to promote the activation of coagulation factor X . This inhibits the extrinsic initiation of the coagulation cascade. Citrate may also exert an anticoagulant effect via a so far unknown mechanism as restoration of calcium concentration does not fully reverse the effect of citrate . Citrate is a weak base and so reacts with hydrochloric acid in the stomach to raise the pH. It it further metabolized to bicarbonate which then acts as a systemic alkalizing agent, raising the pH of the blood and urine . It also acts as a diuretic and increases the urinary excretion of calcium.
Dosage
Alhist dosage
Adults: 4 mg 3-4 times daily.
Children:
- Up to 1( one) year: 1 mg twice daily
- 1-5 years: 1 mg 3-4 times daily
- 6-12 years: 2 mg 3-4 times daily or as directed by the physician
Side Effects
Drowsiness, dizziness, headache, psychomotor impairment, urinary retention, dry mouth, blurred vision and gastro intestinal disturbances, paradoxical stimulation may rarely occur, especially in high dosage or in children.
Toxicity
Oral LD50 (rat): 306 mg/kg; Oral LD50 (mice): 130 mg/kg; Oral LD50 (guinea pig): 198 mg/kg [Registry of Toxic Effects of Chemical Substances. Ed. D. Sweet, US Dept. of Health & Human Services: Cincinatti, 2010.] Also a mild reproductive toxin to women of childbearing age.
Overdose toxicity is mainly due to alkalosis as well as tetany or depressed heart function due to lack of free calcium .
Precaution
Chlorpheniramine may produce mild sedation and it is advised that patients under continuous treatment should avoid operating machinery. Not recommended during pregnancy & lactation.
Interaction
Alcohol, CNS depressants, anticholinergic drugs, MAOIs.
Volume of Distribution
19-39L .
Elimination Route
Well absorbed in the gastrointestinal tract.
Tmax of 98-130min .
Half Life
21-27 hours
18-54 min
Clearance
Total clearance of 313-1107mL/min .
Elimination Route
Largely eliminated through hepatic metabolism with very little cleared by the kidneys .
Pregnancy & Breastfeeding use
Pregnancy Category B. Either animal-reproduction studies have not demonstrated a foetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the 1st trimester (and there is no evidence of a risk in later trimesters).
Contraindication
There is no definite contraindication to therapy. It should be used with caution in epilepsy, prostatic hypertrophy, glaucoma and hepatic disease. The ability to drive or operate machinery may be impaired.
Innovators Monograph
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