Histalong
Histalong Uses, Dosage, Side Effects, Food Interaction and all others data.
Histalong is a long-acting, non-sedating second generation antihistamine used in the treatment of allergy symptoms. It was withdrawn from market by the manufacturer in 1999 due to the potential to cause arrhythmias at high doses, especially when when taken with CYP inhibitors or grapefruit juice.
Histalong is a second generation H1-receptor antagonist. It does not significantly cross the blood brain barrier and therefore does not cause drowsiness or CNS depression at normal doses.
| Trade Name | Histalong |
| Availability | Discontinued |
| Generic | Astemizole |
| Astemizole Other Names | Astemizol, Astémizole, Astemizole, Astemizolum |
| Related Drugs | hydroxyzine, loratadine, levocetirizine, Vistaril, Atarax, Xyzal |
| Weight | 10mg, 5mg, |
| Type | Tablet |
| Formula | C28H31FN4O |
| Weight | Average: 458.5703 Monoisotopic: 458.248189839 |
| Protein binding | 96.7% |
| Groups | Approved, Withdrawn |
| Therapeutic Class | |
| Manufacturer | Stangan Pharma -2 |
| Available Country | India, |
| Last Updated: | September 19, 2023 at 7:00 am |
Uses
Histalong is a second generation antihistamine used to treat allergy symptoms.
Histalong was indicated for use in the relieving allergy symptoms, particularly rhinitis and conjunctivitis. It has been withdrawn from the market however due to concerns of arrhythmias.
How Histalong works
Histalong competes with histamine for binding at H1-receptor sites in the GI tract, uterus, large blood vessels, and bronchial muscle. This reversible binding of astemizole to H1-receptors suppresses the formation of edema, flare, and pruritus resulting from histaminic activity. As the drug does not readily cross the blood-brain barrier and preferentially binds at H1 receptors in the peripehery rather than within the brain, CNS depression is minimal. Histalong may also act on H3-receptors, producing adverse effects.
Toxicity
LD50=2052mg/kg in mice
Food Interaction
- Take on an empty stomach. Food decreases absorption.
[Major] GENERALLY AVOID: Some beverages such as tonic water contain varying amounts of quinine.
Coadministration of a single 430 mg dose of quinine has been shown to increase plasma concentrations of astemizole and its metabolite, desmethylastemizole.
Elevated levels of these agents may cause a prolongation of the electrocardiographic QT interval and potentially fatal ventricular arrhythmias.
Although pharmacokinetic data have indicated that the amounts of quinine in beverages (up to 80 mg quinine in 32 oz of tonic water) are not sufficient to produce a significant effect, the potential for an interaction exists if large amounts of tonic water are ingested.
Also, grapefruit juice has been shown to inhibit CYP450 enzymes, which may lead to increased serum astemizole concentrations.
The risk of life-threatening ventricular arrhythmias may be increased.
MANAGEMENT: Patients should be counseled to limit consumption of quinine-containing beverages and avoid grapefruit juice while they are taking astemizole.
Histalong Drug Interaction
Major: clotrimazole, clotrimazoleUnknown: acetaminophen, acetaminophen, aspirin, aspirin, alprazolam, alprazolam, amobarbital, amobarbital, pseudoephedrine / triprolidine, pseudoephedrine / triprolidine, penicillin g benzathine, penicillin g benzathine, methohexital, methohexital, remimazolam, remimazolam, carboplatin, carboplatin
Elimination Route
Rapidly absorbed from the gastrointestinal tract.
Half Life
1 day
Innovators Monograph
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