EAGLE ANTIHISTA

Indications

• Allergic rhinitis
• Hay fever
• Urticaria
• Pruritus
• Common cold symptoms

Dosage

Children: Refer to the BNF for Children for appropriate dosing recommendations based on age and weight.

Adults: Refer to the BNF for specific dosing guidelines based on the condition being treated.

Mechanism of action

Tripelennamine binds to the histamine H1 receptor, blocking the action of endogenous histamine. This competitive antagonism prevents histamine from exerting its effects on effector cells in the gastrointestinal tract, blood vessels, and respiratory tract. Consequently, tripelennamine alleviates symptoms such as urticaria and pruritus, and mitigates the vasodilatory and bronchoconstrictive actions of histamine.

Pharmacodynamics

As an antihistamine, tripelennamine counters the effects of histamine, which include pruritus, vasodilation, hypotension, and bronchoconstriction. By antagonizing H1 receptors, it provides temporary relief from symptoms of allergic rhinitis and other upper respiratory allergies, while also contributing to a reduction in symptoms associated with the common cold.

Pharmacokinetics

Tripelennamine is absorbed well from the gastrointestinal tract and distributes throughout body tissues. It undergoes hepatic metabolism and is excreted primarily via urine. The onset of action typically occurs within 1 to 2 hours, with a duration of effect that can vary based on individual metabolism and dosage.

Adverse effects

• Drowsiness
• Dizziness
• Dry mouth
• Blurred vision
• Constipation
• Urinary retention

Precautions

• Use with caution in patients with glaucoma, prostate hypertrophy, or asthma
• Avoid alcohol and other CNS depressants
• May cause sedation; caution when driving or operating machinery

Pregnancy

Tripelennamine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Consult a healthcare provider for guidance.

Breast-feeding

Tripelennamine is excreted in breast milk. Caution is advised when administered to nursing mothers.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Tablets
• Syrup

Mechanism of action

Tripelennamine 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. Antihistamines used in the treatment of allergy act by competing with histamine for H1-receptor sites on effector cells. They thereby prevent, but do not reverse, responses mediated by histamine alone. Antihistamines antagonize, in varying degrees, most of the pharmacological effects of histamine, including urticaria and pruritus. Also, the anticholinergic actions of most antihistamines provide a drying effect on the nasal mucosa. /Antihistamines/ H1 antagonists inhibit most responses of smooth muscle to histamine. Antagonism of the constrictor action of histamine on respiratory smooth muscle is easily shown in vivo and in vitro. /Histamine Antagonists: H1 Antagonists/ H1 antagonists strongly block the action of histamine that results in increased permeability and formation of edema and wheal. /Histamine Antagonists: H1 Antagonists/ Within the vascular tree, the H1 antagonists inhibit both the vasoconstrictor effects of histamine and, to a degree, the more rapid vasodilator effects that are mediated by H1 receptors on endothelial cells. Residual vasodilatation reflects the involvement of H2 receptors on smooth muscle and can be suppressed only by the concurrent administration of an H2 antagonist. Effects of the histamine antagonists on histamine induced changes in systemic blood pressure parallel these vascular effects. /Histamine Antagonists: H1 Antagonists/ Many of the H1 antagonists tend to inhibit responses to acetylcholine that are mediated by muscarinic receptors. These atropine like actions are sufficiently prominent in some of the drugs to be manifest during clinical usage ... . /Histamine Antagonists: H1 Antagonists/

Pharmacodynamics

Used to treat the effects of colds and allergies. Tripelennamine is an antihistamine. Histamine, acting on H₁-receptors, produces pruritis, vasodilatation, hypotension, flushing, headache, tachycardia, and bronchoconstriction. Histamine also increases vascular permeability and potentiates pain. Tripelennamine is a histamine H1 antagonist. 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.