WOOD'S PEPPERMINT COUGH SYRUP (Each 7ml sachet contains Dextromethophan hydrobromide/Guaifenesin/ Chlorpheniramine Maleate 15mg/ 100mg/ 2mg)

Indications

• Allergic rhinitis (hay fever)
• Urticaria (hives)
• Allergic conjunctivitis
• Common cold symptoms

Dosage

Children: For children aged 6-12 years, the dose is typically 2 mg every 4 to 6 hours, not exceeding 12 mg per day. For children under

Adults: The usual adult dose for chlorpheniramine is 4 mg every 4 to 6 hours, not to exceed 24 mg per day.

Mechanism of action

Chlorpheniramine binds to the histamine H1 receptor, preventing endogenous histamine from exerting its effects. This leads to temporary relief from symptoms such as sneezing, pruritus, and increased vascular permeability associated with allergic reactions. The drug competes with histamine for H1-receptor sites on effector cells, thus antagonizing most of the pharmacological effects of histamine, including its actions on smooth muscle and vascular permeability.

Pharmacodynamics

In allergic reactions, allergens trigger the degranulation of mast cells and basophils, leading to the release of histamine. Chlorpheniramine, as an H1 antagonist, competes for receptor binding, effectively blocking histamine-induced effects, such as itching, vasodilation, and bronchoconstriction. This results in relief from symptoms like sneezing, watery eyes, and nasal discharge.

Pharmacokinetics

Chlorpheniramine is well absorbed from the gastrointestinal tract. It undergoes hepatic metabolism and its effects can last for several hours. The onset of action is typically observed within 1 to 2 hours following oral administration, with peak effects occurring around 2 to 6 hours. The drug is eliminated primarily through urine, with a half-life ranging from 12 to 15 hours, though this can vary based on individual factors.

Contra-indications

• Hypersensitivity to chlorpheniramine or any component of the formulation
• Acute asthma attacks
• Severe hypertension
• Narrow-angle glaucoma
• Prostatic hypertrophy

Adverse effects

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

Interactions

• Alcohol
• CNS depressants
• MAO inhibitors
• Anticholinergic agents
• Beta-blockers

Precautions

• Use with caution in patients with cardiovascular disease
• Caution in patients with liver or kidney impairment
• Avoid in elderly patients due to increased risk of sedation and anticholinergic effects
• May impair the ability to drive or operate machinery

Pregnancy

Chlorpheniramine should be used in pregnancy only if clearly needed. Consult medical professionals for guidance.

Breast-feeding

Chlorpheniramine is excreted in breast milk. Caution is advised when administering to nursing mothers.

Storage

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

Formulations

• Tablets
• Syrup
• Oral suspension

Indications

• Cough associated with the common cold
• Cough due to bronchitis
• Cough caused by upper respiratory tract infections

Dosage

Children: Refer to established medical guidelines or product labeling for specific dosing recommendations.

Adults: Refer to established medical guidelines or product labeling for specific dosing recommendations.

Mechanism of action

Dextromethorphan primarily acts as a non-competitive antagonist at the NMDA receptor and inhibits the reuptake of serotonin, which contributes to its cough-suppressing effects. It also has sigma-1 receptor agonist properties, which may play a role in its analgesic and anti-cough effects.

Pharmacodynamics

Dextromethorphan reduces the frequency and intensity of coughing. It does this by acting on the medullary cough center in the central nervous system, decreasing the sensitivity to cough stimuli. Its effects can typically be observed within 15 to 30 minutes after oral administration, lasting for several hours.

Pharmacokinetics

Dextromethorphan is rapidly absorbed from the gastrointestinal tract, with peak plasma concentrations occurring within 2 to 3 hours post-administration. It undergoes extensive hepatic metabolism primarily via the cytochrome P450 system, particularly CYP2D6, resulting in various metabolites. The elimination half-life of dextromethorphan is approximately 2 to 4 hours, and it is excreted in urine, predominantly as metabolites.

Adverse effects

• Dizziness
• Nausea
• Drowsiness
• Constipation
• Stomach upset
• Allergic reactions

Interactions

• MAO inhibitors
• Alcohol
• CNS depressants
• Serotonergic drugs

Precautions

• Use with caution in patients with a history of substance abuse
• May cause respiratory depression in high doses
• Not recommended for use in children under 2 years of age
• Monitor for symptoms of serotonin syndrome when used with other serotonergic agents

Pregnancy

Dextromethorphan is classified as category C. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Dextromethorphan 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

• Oral syrup
• Tablets
• Extended-release capsules
• Lozenges

Indications

• Cough associated with respiratory tract infections
• Cough due to bronchial asthma
• Acute bronchitis
• Chronic obstructive pulmonary disease (COPD)
• Sinusitis

Dosage

Children: For children aged 6 to 12 years, the typical dosage is 100-200 mg every 4 hours as needed, not exceeding 1.2 g in 24 hours. For children aged 2 to 6 years, the dosage is generally 50-100 mg every 4 hours as needed, not exceeding 600 mg in 24 hours. Refer to the BNF for Children for specific dosing recommendations.

Adults: The usual adult dosage for guaifenesin is 200-400 mg every 4 hours as needed, not exceeding 2.4 g in 24 hours.

Mechanism of action

Guaifenesin is believed to work by increasing mucus secretion and acting as an irritant to gastric vagal receptors, which stimulates efferent parasympathetic reflexes. This leads to glandular exocytosis of less viscous mucus. Additionally, it may enhance respiratory tract fluid, thereby reducing the viscosity of secretions and improving ciliary action for more efficient mucus clearance.

Pharmacodynamics

As an expectorant, guaifenesin enhances the output of bronchial secretions and phlegm by decreasing their adhesiveness and surface tension. This results in an increased flow of less viscous gastric secretions, promoting ciliary action and converting unproductive coughs into more productive ones. Although it may also exhibit mild anticonvulsant and muscle relaxant properties, these effects are less well established.

Pharmacokinetics

Guaifenesin is rapidly absorbed from the gastrointestinal tract and reaches peak plasma concentrations within one hour of administration. It is metabolized in the liver, and its elimination half-life is approximately one hour. The drug is primarily excreted in the urine, mostly as metabolites.

Adverse effects

• Nausea
• Vomiting
• Dizziness
• Headache
• Rash

Precautions

• Use with caution in patients with chronic cough due to asthma, smoking, or emphysema
• Ensure adequate hydration while using

Pregnancy

Guaifenesin is categorized as pregnancy category C. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Guaifenesin is excreted in breast milk. Caution should be exercised when administered to breastfeeding women.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Oral syrup
• Tablets
• Extended-release capsules

Indications

• Respiratory conditions (e.g., asthma, chronic obstructive pulmonary disease)
• Cough (e.g., as an antitussive)
• Anxiety and sleep disorders (when associated with specific formulations)

Dosage

Children: Refer to the BNF for Children for appropriate dosing information, as it is determined based on weight and age for the specific formulation.

Adults: Refer to the specific product monograph for dosing information, as it varies based on the drug formulation and indication.

Mechanism of action

Hydrobromides often act as competitive antagonists or agonists at specific receptor sites, depending on the drug involved. The exact mechanism can vary widely, but many hydrobromide-containing drugs modulate neurotransmitter activity, impacting various pathways in the body such as those involved in the central nervous system or respiratory function. The metabolic pathways include Phase I reactions primarily mediated by cytochrome P450 enzymes, which facilitate the functionalization and clearance of these compounds.

Pharmacodynamics

The pharmacodynamics of hydrobromide salts are largely determined by the specific drug they are associated with. Generally, hydrobromides may exhibit effects such as sedation, bronchodilation, or antitussive actions. The efficacy and adverse effects are influenced by the drug's receptor selectivity, affinity, and the pharmacological properties inherent to the parent compound.

Pharmacokinetics

Hydrobromides typically exhibit variable pharmacokinetic profiles depending on the specific drug formulation. They are generally absorbed rapidly following oral administration, with peak plasma concentrations occurring within a few hours. Metabolism primarily occurs in the liver through cytochrome P450 enzymes, particularly CYP2E1, among others. The elimination half-life varies but is often in the range of several hours, allowing for once or twice-daily dosing in many formulations. Excretion is usually via the kidneys, with metabolites being eliminated in urine.

Pregnancy

There are no adequate and well-controlled studies in pregnant women. Use only if clearly needed and the potential benefits justify the potential risks to the fetus.

Breast-feeding

Caution is advised; consider the importance of the drug to the mother against potential risks to the breastfeeding infant.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Mechanism of action

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. 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

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.

Mechanism of action

Although the exact mechanism of action of guaifenesin may not yet be formally or totally elucidated, it is believed that expectorants like guaifenesin function by increasing mucus secretion. Moreover, it is also further proposed that such expectorants may also act as an irritant to gastric vagal receptors, and recruit efferent parasympathetic reflexes that can elicit glandular exocytosis that is comprised of a less viscous mucus mixture. Subsequently, these actions may provoke coughing that can ultimately flush difficult to access, congealed mucopurulent material from obstructed small airways to facilitate a temporary improvement for the individual. Consequently, while it is generally proposed that guaifenesin functions as an expectorant by helping to loosen phlegm (mucus) and thin bronchial secretions to rid the bronchial passageways of bothersome mucus and make coughs more productive, there has also been research to suggest that guaifenesin possesses and is capable of demonstrating anticonvulsant and muscle relaxant effects to some degree possibly by acting as an NMDA receptor antagonist. Guaifenesin is thought to act as an expectorant by increasing the volume and reducing the viscosity of secretions in the trachea and bronchi. Thus it may increase the efficiency of the cough reflex and facilitate removal of the secretions; however, objective evidence for this is limited and conflicting. By increasing respiratory tract fluid, guaifenesin reduces the viscosity of tenacious secretions and acts as an expectorant. Guaifenesin, a commonly used agent for the treatment of cough, is termed an expectorant since it is believed to alleviate cough discomfort by increasing sputum volume and decreasing its viscosity, thereby promoting effective cough. Despite its common usage, relatively few studies, yielding contrasting results, have been performed to investigate the action and efficacy of guaifenesin. To evaluate the effect of guaifenesin on cough reflex sensitivity. Randomized, double-blind, placebo-controlled trial. Fourteen subjects with acute viral upper respiratory tract infection (URI) and 14 healthy volunteers. On 2 separate days, subjects underwent capsaicin cough challenge 1 to 2 hr after receiving a single, 400-mg dose (capsules) of guaifenesin or matched placebo. Measurements and results: The concentration of capsaicin inducing five or more coughs (C(5)) was determined. Among subjects with URI, mean (+/- SEM) log C(5) after guaifenesin and placebo were 0.92 +/- 0.17 and 0.66 +/- 0.14, respectively (p = 0.028). No effect on cough sensitivity was observed in healthy volunteers. /The/ results demonstrate that guaifenesin inhibits cough reflex sensitivity in subjects with URI, whose cough receptors are transiently hypersensitive, but not in healthy volunteers. Possible mechanisms include a central antitussive effect, or a peripheral effect by increased sputum volume serving as a barrier shielding cough receptors within the respiratory epithelium from the tussive stimulus.

Pharmacodynamics

Guaifenesin is categorized as an expectorant that acts by enhancing the output of phlegm (sputum) and bronchial secretions via decreasing the adhesiveness and surface tension of such material. Furthermore, guaifenesin elicits an increased flow of less viscous gastric secretions that subsequently promote ciliary action - all actions that ultimately change dry, unproductive coughing to coughs that are more productive and less frequent. Essentially, by decreasing the viscosity and adhesiveness of such secretions, guaifenesin enhances the efficacy of mucociliary activity in removing accumulated secretions from the upper and lower airway.