ACTIFED EXPECTORANT

Indications

• Nasal congestion
• Sinusitis affecting the maxillary antrum

Dosage

Children: For children aged 6-11 years, the recommended dose is 30 mg 3-4 times a day. For children aged 12-17 years, the dose is 60 mg 3-4 times a day. Caution is advised in children under 6 years.

Adults: The typical adult dose is 60 mg every 4-6 hours, not exceeding 240 mg per day.

Mechanism of action

Pseudoephedrine acts primarily as a selective agonist of alpha-adrenergic receptors, which causes vasoconstriction of the nasal mucosa. This leads to a decrease in mucosal edema and congestion. It may also have some beta-adrenergic activity, contributing to bronchodilation.

Pharmacodynamics

The pharmacodynamic effects of pseudoephedrine include reduced nasal congestion and increased airflow through the nasal passages. Its action is dose-dependent, with higher doses leading to more pronounced effects. Side effects may include increased heart rate, hypertension, and CNS stimulation such as anxiety and insomnia.

Pharmacokinetics

Pseudoephedrine is well absorbed from the gastrointestinal tract, with peak plasma concentrations occurring within 1-2 hours after oral administration. It is metabolized primarily in the liver and has a half-life of approximately 5-8 hours. The drug is excreted mainly in the urine, with a portion being unchanged.

Contra-indications

• Severe hypertension
• Severe renal impairment
• Severe hepatic impairment
• Hyperthyroidism
• Angle closure glaucoma
• Use in children under 6 years of age is not recommended due to safety concerns

Adverse effects

• Anxiety
• Headache
• Insomnia
• Nausea
• Dizziness
• Dry mouth
• Increased heart rate (tachycardia)
• Hypertension
• Palpitations
• Rebound congestion
• Irritability
• Tremors
• Hallucinations
• Dermatitis
• Muscle weakness
• Vomiting
• Piloerection

Interactions

• Monoamine oxidase inhibitors (MAOIs) may enhance the hypertensive effects
• Other sympathomimetics may increase the risk of cardiovascular effects
• Caution with antihypertensive medications as pseudoephedrine may counteract their effectiveness

Precautions

• Use with caution in individuals with cardiovascular disease
• Caution in patients with diabetes due to potential hyperglycemia
• Monitor patients with a history of psychiatric disorders as it may exacerbate symptoms
• Use with caution in patients with a history of seizures

Pregnancy

Manufacturer advises avoidance due to potential risks such as defective closure of the abdominal wall in newborns after first trimester exposure.

Breast-feeding

Present in breast milk; manufacturer advises avoidance due to the potential for irritability and disturbed sleep in infants.

Storage

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

Formulations

• Oral solution (e.g., Sudafed Decongestant 30mg/5ml liquid)
• Nasal drops (e.g., Galpseud 0.5% drops)

Indications

• Cough associated with colds
• Bronchitis
• Respiratory tract infections
• Other conditions with excessive mucus production

Dosage

Children: Refer to the BNF for Children for specific dosing guidelines based on age and

Adults: The typical adult dose is 200-400 mg orally every 4 hours as needed, not exceeding 2.4 g per day.

Mechanism of action

Guaifenesin is believed to function by increasing mucus secretion and acting as an irritant to gastric vagal receptors. This action recruits efferent parasympathetic reflexes that stimulate glandular exocytosis, resulting in a less viscous mucus mixture. Consequently, this may provoke coughing, facilitating the clearance of congealed mucopurulent material from obstructed airways, thereby improving respiratory function. Additionally, it is thought to enhance the output of phlegm and bronchial secretions by reducing their viscosity and adhesiveness, thus promoting ciliary action and improving the efficiency of the cough reflex.

Pharmacodynamics

Guaifenesin acts as an expectorant that enhances the output of phlegm and bronchial secretions by decreasing their adhesiveness and surface tension. By increasing the flow of less viscous gastric secretions, it promotes ciliary action, leading to more productive coughs. This mechanism ultimately aids in the removal of accumulated secretions from the upper and lower airways, making coughs less frequent and more effective.

Pharmacokinetics

Guaifenesin is rapidly absorbed from the gastrointestinal tract and is metabolized in the liver. It has a relatively short half-life, with peak plasma concentrations typically occurring within one hour of administration. The drug is eliminated primarily through renal excretion, with both unchanged drug and metabolites being excreted in the urine.

Adverse effects

• Nausea
• Vomiting
• Dizziness
• Headache
• Rash
• Gastrointestinal discomfort

Precautions

• Caution in patients with chronic cough associated with smoking, asthma, or emphysema
• Use with caution in patients with a history of gastrointestinal disorders

Pregnancy

Guaifenesin is categorized under FDA pregnancy category C. Risk cannot be ruled out; consult a healthcare provider.

Breast-feeding

Limited data available; exercise caution and consult a healthcare provider before use.

Storage

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

Formulations

• Oral solution
• Tablet
• Extended-release tablet
• Syrup

Indications

• Nasal congestion due to cold
• Allergic rhinitis
• Sinusitis
• Eustachian tube dysfunction

Dosage

Children: For children aged 6 to 12 years, the recommended dose is 30 mg every 6 hours, not exceeding 120 mg per day. For children aged 2 to 6 years

Adults: The typical adult dose is 60 mg every 4 to 6 hours, not exceeding 240 mg per day.

Mechanism of action

Pseudoephedrine acts mainly as an agonist of alpha adrenergic receptors and less strongly as an agonist of beta adrenergic receptors. The agonism produces vasoconstriction in the mucosa of the respiratory tract, leading to decreased nasal congestion. It also inhibits norepinephrine, dopamine, and serotonin transporters, which may contribute to its sympathomimetic effects such as increased arterial pressure and heart rate. Additionally, pseudoephedrine has anti-inflammatory actions through the inhibition of NF-kappa-B and other transcription factors.

Pharmacodynamics

Pseudoephedrine causes vasoconstriction resulting in a decongestant effect. Its sympathomimetic properties can lead to increased heart rate and blood pressure. The duration of action is typically short unless formulated as an extended-release product. Patients may experience central nervous system stimulation, which should be considered when prescribing.

Pharmacokinetics

Pseudoephedrine is well absorbed from the gastrointestinal tract, with peak plasma concentrations occurring approximately 1 to 2 hours after oral administration. The drug is metabolized in the liver, primarily by the cytochrome P450 system, and has a half-life of about 6 hours. It is excreted mainly through the kidneys, with about 55-70% of the dose eliminated unchanged in the urine.

Adverse effects

• Increased blood pressure
• Centrally mediated side effects such as insomnia
• Nervousness
• Dizziness
• Headache
• Dry mouth

Interactions

• pseudoephedrine + linezolid: Severe (increases risk of elevated blood pressure)
• volatile halogenated anesthetics + pseudoephedrine: Unknown (additive effect)

Precautions

• Use with caution in patients with hypertension
• Use with caution in patients with cardiovascular disease
• May exacerbate conditions like hyperthyroidism or diabetes

Pregnancy

Use only if clearly needed, as safety in pregnancy has not been established.

Breast-feeding

Use with caution; small amounts may pass into breast milk.

Storage

Store at room temperature, away from moisture and heat.

Formulations

• Oral tablets
• Extended-release oral tablets
• Liquid formulations

Indications

• Allergic rhinitis (hay fever)
• Allergic conjunctivitis
• Urticaria (hives)
• Other upper respiratory allergies

Dosage

Children: For children aged 2 to 6 years, the recommended dose is 1.25 mg to 2.5 mg taken

Adults: The usual adult dose for triprolidine is 2.5 mg to 5 mg taken orally, one to three times daily, as needed. Refer to the BNF for specific dosing recommendations.

Mechanism of action

Triprolidine binds to the histamine H1 receptor, inhibiting the action of endogenous histamine. By competing with histamine for H1-receptor sites on effector cells, it prevents the physiological responses mediated by histamine, such as pruritus, urticaria, and bronchoconstriction. The drug's anticholinergic effects also contribute to reduced secretion in the nasal mucosa.

Pharmacodynamics

In allergic reactions, allergens interact with surface IgE antibodies on mast cells, leading to degranulation and release of histamine. Histamine acts on H1-receptors to produce various effects, including itching, vasodilatation, and increased vascular permeability. Triprolidine, as an H1 antagonist, competes with histamine for receptor binding, effectively blocking these reactions and providing relief from allergy symptoms.

Pharmacokinetics

Triprolidine is absorbed well following oral administration, with peak plasma concentrations typically occurring within 2 to 4 hours. It has a relatively long half-life, allowing for sustained effects. The drug is metabolized in the liver and primarily excreted via urine. Due to its ability to cross the blood-brain barrier, triprolidine may also cause sedation as a side effect.

Adverse effects

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

Precautions

• Use with caution in patients with a history of glaucoma
• May exacerbate urinary retention in patients with prostatic hypertrophy
• Caution in driving or operating machinery due to sedative effects

Pregnancy

Triprolidine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Consult with a healthcare provider.

Breast-feeding

It is not known whether triprolidine is excreted in human 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

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.

Mechanism of action

Pseudoephedrine acts mainly as an agonist of alpha adrenergic receptors and less strongly as an agonist of beta adrenergic receptors. This agonism of adrenergic receptors produces vasoconstriction which is used as a decongestant and as a treatment of priapism. Pseudoephedrine is also an inhibitor of norepinephrine, dopamine, and serotonin transporters. The sympathomimetic effects of pseudoephedrine include an increase in mean arterial pressure, heart rate, and chronotropic response of the right atria. Pseudoephedrine is also a partial agonist of the anococcygeal muscle. Pseudoephedrine also inhibits NF-kappa-B, NFAT, and AP-1. THESE AGENTS /BRONCHODILATORS/ ACT ON BETA-2 RECEPTORS TO RELAX BRONCHIAL SMOOTH MUSCLE & PERIPHERAL VASCULATURE, APPARENTLY BY STIMULATING PRODN OF CYCLIC ADENOSINE-3.5-MONOPHOSPHATE (CAMP)... Pseudoephedrine acts on alpha-adrenergic receptors in the mucosa of the respiratory tract, producing vasoconstriction. The medication shrinks swollen nasal mucous membranes; reduces tissue hyperemia, edema, and nasal congestion; and increases nasal airway patency. Also, drainage of sinus secretions may be increased and obstructed eustachian ostia may be opened. The pharmacological properties of the ephedrine derivative pseudoephedrine were investigated at the nuclear level. Following intraperitoneal injection of Sprague Dawley rats with pseudoephedrine, Fos induction was measured in various brain areas by Western blots and immunocytochemistry. Pseudoephedrine induced Fos-like immunoreactivity in the nucleus accumbens and striatum in a time and concentration-dependent manner with maximal effect at 60 mg/kg 2 hr after injection. Immunocytochemical studies confirmed that the majority of the signal was detectable in the nucleus accumbens and striatum. Pre-injection with the D1 dopamine receptor antagonist SCH23390 partially and completely blocked pseudoephedrine-induced Fos-like immunoreactivity in the striatum and nucleus accumbens, respectively, suggesting that the action of pseudoephedrine is mediated via dopamine release and results in the activation of D1 dopamine receptors. With the exception of the higher doses required, the actions of pseudoephedrine were similar to those previously described for the psychostimulant amphetamine.

Pharmacodynamics

Pseudoephedrine causes vasoconstriction which leads to a decongestant effect. It has a short duration of action unless formulated as an extended release product. Patients should be counselled regarding the risk of central nervous system stimulation.

Mechanism of action

Triprolidine 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/ 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/ /SRP:/ The action of histamine results in increased permeability and formation of edema and wheal. H1 antagonists block that action. For more Mechanism of Action (Complete) data for TRIPROLIDINE (7 total), please visit the HSDB record page.

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. Triprolidine, is a histamine H1 antagonist that 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. Triprolidine has anticholinergic and sedative effects.