Mucolyn syrup

Indications

• Nitrogen supplementation in clinical nutrition
• Management of metabolic alkalosis
• Treatment of certain types of kidney disorders

Dosage

Children: Specific pediatric dosing information is not detailed in the BNF. Refer to the BNF for Children for appropriate dosing based on age and condition.

Adults: Dosage varies based on clinical indication and should be guided by specific treatment protocols. Refer to clinical guidelines for detailed dosing information.

Mechanism of action

Ammonium ions participate in various metabolic pathways, including the biosynthesis of amino acids and nucleotides. It serves as a nitrogen source for organisms, facilitating the synthesis of essential biomolecules. The presence of ammonium can influence pH levels and osmotic balance within cells, thereby affecting cellular functions and enzyme activities.

Pharmacodynamics

Ammonium affects cellular metabolism by acting as a nitrogen donor in the synthesis of organic compounds. Its role in the nitrogen cycle and as a substrate in biochemical pathways allows for the maintenance of cellular functions, including energy production and cellular growth. Alterations in ammonium levels can influence various physiological processes, including neurotransmitter synthesis and energy metabolism.

Pharmacokinetics

Ammonium is readily absorbed and distributed in biological systems. It can be produced endogenously through amino acid metabolism or obtained from dietary sources. The excretion of ammonium primarily occurs through the kidneys, where it is converted to urea for elimination. Ammonium levels are regulated by various mechanisms, including the action of renal tubular cells that either secrete or reabsorb ammonium based on the body's needs.

Indications

• Cough associated with respiratory tract infections
• Acid-base disorders
• Edema management

Dosage

Children: Refer to the BNF for Children for appropriate paediatric dosing guidelines based on age and condition.

Adults: Refer to the BNF for specific adult dosing guidelines as they depend on the indication and clinical context.

Mechanism of action

Ammonium chloride increases acidity by raising hydrogen ion concentrations. It dissociates into ammonium and chloride ions; the ammonium is converted to urea in the liver, releasing hydrogen ions that lower pH. The chloride ions displace bicarbonate in extracellular fluid, leading to acidosis and increased renal excretion of electrolytes and water, resulting in fluid mobilization.

Pharmacodynamics

Ammonium chloride acts as a systemic acidifier, facilitating the excretion of chloride and sodium, while also increasing the acidity of body fluids. The conversion of ammonium to urea in the liver with the release of hydrogen ions contributes to a decrease in blood pH, affecting acid-base balance in the body.

Pharmacokinetics

Ammonium chloride is absorbed from the gastrointestinal tract and metabolized in the liver, where it is converted to urea. The dissociated ions impact renal function, leading to increased excretion of sodium, potassium, and water. The elimination half-life and specific metabolism details are not explicitly defined.

Adverse effects

• Nausea
• Vomiting
• Abdominal pain
• Diarrhea
• Dizziness
• Headache

Interactions

• Antacids may reduce the effectiveness of ammonium chloride
• Potassium-sparing diuretics may increase the risk of hyperkalemia

Precautions

• Use with caution in patients with renal impairment
• Monitor electrolyte levels during prolonged therapy
• Consider potential for acidosis in patients with liver disease

Pregnancy

Ammonium chloride should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus. Consult a healthcare provider for individualized advice.

Breast-feeding

Ammonium chloride is excreted in breast milk. Use caution and consult a healthcare provider if breastfeeding.

Storage

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

Formulations

• Oral solution
• Powder for oral solution

Indications

• Chronic bronchitis
• Asthma
• Bronchiectasis
• Pneumonia
• Respiratory tract infections with productive cough

Dosage

Children: Refer to the BNF for Children for specific paediatric dosing recommendations.

Adults: Refer to the BNF for specific dosing information.

Mechanism of action

Bromhexine aids in mucus clearance by reducing the viscosity of mucus and activating the ciliary epithelium, allowing secretions to be expelled from the respiratory tract. Additionally, bromhexine has been shown to inhibit the transmembrane serine protease 2 receptor (TMPRSS2), which plays a crucial role in viral respiratory diseases. This inhibition may help in preventing or treating various respiratory illnesses, including COVID-19, by blocking viral entry into cells.

Pharmacodynamics

Bromhexine thins airway secretions, thus improving breathing and alleviating discomfort associated with thick mucus in the airways. Its action is particularly beneficial in respiratory disorders where mucus obstruction is a significant issue.

Pharmacokinetics

Bromhexine is well absorbed after oral administration, with peak plasma concentrations typically reached within 1 to 2 hours. It is metabolized in the liver, primarily to ambroxol, which is its active metabolite. The elimination half-life of bromhexine is approximately 8 to 12 hours, and it is excreted mainly through urine. The pharmacokinetics can be influenced by factors such as liver function and concurrent medications.

Adverse effects

• Gastrointestinal disturbances
• Nausea
• Vomiting
• Diarrhea
• Allergic reactions

Precautions

• Use with caution in patients with peptic ulcer disease
• Monitor patients with asthma or bronchospastic conditions

Pregnancy

Bromhexine should be used during pregnancy only if clearly needed and after careful consideration of the potential benefits and risks.

Breast-feeding

Bromhexine is excreted in breast milk; caution should be exercised when administering to nursing mothers.

Storage

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

Formulations

• Tablets
• Syrup
• Solution for inhalation

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
• Pseudobulbar affect

Dosage

Children: Refer to the BNF for Children for specific dosing information tailored to paediatric patients.

Adults: Refer to the BNF for specific dosing guidelines based on the formulation and clinical context.

Mechanism of action

Dextromethorphan acts as a low-affinity uncompetitive antagonist of NMDA receptors and as an agonist at sigma-1 receptors. It also antagonizes α3/β4 nicotinic receptors. The clinical effects are thought to arise from NMDA receptor blockade and serotonin (5-HT) uptake inhibition, which may lead to increased serotonin receptor stimulation. However, the precise mechanisms by which these actions translate into therapeutic effects remain incompletely understood.

Pharmacodynamics

Dextromethorphan is considered an opioid-like molecule with a moderate therapeutic window, indicating that while it is effective at standard doses, higher doses can lead to intoxication. It has a moderate duration of action, making it suitable for use in cough management. Due to its potential for abuse and risk of intoxication, patients are advised to use it cautiously.

Pharmacokinetics

Dextromethorphan is metabolized primarily in the liver through the cytochrome P450 enzyme system, leading to the formation of its active metabolite, dextrorphan. The pharmacokinetics may be influenced by individual variations in metabolic pathways, which can affect the drug's efficacy and safety profile.

Contra-indications

• Hypersensitivity to dextromethorphan or any of its components
• Concurrent use with monoamine oxidase inhibitors (MAOIs)
• Severe respiratory insufficiency or asthma
• Persistent cough due to smoking, emphysema, or chronic bronchitis

Adverse effects

• Dizziness
• Nausea
• Vomiting
• Drowsiness
• Confusion
• Constipation
• Abdominal discomfort
• Euphoria or dysphoria
• Serotonin syndrome (when used with serotonergic drugs)

Interactions

• May interact with MAOIs, leading to serious side effects
• Potential interactions with other CNS depressants, leading to increased sedation
• May enhance the effects of alcohol
• Can interact with medications that affect serotonin levels, increasing the risk of serotonin syndrome

Precautions

• Use with caution in patients with a history of substance abuse
• Monitor use in patients with hepatic impairment
• Caution advised in patients with a history of seizures
• Should not be used in children under 2 years unless directed by a physician

Pregnancy

Dextromethorphan should be used during pregnancy only if clearly needed. Consult a healthcare provider for advice.

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
• Capsules
• Lozenges

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

Ammonium chloride increases acidity by increasing the amount of hydrogen ion concentrations. Ammonium chloride can be used as an expectorant due to its irritative action on the bronchial mucosa. This effect causes the production of respiratory tract fluid which in order facilitates the effective cough. The acid-forming properties of ammonium chloride result from dissociation of the salt to an ammonium cation and a chloride anion. In patients with normal hepatic function, the ammonium cation is converted to urea by the liver and a hydrogen cation is released which reacts with a bicarbonate ion to form water and carbon dioxide. The chloride anion combines with fixed bases in the extracellular fluid, thereby reducing the alkaline reserve of the body. The net result is the displacement of bicarbonate ions by chloride anions. The displacement of bicarbonate by chloride alters the bicarbonate:carbonic acid ratio if the body and acidosis results. The increased chloride concentration in the extracellular fluid produces an increased load to the renal tubules and appreciable amounts of chloride anions escape reabsorption. These anions are excreted along with cations and water. Sodium is the principal cation excreted; however, potassium excretion may also be increased to some degree. By increasing the excretion of both extracellular electrolytes and water, ammonium chloride causes a net loss of extracellular fluid and promotes the mobilization of edema fluid.

Pharmacodynamics

Systemic acidifier. In liver ammonium chloride is converted into urea with the liberation of hydrogen ions ( which lowers the pH) and chloride.

Mechanism of action

Inflammation of the airways, increased mucus secretion, and altered mucociliary clearance are the hallmarks of various diseases of the respiratory tract. Mucus clearance is necessary for lung health; bromhexine aids in mucus clearance by reducing the viscosity of mucus and activating the ciliary epithelium, allowing secretions to be expelled from the respiratory tract. Recent have studies have demonstrated that bromhexine inhibits the transmembrane serine protease 2 receptor (TMPRSS2) in humans. Activation of TMPRSS2 plays an important role in viral respiratory diseases such as influenza A and Middle East Respiratory Syndrome (MERS). Inhibition of receptor activation and viral entry by bromhexine may be effective in preventing or treating various respiratory illnesses, including COVID-19. In vitro studies have suggested the action of ambroxol (a metabolite of bromhexine) on the angiogensin-converting enzyme receptor 2 (ACE2), prevents entry of the viral envelope-anchored spike glycoprotein of SARS-Cov-2 into alveolar cells or increases the secretion of surfactant, preventing viral entry.

Pharmacodynamics

Bromhexine thins airway secretions, improving breathing and discomfort associated with thick mucus in airways associated with a variety of respiratory conditions.

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

Dextromethorphan is a low-affinity uncompetitive NMDA antagonist and sigma-1 receptor agonist. It is also an antagonist of α3/β4 nicotinic receptors. However, the mechanism by which dextromethorphan's receptor agonism and antagonism translate to a clinical effect is not well understood. Dextromethorphan (DXM) is the dextro isomer of levomethorphan, a semisynthetic morphine derivative. Although structurally similar to other /CNS depressants/, DXM does not act as a mu receptor opioid (eg, morphine, heroin). DXM and its metabolite, dextrorphan, act as potent blockers of the N-methyl-d-aspartate (NMDA) receptor. Amantadine and dextromethorphan suppress levodopa (L-DOPA)-induced dyskinesia (LID) in patients with Parkinson's disease (PD) and abnormal involuntary movements (AIMs) in the unilateral 6-hydroxydopamine (6-OHDA) rat model. These effects have been attributed to N-methyl-d-aspartate (NMDA) antagonism. However, amantadine and dextromethorphan are also thought to block serotonin (5-HT) uptake and cause 5-HT overflow, leading to stimulation of 5-HT(1A) receptors, which has been shown to reduce LID. We undertook a study in 6-OHDA rats to determine whether the anti-dyskinetic effects of these two compounds are mediated by NMDA antagonism and/or 5-HT(1A) agonism. In addition, we assessed the sensorimotor effects of these drugs using the Vibrissae-Stimulated Forelimb Placement and Cylinder tests. Our data show that the AIM-suppressing effect of amantadine was not affected by the 5-HT(1A) antagonist WAY-100635, but was partially reversed by the NMDA agonist d-cycloserine. Conversely, the AIM-suppressing effect of dextromethorphan was prevented by WAY-100635 but not by d-cycloserine. Neither amantadine nor dextromethorphan affected the therapeutic effects of L-DOPA in sensorimotor tests. We conclude that the anti-dyskinetic effect of amantadine is partially dependent on NMDA antagonism, while dextromethorphan suppresses AIMs via indirect 5-HT(1A) agonism. Combined with previous work from our group, our results support the investigation of 5-HT(1A) agonists as pharmacotherapies for LID in PD patients. Dextromethorphan (DM) is a dextrorotatory morphinan and an over-the-counter non-opioid cough suppressant. We have previously shown that DM protects against LPS-induced dopaminergic neurodegeneration through inhibition of microglia activation. Here, we investigated protective effects of DM against endotoxin shock induced by lipopolysaccharide/d-galactosamine (LPS/GalN) in mice and the mechanism underlying its protective effect. Mice were given multiple injections of DM (12.5 mg/kg, s.c.) 30 min before and 2, 4 hr after an injection of LPS/GalN (20 ug/700 mg/kg). DM administration decreased LPS/GalN-induced mortality and hepatotoxicity, as evidenced by increased survival rate, decreased serum alanine aminotransferase activity and improved pathology. Furthermore, DM was also effective when it was given 30 min after LPS/GalN injection. The protection was likely associated with reduced serum and liver tumor necrosis factor alpha (TNF-alpha) levels. DM also attenuated production of superoxide and intracellular reactive oxygen species in Kupffer cells and neutrophils. Real-time RT-PCR analysis revealed that DM administration suppressed the expression of a variety of inflammation-related genes such as macrophage inflammatory protein-2, CXC chemokine, thrombospondin-1, intercellular adhesion molecular-1 and interleukin-6. DM also decreased the expression of genes related to cell-death pathways, such as the DNA damage protein genes GADD45 and GADD153. In summary, DM is effective in protecting mice against LPS/GalN-induced hepatotoxicity, and the mechanism is likely through a faster TNF-alpha clearance, and decrease of superoxide production and inflammation and cell-death related components. This study not only extends neuroprotective effect of DM, but also suggests that DM may be a novel compound for the therapeutic intervention for sepsis. /The

Pharmacodynamics

Dextromethorphan is an opioid-like molecule indicated in combination with other medication in the treatment of coughs and pseudobulbar affect. It has a moderate therapeutic window, as intoxication can occur at higher doses. Dextromethorphan has a moderate duration of action. Patients should be counselled regarding the risk of intoxication.