TEXALIN SYRUP

Indications

• Asthma
• Chronic Obstructive Pulmonary Disease (COPD)
• Exacerbation of reversible airways obstruction
• Prevention of exercise-induced bronchospasm
• Uncomplicated premature labor (under specialist supervision)

Dosage

Adults: Initially 2.5 mg 3 times a day for 1–2 weeks, then increased to

Mechanism of action

Terbutaline exerts its effects by selectively stimulating beta-2 adrenergic receptors located in the smooth muscle of the airways. This activation leads to the activation of adenylate cyclase, resulting in increased levels of cyclic AMP (cAMP). Elevated cAMP levels promote relaxation of the bronchial smooth muscle, leading to bronchodilation. Additionally, terbutaline may inhibit the release of mediators from mast cells, reducing bronchoconstriction and inflammation.

Pharmacodynamics

The pharmacodynamic profile of terbutaline includes rapid onset of action, typically within 5 to 15 minutes when inhaled, and a duration of action of approximately 3 to 6 hours. It provides symptomatic relief from bronchospasm associated with asthma and chronic obstructive pulmonary disease (COPD). The drug is also noted for its tocolytic effects, as it can inhibit uterine contractions, making it useful in managing premature labor.

Pharmacokinetics

Terbutaline is well absorbed following inhalation and oral administration, with peak plasma concentrations occurring within 1 to 3 hours. It exhibits a volume of distribution of approximately 3 L/kg, indicating extensive tissue distribution. The drug is metabolized primarily in the liver and has a half-life of about 3 to 5 hours. Terbutaline is excreted mainly in urine, both as unchanged drug and metabolites. Its pharmacokinetic profile may be affected by factors such as age, liver function, and concomitant medications.

Adverse effects

• Tachycardia
• Palpitations
• Tremors
• Headache
• Nausea
• Dizziness
• Hypokalemia
• Hyperglycemia

Interactions

• Beta-blockers may reduce the effectiveness of terbutaline
• Corticosteroids may enhance the effect of terbutaline
• Concomitant use with other sympathomimetics may increase cardiovascular side effects

Precautions

• Use with caution in patients with cardiovascular disorders
• Caution in patients with diabetes due to potential hyperglycemia
• Monitor potassium levels in patients at risk of hypokalemia
• Monitor for paradoxical bronchospasm

Pregnancy

Terbutaline should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Terbutaline 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: 2.5 mg and 5 mg
• Nebuliser solution: 0.5 mg/ml
• Injection: 0.5 mg/1 ml

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

• Expectorant for productive cough
• Relief of cough associated with colds and bronchitis
• Management of respiratory conditions with excessive mucus production

Dosage

Children: Refer to specific dosing guidelines in the BNF for Children.

Adults: Refer to specific dosing guidelines in professional resources or the BNF.

Mechanism of action

Guaifenesin acts by increasing the volume and reducing the viscosity of secretions in the airways, which promotes the clearance of mucus through ciliary action and enhances the expectoration process. This helps to alleviate coughing and facilitates easier breathing.

Pharmacodynamics

The pharmacodynamics of guaifenesin involve its role as a mucolytic agent that alters the properties of mucus. By decreasing the thickness of mucus, it aids in its expulsion from the respiratory tract. This mechanism is particularly beneficial in conditions such as bronchitis, pneumonia, and other respiratory infections where mucus accumulation poses a challenge to breathing.

Pharmacokinetics

Guaifenesin is rapidly absorbed from the gastrointestinal tract, with peak plasma concentrations typically occurring within an hour after administration. It is metabolized primarily in the liver, and its elimination half-life ranges from 1 to 2 hours. The drug is excreted mainly through the kidneys as both unchanged drug and metabolites.

Adverse effects

• Nausea
• Vomiting
• Dizziness
• Headache
• Rash
• Diarrhea

Precautions

• Use with caution in patients with severe renal impairment.
• Ensure adequate hydration during treatment to facilitate mucolytic effect.
• Caution in patients with a history of asthma or bronchospasm.

Pregnancy

Guaifenesin is generally considered safe to use during pregnancy; however, it is advisable to consult a healthcare provider before use.

Breast-feeding

Guaifenesin is excreted in breast milk, but it is generally considered safe for breastfeeding mothers; consult a healthcare provider for personalized advice.

Storage

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

Formulations

• Oral tablets
• Oral syrup
• Extended-release tablets

Indications

• Topical analgesic for muscle and joint pain
• Cough suppressant in cough drops and lozenges
• Relief of minor throat irritation
• Cooling agent in various cosmetic and personal care products

Dosage

Children: Refer to BNF for Children for specific dosing guidelines, as doses may vary based on age and formulation.

Adults: For topical use, apply a thin layer to the affected area not more than 3 to 4 times daily. For cough drops, follow the product-specific instructions as per the formulation.

Mechanism of action

Menthol acts as an agonist for the transient receptor potential subtype M8 (TRPM8), a non-selective cation channel that is activated by cold temperatures. This activation leads to calcium influx in mast cells, inducing the release of histamine, which can trigger allergic responses such as urticaria, asthma, and rhinitis. Menthol's ability to induce histamine release via TRPM8 suggests potential therapeutic applications for TRPM8 antagonists in managing cold- and menthol-induced allergies.

Pharmacodynamics

Menthol produces a cooling effect by stimulating sensory neurons that convey cold sensations. It interacts with TRPM8 channels, leading to the activation of intracellular signaling pathways that can result in vasodilation and increased blood flow to the area of application. This cooling sensation can provide symptomatic relief in conditions characterized by pain or irritation.

Pharmacokinetics

Menthol is absorbed through the skin and mucous membranes, with systemic effects depending on the route of administration. Its bioavailability can vary, and it is metabolized primarily in the liver. The elimination half-life and excretion pathways have not been extensively characterized, but menthol is generally considered to have a rapid onset of action with effects lasting for a few hours.

Adverse effects

• Allergic reactions
• Urticaria
• Asthma
• Rhinitis
• Skin irritation

Precautions

• Use with caution in patients with known allergies to menthol or related compounds
• May exacerbate asthma in sensitive individuals

Pregnancy

There are no well-controlled studies of menthol in pregnant women. Menthol should be used during pregnancy only if clearly needed.

Breast-feeding

Menthol is excreted in breast milk. Caution should be exercised when administering to nursing mothers.

Storage

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

Formulations

• Topical ointment
• Cream
• Liquid

Indications

• Bronchospasm
• Asthma
• Chronic bronchitis
• Emphysema

Dosage

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

Adults: Refer to the BNF for specific dosing guidelines.

Mechanism of action

Terbutaline exerts its effects through selective agonism of beta-2 adrenergic receptors located in the bronchioles. This activation leads to the stimulation of adenylyl cyclase, which increases the levels of intracellular cyclic adenosine monophosphate (cAMP). The rise in cAMP reduces intracellular calcium concentrations, leading to the activation of protein kinase A. This enzyme inactivates myosin light-chain kinase and activates myosin light-chain phosphatase, ultimately resulting in the relaxation of smooth muscle within the bronchioles.

Pharmacodynamics

As a beta-2 adrenergic receptor agonist, terbutaline is indicated for the relief of bronchospasm in conditions such as asthma, chronic bronchitis, and emphysema. It has a rapid onset of action and a relatively short duration of effect, typically requiring administration up to three times daily in its inhaled form. The therapeutic window for terbutaline is wide, making it generally safe within prescribed doses.

Pharmacokinetics

Terbutaline is rapidly absorbed when administered via inhalation, allowing for quick therapeutic action. The drug undergoes extensive first-pass metabolism when taken orally, which may affect its bioavailability. It is primarily metabolized in the liver and has a half-life that supports frequent dosing. Excretion occurs mainly via the kidneys, with metabolites detectable in urine.

Contra-indications

• Hypersensitivity to terbutaline or any of its components
• Severe hypersensitivity to sympathomimetic amines
• Tachyarrhythmias
• Cardiac arrhythmias

Adverse effects

• Tremor
• Tachycardia
• Palpitations
• Headache
• Nausea
• Dizziness
• Muscle cramps
• Hypokalemia

Interactions

• Beta-blockers may reduce the effectiveness of terbutaline
• Concomitant use with other sympathomimetics may increase the risk of cardiovascular side effects
• Monoamine oxidase inhibitors (MAOIs) can potentiate the effects of terbutaline

Precautions

• Use with caution in patients with cardiovascular disorders
• Monitor potassium levels in patients with significant hypokalemia
• Caution in patients with diabetes mellitus as beta agonists may induce hyperglycemia

Pregnancy

Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Category C.

Breast-feeding

Terbutaline is excreted in human milk, and caution should be exercised when administered to a nursing woman.

Storage

Store below 25 degrees Celsius. Protect from light and moisture. Keep out of reach of children.

Formulations

• Inhalation aerosol
• Oral tablets
• Injection

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

Exposure to low temperatures often causes allergic responses or urticaria. Similarly, menthol, a common food additive is also known to cause urticaria, asthma, and rhinitis. However, despite the obvious clinical implications, the molecular mechanisms responsible for inducing allergic responses to low temperatures and menthol have not been determined. Because a non-selective cation channel, transient receptor potential subtype M8 (TRPM8) is activated by cold and menthol, we hypothesized that this channel mediates cold- and menthol-induced histamine release in mast cells. Here, we report that TRPM8 is expressed in the basophilic leukemia mast cell line, RBL-2H3, and that exposure to menthol or low temperatures induced Ca(2+) influx in RBL-2H3 cells, which was reversed by a TRPM8 blocker. Furthermore, menthol, a TRPM8 agonist, induced the dose-dependent release of histamine from RBL-2H3 cells. When TRPM8 transcripts were reduced by siRNA (small interfering RNA), menthol- and cold-induced Ca(2+) influx and histamine release were significantly reduced. In addition, subcutaneous injection of menthol evoked scratching, a typical histamine-induced response which was reversed by a TRPM8 blocker. Thus, our findings indicate that TRPM8 mediates the menthol- and cold-induced allergic responses of mast cells, and suggest that TRPM8 antagonists be viewed as potential treatments for cold- and menthol-induced allergies. /DL-Menthol/ Menthol's characteristic cooling sensation is due, in part, to the activation of sensory neurons generally termed transient receptor potential (TRP) channels, in particular transient receptor potential melastatin family member 8 (TRPM8) and transient receptor potential subfamily A, member 1 (TRPA1). Menthol acts upon TRPM8 receptors by rapidly increasing intracellular calcium and mobilizing calcium flux through the channels to induce cold response signals at the application site. Aside from its cold-inducing sensation capabilities, menthol exhibits cytotoxic effects in cancer cells, induces reduction in malignant cell growth, and engages in synergistic excitation of GABA receptors and sodium ion channels resulting in analgesia. /DL-Menthol/ In recent years, the transient receptor potential melastatin member 8 (TRPM8) channel has emerged as a promising prognostic marker and putative therapeutic target in prostate cancer. We have found that forced overexpression of TRPM8 in PC-3 cells can inhibit the cell proliferation and motility probably through the TRPM8 activation. In this study, we aimed to investigate whether activating the TRPM8 channel by its selective agonist menthol can inhibit the proliferation and motility of androgen-independent prostate cancer (AIPC) with remarkable expression of TRPM8. Menthol is a naturally occurring compound, which has been widely used in cosmetics and pharmaceutical products, and also as flavoring in food. DU145 cells are androgen-independent but have a remarkable expression of TRPM8. The demonstration of the existence of TRPM8 and the absence of TRPA1 in DU145 cells provided the foundation for the following experiments, because both TRPM8 and TRPA1 are molecular targets of menthol. The outcome of MTT assay indicated that menthol inhibited the cell growth (p < 0.01). Cell cycle distribution and scratch assay analysis revealed that menthol induced cell cycle arrest at the G(0)/G(1) phase (p < 0.01). Furthermore, menthol inhibited the migration of DU145 cells by downregulating the focal-adhesion kinase. So it suggests that the activation of the existing TRPM8 channels may serve as a potential and pragmatic treatment for those AIPC with remarkable expression of TRPM8, and menthol is a useful compound for future development as an anticancer agent. /DL-Menthol/

Mechanism of action

Terbutaline is a selective beta-2 adrenergic receptor agonist. Agonism of these receptors in bronchioles activates adenylyl cyclase, increasing intracellular cyclic adenosine monophosphate (cAMP). Increased cAMP decreases intracellular calcium, activating protein kinase A, inactivating myosin light-chain kinase, activating myosin light-chain phosphatase, and finally relaxing smooth muscle in the bronchiole.

Pharmacodynamics

Terbutaline is a beta-2 adrenergic receptor agonist indicated to treat reversibly bronchospasm in asthmatic patients with bronchitis and emphysema. It has a short duration as the inhaled form is taken up to three times daily, and the therapeutic window is wide.