Dextromethorphan hydrobromide

Dextromethorphan Hydrobromide

Dextromethorphan hydrobromide is a medication commonly used as a cough suppressant in over-the-counter cold and cough medicines. It is a synthetic derivative of morphine, but unlike morphine, it does not have analgesic or addictive properties at therapeutic doses. Dextromethorphan is classified as an antitussive, which means it is used to relieve cough.

Pharmacology

Dextromethorphan acts on the central nervous system to suppress the cough reflex. It is an NMDA receptor antagonist and a sigma-1 receptor agonist. At therapeutic doses, it primarily affects the cough center in the medulla oblongata, reducing the urge to cough.

Mechanism of Action

Dextromethorphan works by decreasing the activity of the cough center in the brain. It is believed to exert its effects by binding to and inhibiting the NMDA receptor, which plays a role in the transmission of pain and cough signals. Additionally, dextromethorphan's action on sigma-1 receptors may contribute to its cough-suppressing effects.

Metabolism

Dextromethorphan is metabolized in the liver by the cytochrome P450 enzyme CYP2D6 to dextrorphan, which is an active metabolite. The rate of metabolism can vary significantly between individuals due to genetic polymorphisms in the CYP2D6 enzyme.

Uses

Dextromethorphan is primarily used to treat coughs associated with the common cold, bronchitis, and other respiratory illnesses. It is available in various formulations, including syrups, tablets, and lozenges.

Side Effects

Common side effects of dextromethorphan include dizziness, nausea, and drowsiness. At higher doses, it can cause confusion, excitation, and hallucinations. Abuse of dextromethorphan can lead to serious health issues, including serotonin syndrome and dissociative states.

Abuse Potential

Although dextromethorphan is safe at recommended doses, it has potential for abuse, particularly among adolescents. At high doses, it can produce psychoactive effects, including euphoria and hallucinations, due to its action on the NMDA receptor.

Regulation

In many countries, dextromethorphan is available over-the-counter, but some jurisdictions have imposed age restrictions or require identification for purchase to prevent abuse.

Also see

• Cough suppressant
• NMDA receptor antagonist
• Sigma-1 receptor
• Cytochrome P450
• Serotonin syndrome

Engineered Monoclonal Antibodies

Diagram of engineered monoclonal antibodies

Engineered monoclonal antibodies are a class of biological therapies that are designed to target specific antigens on the surface of cells. These antibodies are produced using recombinant DNA technologies and are used in the treatment of various diseases, including cancer, autoimmune disorders, and infectious diseases.

Structure and Function

Monoclonal antibodies are composed of two identical heavy chains and two identical light chains, forming a Y-shaped molecule. The tips of the "Y" contain the antigen-binding sites, which are highly specific to the target antigen. This specificity allows monoclonal antibodies to bind to their target with high affinity, blocking or modulating the function of the antigen.

Types of Engineered Monoclonal Antibodies

There are several types of engineered monoclonal antibodies, each designed for specific therapeutic purposes:

• Chimeric antibodies: These antibodies are composed of murine (mouse) variable regions and human constant regions. They are less immunogenic than fully murine antibodies.

• Humanized antibodies: These antibodies are mostly human, with only the antigen-binding sites derived from murine sources. This reduces the risk of immune reactions.

• Fully human antibodies: These are entirely human in origin, produced using transgenic mice or phage display technologies.

• Bispecific antibodies: These antibodies are engineered to bind two different antigens simultaneously, offering unique therapeutic mechanisms.

Applications in Medicine

Engineered monoclonal antibodies have revolutionized the treatment of many diseases:

• Cancer therapy: Monoclonal antibodies can target specific tumor antigens, leading to direct tumor cell killing or recruitment of immune cells to attack the tumor.

• Autoimmune diseases: By targeting specific components of the immune system, monoclonal antibodies can reduce inflammation and tissue damage in diseases such as rheumatoid arthritis and multiple sclerosis.

• Infectious diseases: Monoclonal antibodies can neutralize pathogens or their toxins, providing passive immunity or enhancing the host's immune response.

Production

The production of engineered monoclonal antibodies involves several steps:

1. Antigen identification: The target antigen is identified and characterized. 2. Hybridoma technology: B cells from immunized animals are fused with myeloma cells to create hybridomas that produce the desired antibody. 3. Recombinant DNA technology: Genes encoding the antibody are cloned and expressed in suitable host cells, such as Chinese hamster ovary cells. 4. Purification and formulation: The antibodies are purified and formulated for clinical use.

Challenges and Future Directions

While engineered monoclonal antibodies have shown great promise, there are challenges such as high production costs, potential for immune reactions, and the development of resistance. Ongoing research aims to improve antibody design, reduce immunogenicity, and enhance therapeutic efficacy.

Related Pages

• Monoclonal antibody therapy
• Biopharmaceutical
• Immunotherapy
• Hybridoma technology