Pharmacology of Asthma and Cancer Treatments

Salbutamol (albuterol) is the first-line medication for relieving an acute asthma attack. It's a short-acting beta-2 adrenergic agonist that relaxes the smooth muscles surrounding the airways, opening them up and improving airflow.

The first priority in a severe asthma attack is to provide bronchodilators to relieve airway obstruction and improve airflow. This is followed by addressing inflammation and protecting the airways from further irritation.

Propranolol, a beta-blocker, can worsen asthma symptoms by blocking the effects of beta-2 agonists, which are essential for bronchodilation.

Montelukast is a leukotriene receptor antagonist. It blocks the action of leukotrienes, inflammatory mediators that contribute to airway constriction and inflammation in asthma.

Vinblastine belongs to the mitotic inhibitor family of chemotherapy drugs. It works by interfering with the formation of microtubules, which are essential for cell division. This prevents cancer cells from multiplying.

Tamoxifen is used to treat estrogen receptor (ER)-positive breast cancer. It acts as an antagonist at estrogen receptors, blocking the growth-stimulating effects of estrogen on tumor cells.

Tacrolimus is a calcineurin inhibitor. It suppresses the immune system by inhibiting the activity of calcineurin, a protein involved in T-cell activation.

Leucovorin is administered to protect normal cells from the toxic effects of methotrexate. It acts as a 'rescue' factor, providing a source of tetrahydrofolic acid, which methotrexate inhibits.

Doxorubicin is a chemotherapy drug that can cause irreversible, dose-dependent cardiotoxicity. This means that repeated or high doses can damage the heart, potentially leading to heart failure.

Vinblastine primarily acts in the M phase of the cell cycle, interfering with microtubule formation and preventing cell division. This is why it is often used to treat rapidly dividing cancer cells.

Dexrazoxane is used to help reduce the cardiotoxicity of doxorubicin. It works by capturing the free radical intermediates produced by doxorubicin, protecting the heart from damage.

Methotrexate is an antimetabolite chemotherapy drug that inhibits dihydrofolate reductase, an enzyme essential for the synthesis of DNA and RNA. By blocking this enzyme, methotrexate prevents cancer cells from replicating.

Muromonab-CD3 is a monoclonal antibody that blocks the activation of the T-cell receptor complex. This effectively prevents T-cells from recognizing and attacking the body's own tissues, reducing immune rejection in organ transplantation.

Chemotherapeutic drugs generally follow first-order kinetics, meaning that a certain proportion of the remaining cancer cells are killed with each dose. This results in a gradual decrease in the cancer mass over time.

Tamoxifen is the first-line therapy for treating ER-positive breast cancer. It blocks the action of estrogen on tumor cells, slowing their growth.

Cisplatin is a chemotherapy drug known for its high emetogenic potential, meaning it frequently causes nausea and vomiting. This is a common side effect that can significantly impact patients' quality of life.

Vinca alkaloids, like vinblastine, work by inhibiting the polymerization of tubulins. Tubulins are proteins that make up microtubules, which are essential for cell division.

Etoposide is a chemotherapy drug that inhibits topoisomerase-I, an enzyme involved in DNA replication. By blocking this enzyme, etoposide prevents cancer cells from dividing.

Cyclophosphamide is a chemotherapy drug that can cause hemorrhagic cystitis, a condition characterized by inflammation and bleeding in the bladder.

Antimetabolites exert cytotoxicity in cancer cells because they are structurally similar to endogenous compounds involved in nucleotide synthesis. They interfere with the production of DNA and RNA, preventing cancer cell replication.

Cyclophosphamide, a nitrogen mustard alkylating agent, is metabolized to its active form, which reacts with the guanine base of DNA, interfering with DNA replication and causing cell death.

Cisplatin is known for its dose-related nephrotoxicity, meaning it can damage the kidneys, potentially leading to kidney failure.

Nitrosoureas are chemotherapy drugs that are primarily used to treat brain tumors because they can cross the blood-brain barrier.

The most significant toxicity associated with immunosuppressant drugs is an increased risk of infections. This is because they suppress the immune system, making the body vulnerable to pathogens.

Corticosteroids are used to treat skin diseases like eczema and psoriasis because of their immunosuppressive effects. They suppress inflammation and reduce the immune response in the skin.

Cyclosporine is an immunosuppressant drug that inhibits the production of cytokines, which are signaling molecules involved in immune responses. This makes it effective in preventing organ transplant rejection.

Selective cyclooxygenase-2 inhibitors are a class of drugs known to cause gastric ulcers as a common adverse effect. These NSAIDs specifically target the COX-2 enzyme involved in inflammation, but they can also affect the stomach's protective lining.

Aspirin, a common analgesic, primarily works by inhibiting the cyclooxygenase enzyme. This enzyme is involved in the production of prostaglandins, which contribute to pain and inflammation.

Long-term use of aspirin can lead to gastric ulcers. Aspirin, by inhibiting the COX enzyme, disrupts the protective layer in the stomach, making it more susceptible to ulcers.

Fentanyl is a powerful opioid analgesic that doesn't rely on inhibiting cyclooxygenase. It works by binding to opioid receptors in the central nervous system, reducing pain perception.

While aspirin is known to reduce the risk of thrombosis (blood clotting), it's not directly associated with thrombosis as an adverse effect. Aspirin's primary action is to inhibit platelet aggregation, which prevents clot formation.