Immunosuppressants: Uses and Side Effects

• Immunological system medications address conditions arising from either an overactive or underactive immune response.
• Medication types include immunosuppressants, immunostimulants, drugs targeting allergic reactions, and treatments for autoimmune diseases.

Immunosuppressants

• These medications function by inhibiting or suppressing immune system activity.
• Post-transplant, they are used to prevent organ rejection; they also treat autoimmune conditions like rheumatoid arthritis, multiple sclerosis, and Crohn's.
• Calcineurin inhibitors such as cyclosporine and tacrolimus diminish T-cell activation via inhibiting calcineurin, a protein essential for T-cell activation.
• mTOR inhibitors like sirolimus and everolimus impede the mechanistic target of rapamycin (mTOR), a protein kinase governing cell growth, proliferation, and survival; this action inhibits both T- and B-cell proliferation.
• Antimetabolites like azathioprine and mycophenolate mofetil disrupt DNA and RNA synthesis, thereby inhibiting the proliferation of rapidly dividing immune cells.
• Monoclonal and polyclonal antibodies target specific immune cells or proteins, causing their depletion or inactivation.
• Corticosteroids like prednisone and methylprednisolone have broad immunosuppressive actions by diminishing inflammatory cytokine production and suppressing immune cell function.

Immunostimulants

• These medications enhance the activity of the immune system.
• They address conditions marked by immune system deficiency, such as infections, immunodeficiency disorders, and certain cancers.
• Interferons (e.g., interferon alfa, interferon beta) are cytokines boosting immune cell activity and inhibiting viral replication.
• Colony-stimulating factors (e.g., filgrastim, pegfilgrastim) stimulate white blood cell production, crucial for fighting infections.
• Vaccines stimulate the immune system to generate antibodies and cellular immunity against specific pathogens, thus conferring protection from future infections.
• Adjuvants are vaccine additives that boost the immune response.
• Immunoglobulins confer passive immunity by providing antibodies to individuals who cannot produce them adequately.

Medications for Allergic Reactions

• Allergic reactions are caused by the immune system's overreaction to harmless substances (allergens).
• Medications for allergic reactions alleviate symptoms and prevent future reactions.
• Antihistamines like diphenhydramine, loratadine, and cetirizine block histamine receptors, reducing symptoms like itching, sneezing, and runny nose.
• Corticosteroids such as fluticasone and budesonide reduce inflammation in airways and nasal passages, alleviating allergic rhinitis and asthma symptoms.
• Decongestants like pseudoephedrine and phenylephrine constrict blood vessels in nasal passages, reducing nasal congestion.
• Leukotriene receptor antagonists (e.g., montelukast) block leukotrienes, substances that contribute to inflammation and bronchoconstriction in asthma and allergic rhinitis.
• Mast cell stabilizers such as cromolyn prevent histamine and other inflammatory mediator release from mast cells, reducing allergic symptoms.
• Epinephrine treats severe allergic reactions (anaphylaxis) by reversing bronchoconstriction and increasing blood pressure.

Medications for Autoimmune Diseases

• Autoimmune diseases arise when the immune system attacks the body's own tissues.
• Medications for these diseases aim to suppress the immune system and diminish inflammation.
• Nonsteroidal anti-inflammatory drugs (NSAIDs) reduce pain and inflammation.
• Disease-modifying antirheumatic drugs (DMARDs) slow the progression of autoimmune diseases like rheumatoid arthritis.
• Biologic DMARDs like etanercept, infliximab, and adalimumab target specific immune proteins such as TNF-alpha to reduce inflammation and joint damage.
• Immunosuppressants like azathioprine and methotrexate suppress the immune system and reduce inflammation in various autoimmune diseases.
• Corticosteroids like prednisone reduce inflammation and suppress the immune system in autoimmune diseases.