NEET MDS Lessons
Pharmacology
Immunosuppressive drugs are essential in managing various medical conditions, particularly in preventing organ transplant rejection and treating autoimmune diseases. They can be classified into five main groups:
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Glucocorticoids: These are steroid hormones that reduce inflammation and suppress the immune response. They work by inhibiting the production of inflammatory cytokines and reducing the proliferation of immune cells. Common glucocorticoids include prednisone and dexamethasone. Their effects include:
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Mechanism of Action: Glucocorticoids inhibit the expression of genes coding for pro-inflammatory cytokines (e.g., IL-1, IL-2, TNF-α).
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Clinical Uses: They are used in conditions like rheumatoid arthritis, lupus, and to prevent transplant rejection.
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Side Effects: Long-term use can lead to osteoporosis, weight gain, diabetes, and increased risk of infections.
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Cytostatic Drugs: These agents inhibit cell division and are often used in cancer treatment as well as in autoimmune diseases. They include:
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Examples: Cyclophosphamide, azathioprine, and methotrexate.
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Mechanism of Action: They interfere with DNA synthesis and cell proliferation, particularly affecting rapidly dividing cells.
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Clinical Uses: Effective in treating cancers, systemic lupus erythematosus, and other autoimmune disorders.
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Side Effects: Can cause bone marrow suppression, leading to increased risk of infections and anemia.
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Antibodies: This group includes monoclonal and polyclonal antibodies that target specific components of the immune system.
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Types:
- Monoclonal Antibodies: Such as basiliximab and daclizumab, which target the IL-2 receptor to prevent T-cell activation.
- Polyclonal Antibodies: These are derived from multiple B-cell clones and can broadly suppress immune responses.
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Clinical Uses: Used in organ transplantation and to treat autoimmune diseases.
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Side Effects: Risk of infections and allergic reactions due to immune suppression.
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Drugs Acting on Immunophilins: These drugs modulate immune responses by binding to immunophilins, which are proteins that assist in the folding of other proteins.
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Examples: Cyclosporine and tacrolimus.
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Mechanism of Action: They inhibit calcineurin, a phosphatase involved in T-cell activation, thereby reducing the production of IL-2.
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Clinical Uses: Primarily used in organ transplantation to prevent rejection.
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Side Effects: Nephrotoxicity, hypertension, and increased risk of infections.
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Other Drugs: This category includes various agents that do not fit neatly into the other classifications but still have immunosuppressive effects.
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Examples: Mycophenolate mofetil and sirolimus.
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Mechanism of Action: Mycophenolate inhibits lymphocyte proliferation by blocking purine synthesis, while sirolimus inhibits mTOR, affecting T-cell activation and proliferation.
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Clinical Uses: Used in transplant patients and in some autoimmune diseases.
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Side Effects: Gastrointestinal disturbances, increased risk of infections, and potential for malignancies.
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Needle selection
Nerve blocks:
Inferior alveolar- 25 G short (LLU technique)
PSA- 25 G short
Mental/Incisive- 25 G short
Palatal- 27/30 G short/ultrashort
Gow-Gates/Akinosi- 25 G long
Infraorbital- 25 G long
Field Block:
ASA 25/27 short
Infiltration:
Infiltration/SP 25/27 short
PDL/Intraosseous
PDL 27/30 short
Intraosseous 30 short/ultrashort
Pharmacology is the study of drugs and the way they interact with living systems. Clinical pharmacology is the study of drugs in humans.
A drug is any chemical that can effect living processes.
Therapeutics: the medical use of drugs.
An ideal drug has several important properties. Three of these properties are of utmost importance: effectiveness, safety and selectivity.
Effectiveness: This is the most important quality that a drug can have. Effectiveness refers to the drug's ability to do what it is supposed to do.
Safety: Although no drug can be totally safe, proper usage can lessen the risks of adverse effects.
Selectivity: A truly selective drug would have no side effects, and would effect only the body process' for which it is designed and given. Therefore, there is no such thing as a selective drug.
Pharmacokinetics: The way the body deals with a drug. Pharmacokinetics is concerned with the processes of absorption, distribution, metabolism and excretion.
Pharmacodynamics: What a drug does to the body.
Pharmacokinetics and pharmacodynamics are two of the processes that determine how a person will respond to a drug. Other factors include how a drug is administered (dose, route, and timing of administration), interactions with other drugs, and individual physiological variables (weight, age, function of body systems).
Pramlintide -Amylin mimetics
Mechanism
synthetic analogue of human amylin that acts in conjunction with insulin
↓ release of glucagon
delays gastric emptying
Clinical use
type I and II DM
PHARMACOLOGY OF LOCAL ANESTHETICS
Characteristics
1. Block axon conduction (nerve impulse) when applied locally in appropriate concentrations.
2. Local anesthetic action must be completely reversible; however, the duration of the anesthetic block should be of sufficient length to allow completion of the planned treatment.
3. Produce minimal local toxic effects such as nerve and muscle damage as well as minimal systemic toxic effects of organ systems such as the cardiovascular and central nervous system.
Nystatin
Candida spp. are sensitive to nystatin.
Uses: Cutaneous, vaginal, mucosal and esophageal infections.
Candida infections can be treated with nystatin.
Cryptococcus is also sensitive to nystatin.
Nystatin is often used as prophylaxis in patients who are at risk for fungal infections, such as AIDS patients with a low CD4+ count and patients receiving chemotherapy.
MOA
nystatin binds to ergosterol, the main component of the fungal cell membrane. When present in sufficient concentrations, it forms a pore in the membrane that leads to K+ leakage and death of the fungus.
Heroin (diacetyl morphine)
Heroin is synthetically derived from the natural opioid alkaloid morphine
Largely owing to its very rapid onset of action and very short half-life, heroin is a popular drug of abuse
It is most effective when used intravenously
Heroin is rapidly deacetylated to 6-monoacetyl morphine and morphine, both of which are active at the mu opioid receptor
More lipid soluble than morphine and about 2½ times more potent. It enters the CNS more readily.