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Pharmacology

Warfarin (Coumadin):

  • The most common oral anticoagulant.
  • It is only active in vivo.
  • Warfarin is almost completely bound to plasma proteins. -96% to 98% bound.
  • Warfarin is metabolized by the liver and excreted in the urine.
  • Coumarin anticoagulants pass the placental barrier and are secreted into the maternal milk.
  • Newborn infants are more sensitive to oral anticoagulants than are adults because of lower vitamin K levels and lower rates of metabolism.
  • Bleeding is the most common side effect and occurs most often from the mucous membranes of the gastrointestinal tract and the genitourinary tract.

Oral anticoagulants are contraindicated in:

• Conditions where active bleeding must be avoided, Vitamin K deficiency and severe

hepatic or renal disease, and where intensive salicylate therapy is required.

Balanced Anesthesia
A barbiturate, narcotic analgesic agent, neuromuscular blocking agent, nitrous oxide and one of the more potent inhalation anesthetic.

Sulfonylureas

1st generation
tolbutamide
chlorpropamide

2nd generation

glyburide
glimepiride
glipizide

Mechanism

glucose normally triggers insulin release from pancreatic β cells by increasing intracellular ATP
→ closes K+ channels → depolarization → ↑ Ca2+ influx → insulin release

sulfonylureas mimic action of glucose by closing K+ channels in pancreatic β cells 
→ depolarization → ↑ Ca2+ influx → insulin release

its use results in

↓ glucagon release
↑ insulin sensitivity in muscle and liver

Clinical use

type II DM

stimulates release of endogenous insulin 
cannot be used in type I DM due to complete lack of islet function

Toxicity

first generation

disulfiram-like effects
especially chlorpropamide

second generation

hypoglycemia
weight gain

Immunosuppressive antibodies can be classified mainly into monoclonal and polyclonal antibodies, targeting specific components of the immune system.

  1. Monoclonal Antibodies:

    • Basiliximab: Targets the IL-2 receptor on T cells, inhibiting T-cell activation. It is FDA approved for use in renal transplantation to prevent acute rejection.

    • Alemtuzumab: Targets CD52, a protein found on the surface of mature lymphocytes. It is used for treating chronic lymphocytic leukemia and as an induction agent in kidney transplantation.

    • Rituximab: Targets CD20 on B cells, leading to B-cell depletion. It is used in various conditions, including non-Hodgkin lymphoma and rheumatoid arthritis.

    • Daclizumab: Targets the IL-2 receptor (CD25) and is used in renal transplantation to prevent acute rejection.

    • Eculizumab: Targets complement component C5, inhibiting the complement cascade. It is used in conditions like paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome.

  2. Polyclonal Antibodies:

    • Rabbit Antithymocyte Globulin (rATG): A polyclonal antibody that targets multiple T-cell surface markers, leading to T-cell depletion. It is used as an induction agent in kidney transplantation and for treating acute rejection.

    • Equine Antithymocyte Globulin (eATG): Similar to rATG, it targets T cells and is used in transplantation settings.

  3. Mechanisms of Action:

    • Depletion of Immune Cells: Many antibodies work by depleting specific immune cell populations (e.g., T cells or B cells) to reduce the immune response against transplanted organs or in autoimmune diseases.

    • Blocking Activation Signals: Some antibodies block key receptors involved in T-cell activation, preventing the immune response from being initiated.

    • Inhibition of Complement Activation: Antibodies like eculizumab inhibit the complement system, which can contribute to tissue damage in antibody-mediated rejection.

  4. Clinical Applications:

    • Organ Transplantation: Antibodies are commonly used to prevent rejection in kidney, liver, and heart transplants.

    • Autoimmune Diseases: They are also used in treating conditions like rheumatoid arthritis, lupus, and multiple sclerosis.

  5. Potential Side Effects:

    • Infections: Due to immune suppression, patients are at increased risk of infections.
    • Allergic Reactions: Some patients may experience allergic reactions to antibody therapies.
    • Infusion Reactions: These can occur during the administration of monoclonal antibodies, leading to symptoms like fever, chills, and hypotension.

Selective serotonin reuptake inhibitors (SSRIs)

e.g. fluoxetine, paroxetine, citalopram, and sertraline
- Most commonly used antidepressant category
- Less likely to cause anticholinergic side effects
- Relatively safest antidepressant group in overdose
- Selectively inhibits reuptake of serotonin(5-HT)

Mode of Action;
- Well absorbed when given orally
- Plasma half-lives of 18-24 h allowing once daily dosagedaily dosage
- Metabolised through CYP450 system and most SSRIs inhibit some CYP isoforms
- Therapeutic effect is delayed for 2-4 weeks

ADVERSE DRUG REACTIONS

- Insomnia, increased anxiety, irritability
- Decreased libido
- Erectile dysfunction, anorgasmia, and ejaculatory delay
- Bleeding disorders
- Withdrawal syndrome

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).

SGLT-2 Inhibitors

canagliflozin
empagliflozin

Mechanism

glucose is reabsorbed in the proximal tubule of the nephron by the sodium-glucose cotransporter 2 (SGLT2)
SGLT2-inhibitors lower serum glucose by increasing urinary glucose excretion
the mechanism of action is independent of insulin secretion or action

Clinical use

type II DM

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