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Pharmacology - NEETMDS- courses
NEET MDS Lessons
Pharmacology

Neurolept Anesthesia
An antipsychotic agent such as droperidol plus an opiate analgesic agent such as fentanyl or sufentanil. This latter agent is approximately eight to ten times more potent than fentanyl.

Carbapenems: Broadest spectrum of beta-lactam antibiotics.

imipenem with cilastatin

meropenem

ertapenem

Monobactams: Unlike other beta-lactams, there is no fused ring attached to beta-lactam nucleus. Thus, there is less probability of cross-sensitivity reactions.

aztreonam

Beta-lactamase Inhibitors No antimicrobial activity. Their sole purpose is to prevent the inactivation of beta-lactam antibiotics by beta-lactamases, and as such, they are co-administered with beta-lactam antibiotics.

clavulanic acid

tazobactam

sulbactam

Heparin:

  • Inhibits blood coagulation by forming complexes with an α2-globulin (Antithrombin III) and each of the activated proteases of the coagulation cascade (Kallikrein, XIIa, XIa, IXa, Xa, and Thrombin). After formation of the heparin-ATIII-coagulation factor, heparin is released and becomes available again to bind to free ATIII.
  • Blocks conversion of Prothrombin to Thrombin and thus inhibits the synthesis of Fibrin from Fibrinogen.
  • Inhibits platelet function and increases vascular permeability. May induce moderate to severe thrombocytopenia.
  • Is prescribed on a “unit” basis.
  • Heparin is not effective after oral administration and is generally administered by intravenous or subcutaneous injection. Intramuscular injections should be avoided.
  • Heparin does not cross the placenta and does not pass into the maternal milk.
  • is contraindicated in any situation where active bleeding must be avoided.

Ulcerative lesions, intracranial hemorrhage, etc.

Overdosage:

• Simple withdrawal.

• Protamine sulfate: Highly basic peptide that binds heparin and thus neutralizes its effects.

Osmotic diuretics

An osmotic diuretic is a type of diuretic that inhibits reabsorption of water and sodium. They are pharmacologically inert substances that are given intravenously. They increase the osmolarity of blood and renal filtrate.

Mechanism(s) of Action

1.    Reduce tissue fluid (edema) 
2.    Reflex cardiovascular effect by osmotic retention of fluid within vascular space which increases blood volume (contraindicated with Congestive heart failure) 
3.    Diuretic effect

o    Makes H2O reabsorption far more difficult for tubular segments insufficient Na & H2O capacity in distal segments
o    Increased intramedullary blood flow (washout)
o    Incomplete sodium recapture (asc. loop). this is indirect inhibition of Na reabsorption (Na stays in tubule because water stays) 
o    Net diuretic effect: 
    Tubular concentration of sodium decreases 
    Total amount of sodium lost amount increases 
    GFR unchanged or slightly increased

Toxicity

Circulatory overload, dilutional hyponatremia,  Hyperkalemia, edema, skin necrosis

Agents
Mannitol

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:

  1. 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:

    • Mechanism of Action: Glucocorticoids inhibit the expression of genes coding for pro-inflammatory cytokines (e.g., IL-1, IL-2, TNF-α).

    • Clinical Uses: They are used in conditions like rheumatoid arthritis, lupus, and to prevent transplant rejection.

    • Side Effects: Long-term use can lead to osteoporosis, weight gain, diabetes, and increased risk of infections.

  2. Cytostatic Drugs: These agents inhibit cell division and are often used in cancer treatment as well as in autoimmune diseases. They include:

    • Examples: Cyclophosphamide, azathioprine, and methotrexate.

    • Mechanism of Action: They interfere with DNA synthesis and cell proliferation, particularly affecting rapidly dividing cells.

    • Clinical Uses: Effective in treating cancers, systemic lupus erythematosus, and other autoimmune disorders.

    • Side Effects: Can cause bone marrow suppression, leading to increased risk of infections and anemia.

  3. Antibodies: This group includes monoclonal and polyclonal antibodies that target specific components of the immune system.

    • 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.
    • Clinical Uses: Used in organ transplantation and to treat autoimmune diseases.

    • Side Effects: Risk of infections and allergic reactions due to immune suppression.

  4. Drugs Acting on Immunophilins: These drugs modulate immune responses by binding to immunophilins, which are proteins that assist in the folding of other proteins.

    • Examples: Cyclosporine and tacrolimus.

    • Mechanism of Action: They inhibit calcineurin, a phosphatase involved in T-cell activation, thereby reducing the production of IL-2.

    • Clinical Uses: Primarily used in organ transplantation to prevent rejection.

    • Side Effects: Nephrotoxicity, hypertension, and increased risk of infections.

  5. Other Drugs: This category includes various agents that do not fit neatly into the other classifications but still have immunosuppressive effects.

    • Examples: Mycophenolate mofetil and sirolimus.

    • Mechanism of Action: Mycophenolate inhibits lymphocyte proliferation by blocking purine synthesis, while sirolimus inhibits mTOR, affecting T-cell activation and proliferation.

    • Clinical Uses: Used in transplant patients and in some autoimmune diseases.

    • Side Effects: Gastrointestinal disturbances, increased risk of infections, and potential for malignancies.

BradyKinin

An endogenous vasodilator occurring in blood vessel walls. 
At least two distinct receptor types, B1 and B2, appear to exist for BradyKinin

Roles of bradykinin:

1) Mediator of inflammation and pain.
2) Regulation of microcirculation.
3) Their production is interrelated with clotting and fibrinolysin systems.
4) Responsible for circulatory change after birth.
5) Involved in shock and some immune reactions.

Benzodiazepines
All metabolites are active sedatives except the final glucuronide product. Elimination half-life varies a great deal from drug to drug.

?-Hydroxylation is a rapid route of metabolism that is unique to triazolam, midazolam, and alprazolam.
This accounts for the very rapid metabolism and short sedative actions of these drugs.

Pharmacological effects of benzodiazepines

- Antianxiety.
- Sedation.
- Anticonvulsant (including drug-induced convulsions).
- Amnesia, especially drugs like triazolam.
- Relax skeletal muscle (act on CNS polysynaptic pathways).

Indications

- IV sedation, (e.g., midazolam, diazepam, lorazepam).
- Antianxiety.
- Sleep induction.
- Anticonvulsant (e.g., diazepam, clonazepam).
- Panic disorders.
- Muscle relaxation.


Adverse effects

- Ataxia, confusion.
- Excessive sedation.
- Amnesia (not a desired effect with daytime sedation).
- Altered sleep patterns (increase stage 2 and decrease stage 4 sleep).

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