PHARMACHOLOGY OF WOUND

ByNoor Izuani Binti Giban

2010400878

WOUND HEALING A complex integrated sequence of

cellular, physiologic, and biochemical events initiated by the stimulus of injury to tissue

In wound healing,the same events, in the same order, occur in every healing process regardless of the tissue type or the inciting injury.

Principles of Wound Healing

Inflammatory Stage Characterized by redness, heat,

pain and swelling Last approximately 4 to 5 days Initiates the healing process by

stabilizing the wound through platelet activity that stops bleeding & triggers the immune response

Principles of Wound Healing

Inflammatory Stage Within 24 hours of the initial injury,

neutrophils, monocytes and macrophages are on the scene to control bacterial growth and remove dead tissue

Characteristic red color and warmth is caused by the capillary blood system increasing circulation & laying foundation for epithelial growth

Principles of Wound Healing

Proliferation Stage Begins within 24 hours of the initial

injury and may continue for up to 21 days

It is characterized by three events: Epithelialization Granulation Collagen synthesis

Principles of Wound Healing

Granulation Formation of new capillaries that

generate and feed new tissue

Granulation tissue is the beefy red tissue that bleeds easily

Principles of Wound Healing

Epitheliazation Formation of an epithelial layer that seals

and protects the wound from bacteria and fluid loss

It is essential to have a moist environment to foster growth of this layer

It is a very fragile layer that can be easily destroyed with aggressive wound irrigation or cleansing of the involved area

Principles of Wound Healing

Collagen Synthesis Creates a support matrix for the

new tissue that provides it with its’ strength

Oxygen, iron, vitamin C, zinc, magnesium & protein are vital for collagen synthesis

This stage is the actual rebuilding and is influenced by the overall patient condition of the wound bed

Principles of Wound Healing

Differentiation or Maturation

Final stage of wound healing Begins around day 21 and may

continue for up to 2 years Collagen synthesis continues with

eventual closure of the wound and increase in tensile strength

Tensile strength reaches only about 80% of pre-injury strength

Systemic Factors that affect Wound Healing Nutritional Status Vascular Status Metabolic Factors Immunological Factors Age Medications (Steroids, etc) Genetic

The Local Factors Necrotic tissue and foreign bodies Drying of a wound Microorganisms Trauma (pressure, shearing, friction) Fibrin Oxygen Edema

The Growth Factors Platelet-derived growth factor

(PDGF), transforming Growth Factor(TGF), Epidermal growth factor (EGF), macrophage-derived growth factor (MDGF), tumor necrosis factor (TNF), growth inhibitory factor,insulin growth factor I and II, nerve growth factor (NGF), Interleukins.

Drugs Cytotoxic drugs Immunosuppressants NSAIDS Corticosteroids Antiseptics Local anesthetics

Agents that affect healing process

PROHEALERS- Platelet-derived growth factor- Epidermal growth factor- Fibroblast growth factor- Thrombin- Botropase - Vitamin A,Vitamin C- Insulin growth factor- Zinc- Placental extract- others

Agents that affect healing process

ANTIHEALERS- Anticancer agents- Immunosuppressants- NSAIDs- Glucocorticoids- Vitamin E- Semicarbazide- Transforming growth factor-B- Progesterone- Potasium permanganate- Penicillamine- Lathyrogens

Wound healing can be stimulated by PDGF,FGF and EGF.

Modern wound healing research has recognized the wound healingstimulant actions of macrophage-derived growth factor, tumor necrosis factor,insulin likegrowth factor,nerve growth factor and some of the interleukins.

Vitamin A maintains the epithelial integrity and counteracts the wound healing suppressants actions of cytotoxic drugs like cyclophosphamide.

Pyridoxine and thiamine deficiency affect collagen organization and the wound strength.

Ascorbic acid is essential for hydroxylation of proline and lysine in collagen synthesis.

Vitamin D as a potent regulator of cell growth and differentiationinteracts with hemopoietic, immune and skin cells. This will affect wound healing by multiple ways.

Vitamin E is known to affect collagen synthesis.

Steroidal and non-steroidal antiinflammatory drugs supress wound healing.

Zinc or copper complexing of NSAIDs has knocked out the antihealing effects of NSAIDs.

What regulates wound repair?

- Transforming growth factor-B (TGF-B) functions as a ‘pan regulin’ of tissue repair.

- Overproduction of TGF-B has been implicated a causative factor in lung fibrosis,hepatic cirrhosis, bleomycin-induced lung fibrosis and cardiac fibrosis after infarction.

Wound Dressing Sterile bulky gauze wound dressing is commonly

employed. Often, antibiotic impregnated dressings, wet

dressings and dry dressings have also been used. Petroleum-impregnated fine mesh gauze dressing

is superior to wet dressing. Wet dressing promotes re-epithelialization. Antibiotics used along with wound dressings do interfere with the process of wound healing.

Various ointment bases used for wound application interfere with wound repair.

Exercise and Wound Healing

Exercise increases the expression of Mechanogrowth factor has an important role in local tissue repair and remodeling.

When the wound is large,the type of dressing employed may offer obstacle to exercise.

Exercise may increase blood supply to peripheral wound.

The impact of increased blood flow to wound and wound dressing pressure during exercise are likely to disturb texture of wound tissue.

As a result, the strength of wound scar may be reduced and the healed tissue resilience may be poor. This is source of concern because wound dehiscence may occur eventually leading to incisional hernia.

Diabetic and wound Wound complication are common. Surgical wound debridement, antibiotics, proper

hormonal glycemic control and topical formulations have been used for diabetic ulcer wounds.

aerobic exercise can maintain and restore health by reducing chronic inflammation.Exercise can also help reduce some of the risk factors for diabetic foot ulcers via weight loss and improvements in blood glucose, PAD, heart disease and high serum cholesterol and triglycerides

KV Ramesh and KA Shenoy, pharmacology for physiotherapist, Jaypee (2005):267-292

Dorland's Pocket Medical Dictionary 27th Edition

http://www.livestrong.com/article/468915-how-does-exercise-affect-patients-with-diabetic-wounds/

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