Exhaustive Guide to Percutaneous Medication Administration

Overview of Percutaneous Administration

• Percutaneous administration refers to the delivery of medications or fluids through the skin or mucous membranes for localized or systemic absorption.

• This route includes various delivery methods:

  • Topical applications (creams, lotions, ointments).

  • Transdermal patches.

  • Inhalations.

  • Mucosal instillations (e.g., eye, ear, or vaginal drops).

• Primary Goal: The primary objective is to achieve therapeutic effects while minimizing systemic side effects.

Characteristics of Topical Dosage Forms: Creams, Lotions, and Ointments

• Creams

  • Defined as semisolid emulsions containing medicinal agents for external application.

  • Key characteristics: Generally non-greasy and can be removed easily with water.

  • Common application: Often used as moisturizing agents.

• Lotions

  • Defined as aqueous (water-based) preparations containing suspended medicinal materials.

  • Key characteristics: Used as soothing agents to protect the skin and relieve rashes or itching; some have a cleansing action.

  • Administration technique: To prevent increased circulation and further itching, lotions should be gently but firmly patted onto the skin rather than rubbed.

  • Important instruction: Shake all lotions thoroughly immediately before application and use sparingly to avoid waste.

• Ointments

  • Defined as semisolid preparations of medicinal substances in an oily base (e.g., lanolin or petrolatum).

  • Key characteristics: Can be applied to skin or mucous membranes; generally cannot be removed easily with water.

  • Function: The oily base helps maintain the medicinal substance in prolonged contact with the skin.

Clinical Procedure for Applying Creams and Ointments

• Pre-application Checks

  • Check the Medication Administration Record (MAR) chart to confirm the correct medication name and dose.

  • Confirm the identity of the person receiving care.

  • Check the label of the tube or tub for accuracy.

  • Check the expiry date and ensure the medication is in good condition (not contaminated).

  • Note the date of opening on the tube or tub; creams should be used within $3$ months of first use or as directed by the label/leaflet.

• Application Steps

  • Wash and dry hands thoroughly before applying gloves.

  • Apply to clean skin: Wash, rinse, and dry the affected area first.

  • Exception: If the skin is very dry or flaking, apply the medication while the skin is still damp.

  • Dispensing:

  • Tubs: Scoop a small amount using a gloved hand or a clean spoon/spatula (do not put hands directly in the tub to prevent infection).

  • Tubes: Squeeze a small amount into the hand.

  • Communication: Inform the patient that the initial application may feel cold.

  • Technique: Apply a small amount gently in the direction of hair growth using a gloved hand. Do not rub vigorously.

  • Steroid-specific: Medicated creams (steroids/ointments) must be applied sparingly and only to affected areas.

  • Emollient-specific: Can usually be applied more plentifully.

  • Disposal and Hygiene: Do not return unused cream to the tub (prevents contamination). Dispose of gloves and perform hand hygiene.

  • Documentation: Document the administration as required.

  • Safety Rule: Never apply a cream prescribed for one person to another person.

Emollient Creams and Infection Control

• Emollients are moisturizing treatments that reduce water loss by covering the skin with a protective film.

• Used for dry or scaly conditions like eczema and psoriasis.

• They often come in large tubes, tubs, or pump dispensers and should be applied frequently throughout the day, even if the skin is improving.

• Application to hairy areas: Follow the direction of hair growth.

• To prevent infection in tubs: Never put hands in the tub; use a clean spoon or spatula to scoop out the cream.

Topical Corticosteroids and the Fingertip Unit (FTU)

• Topical Steroids must be applied very thinly and only as prescribed (typically $1$ or $2$ times daily) to minimize systemic absorption.

• The Fingertip Unit ($1$ FTU) is a standard measure for application thinness:

  • Definition: The distance from the tip of an adult index finger to the first crease of the finger.

  • Coverage: $1$ FTU is sufficient to cover an area twice the size of a flat adult hand (fingers together).

• Recommended FTU Dosages for Adults (Single Application)

  • Genitalia: $0.5$ FTU

  • Per hand: $1$ FTU

  • Face and Neck: $2.5$ FTU

  • Per foot: $2$ FTU

  • Per arm: $3$ FTU

  • Per leg: $6$ FTU

  • Chest and Abdomen: $7$ FTUs

  • Back and Buttocks: $7$ FTUs

Topical Steroid Potency Classification

• Mild: Hydrocortisone ($0.5\%$ or $1\%$).

• Moderate: Clobetasone butyrate ($0.05\%$); Trimovate (combined with antimicrobial).

• Potent: Betamethasone ($0.1\%$); Betnovate C (with antimicrobial); Fucidin H (Hydrocortisone with antimicrobial).

• Very Potent: Clobetasol propionate ($0.05\%$); Dermovate NN (with antimicrobial).

Nitroglycerin Ointment Administration

• Overview: A topical nitrate used to prevent and relieve angina pectoris (chest pain). It is systemically absorbed through the skin into the bloodstream.

• Composition: Commonly available as Nitroglycerin USP $0.2\%\,w/w$ in an ointment base ($30\,g$ tube).

• Mechanism of Action:

  • Nitroglycerin is converted into Nitric Oxide ($NO$) in vascular smooth muscle cells.

  • Results in relaxation of vascular smooth muscle, causing: Predominant vasodilation of veins, reduced venous return (preload), reduced myocardial oxygen demand, and mild dilation of coronary arteries.

• Contraindications:

  • Allergy to nitrates, severe hypotension, cardiogenic shock, severe anemia, increased intracranial pressure, recent head injury, constrictive pericarditis, or hypertrophic obstructive cardiomyopathy.

  • PDE-5 Inhibitors: Concurrent use with Sildenafil, Tadalafil, or Vardenafil is a medical emergency due to the risk of profound hypotension.

• Administration Procedure:

  • Safety: Always wear gloves (the medication is absorbed through the skin; failure to do so causes headaches/dizziness for the nurse).

  • Assessment: Verify vital signs (BP, HR); do not administer if BP is below parameters. Assess chest pain intensity ($0-10$ scale).

  • Removal of Old Dose: Wipe off all old ointment before applying a new dose to prevent overdose.

  • Site Selection: Clean, dry, hairless, intact area (upper chest, upper arm, shoulder, or back). Rotate sites.

  • Measurement: Squeeze the prescribed amount (ordered in inches or centimeters) onto the applicator paper.

  • Application: Place the paper against the skin. Do NOT rub or massage the ointment into the skin, as this alters absorption.

  • Securement: Tape the paper in place or use a transparent dressing.

• Adverse Effects: Headache, orthostatic hypotension, flushing, reflex tachycardia, and skin irritation.

Transdermal Patch Administration

• Definition: A medicated adhesive patch delivering medication through the skin into the bloodstream over a prolonged period ($1$ to $7$ days).

• Examples: Nitroglycerin, Fentanyl, Nicotine, Clonidine, Rivastigmine, Hormone Replacement Therapy, Tulobuterol.

• Mechanisms:

  • Membrane-controlled: Porous membrane controls drug flow from a liquid/gel reservoir.

  • Matrix: Medicine is embedded in adhesive layers; body heat melts it for absorption.

• System Layers:

  1. Occlusive backing membrane (protection).

  2. Drug reservoir or matrix.

  3. Release liner (removed before use).

  4. Adhesive layer (peripheral or face adhesive).

• Advantages vs. Disadvantages:

  • Advantages: Avoids GIT absorption issues, avoids first-pass hepatic metabolism, improved compliance, maintains therapeutic levels for days, allows rapid termination.

  • Disadvantages: Daily dose limit ($10\,mg$ maximum), local irritation, high blood level requirements are unsuitable, sweat/heat affects adhesion, expensive.

• Nursing Responsibilities and Steps:

  • Patient Safety: Avoid heat sources (heating pads, hot tubs, direct sun) which increase absorption and cause toxicity.

  • Removal: Peel off the old patch, fold it in half with sticky sides together, and dispose of it in a closed trash container.

  • Site Preparation: Select a clean, hairless, intact area. Clean with warm water or clear non-lotion soap. Dry completely—never apply to wet skin.

  • Application: Peel the liner (avoiding the adhesive with fingers). Press firmly with the palm for $10$ to $30$ seconds to ensure adhesion.

  • Caveat: Do not cut a patch unless explicitly stated by the manufacturer.

Wound Dressings: Types and Applications

• Gauze Dressing: Absorbent for minor wounds and basic protection.

• Non-adherent Dressing (e.g., Telfa): For delicate wounds/burns; prevents sticking.

• Transparent Film (e.g., OpSite, Tegaderm): Waterproof; allows wound observation; used for superficial wounds or IV sites.

• Hydrocolloid (e.g., DuoDERM): Gel-forming; maintains a moist environment for pressure ulcers (moderate exudate).

• Hydrogel: Hydrates dry wounds; used for necrotic wounds or burns.

• Foam Dressing: Highly absorbent; provides cushioning for heavy exudate.

• Alginate Dressing (e.g., AlgiDERM, Kaltostat): Manufactured from seaweed; very absorbent for bleeding or heavily exudative/infected wounds.

• Antimicrobial Dressing: Contains silver or iodine to reduce bacterial load.

• General Principles for Dressing Changes:

  • Use aseptic (clean) technique.

  • Assess for signs of infection: Increased redness, swelling, warmth, pain, foul odor, or fever.

  • Document: Type, size, drainage amount, wound appearance, and patient response.

Allergy Patch Testing

• Purpose: A diagnostic procedure for identifying substances causing allergic contact dermatitis (delayed hypersensitivity reaction appearing $24$ to $72$ hours after exposure).

• Tested Substances: Adhesives, fragrances, metals (nickel/gold), preservatives, plastics, rubber, and topical medications.

• The $5$-Day Procedure Cycle:

  • Day $1$ (Application): Small amounts of allergens are applied to the upper back in adhesive patches. Each is numbered and the skin is marked.

  • Day $3$ (First Reading): Patches are removed. The provider examines the skin for erythema (redness), edema (swelling), papules (bumps), or vesicles (blisters). Skin is re-marked.

  • Day $5$ (Final Reading): The provider assesses for delayed reactions. Results are recorded as negative, doubtful, positive (red/raised), or strong positive (blisters).

• Patient Instructions: Keep the area dry (no bathing/swimming/sweating), do not scratch, leave markings intact, and wear loose clothing to reduce friction.