What is a transdermal patch, and how does transdermal delivery work?
A transdermal patch is a device that delivers active ingredients through the skin —the skin absorbs the active ingredient, which enters the bloodstream directly, bypassing first-pass metabolism in the liver. This feature distinguishes it from oral formulations. Our line of pain relievers includes various types of patches depending on the indication.
- Mechanism of delivery: the active ingredient contained in the patch’s reservoir diffuses through the control membrane → passes through the epidermis → reaches the vascularized dermis → is released directly into the bloodstream—resulting in a stable blood concentration without peaks or troughs
- Advantage of avoiding first-pass metabolism: drugs that undergo extensivehepatic metabolism (estrogens, testosterone, certain opioids) are more effective as patches—plasma concentrations are more stable than with oral administration
- Duration of action: 24 hours to 7 days depending on the formulation and active ingredient—regular replacement maintains constant therapeutic concentrations
- Required galenic conditions: sufficient lipophilicity of the active ingredient (crosses the skin’s lipid barrier), low effective dose, molecular weight < 500 Da
What types of transdermal patches are there, and for what indications?
Transdermal patches cover a wide therapeutic range—each class has its own specific uses.
- Pain relief patches: lidocaine (local anesthetic—neuropathic pain), fentanyl (opioid—severe chronic pain), high-dose capsaicin (C-fibers—neuropathies)—a doctor’s prescription is required for concentrated formulations
- Anti-inflammatory patches: transdermal NSAIDs (diclofenac, ketoprofen)—superficial joint and muscle pain—fewer gastrointestinal side effects than oral NSAIDs
- Heating patches: iron oxidation reaction — local thermotherapy at 40–45°C for 8–12 hours — low back pain, neck tension, menstrual pain
- Smoking cessation patches (nicotine): 3 concentration levels — nicotine replacement therapy — dosage gradually decreases over 8–12 weeks
- Hormone patches: estrogens (menopause treatment), testosterone (hypogonadism) — more stable plasma concentration than with oral medication — requires a doctor’s prescription
How do you apply a transdermal patch, and which areas are best?
The application technique directly affects the patch’s effectiveness and skin tolerance.
- Application site: clean, dry skin, free of hair and irritation — chest, back, shoulder, arm (depending on the type) — avoid skin folds, areas prone to friction, and areas that have undergone radiation therapy
- Rotate application sites: change the area with each new patch — prevents maceration and skin reactions caused by accumulation
- Technique: Press firmly for 30 seconds after application—do not cut or fold the patch—wash your hands after handling (active ingredient may transfer)
- Showering and bathing: Most patches are water-resistant — check the manufacturer’s instructions — press down on the edges after exposure to water to ensure adhesion
- Sensitive, eczema-prone, or psoriatic skin: consult a healthcare professional before use—the patch may aggravate preexisting lesions
Storage, side effects, and when to seek medical advice?
- Storage: Keep in original packaging until use—store at temperatures below 25°C—do not freeze, keep away from heat sources (such as a car in summer), and avoid direct sunlight
- Disposal: Fold the used patch in half (adhesive side against itself)—do not flush down the drain or burn—return medicated patches (fentanyl, hormones) to a pharmacy
- Common skin side effects: erythema at the application site (common, mild) — itching — allergic contact reaction (to the adhesive or active ingredient) — if blisters, swelling, or generalized eczema occur: stop use immediately and consult a healthcare provider
- General contraindications: broken, burned, or infected skin at the application site — skin affected by active atopic dermatitis
- Patches containing potent active ingredients (fentanyl, hormones): require a prescription — never increase the dose on your own — risk of transdermal overdose if applied to heated skin (hot bath, fever)
