Transdermal patch

Not to be confused with dermal patch.
A 21mg dose Nicoderm CQ patch applied to the left arm
Contraceptive patch
Clonidine tablets and transdermal patch

A transdermal patch is a medicated adhesive patch that is placed on the skin to deliver a specific dose of medication through the skin and into the bloodstream. Often, this promotes healing to an injured area of the body. An advantage of a transdermal drug delivery route over other types of medication delivery such as oral, topical, intravenous, intramuscular, etc. is that the patch provides a controlled release of the medication into the patient, usually through either a porous membrane covering a reservoir of medication or through body heat melting thin layers of medication embedded in the adhesive. The main disadvantage to transdermal delivery systems stems from the fact that the skin is a very effective barrier; as a result, only medications whose molecules are small enough to penetrate the skin can be delivered by this method. A wide variety of pharmaceuticals are now available in transdermal patch form.

The first commercially available prescription patch was approved by the U.S. Food and Drug Administration in December 1979. These patches administered scopolamine for motion sickness.[1][2]

Adverse events


The main components to a transdermal patch are:

Other components includes: Stabilizer (anti oxidants), Preservatives etc.


Sample transdermal patches. On left is a 'reservoir' type, on the right a 'Single-layer Drug-in-Adhesive' version. Both contain exactly the same level of the same active ingredient with identical release rates.

There are five main types of transdermal patches.

Single-layer Drug-in-Adhesive

The adhesive layer of this system also contains the drug. In this type of patch the adhesive layer not only serves to adhere the various layers together, along with the entire system to the skin, but is also responsible for the releasing of the drug. The adhesive layer is surrounded by a temporary liner and a backing.

Multi-layer Drug-in-Adhesive

The multi-layer drug-in-adhesive patch is similar to the single-layer system; the multi-layer system is different, however, in that it adds another layer of drug-in-adhesive, usually separated by a membrane (but not in all cases). One of the layers is for immediate release of the drug and other layer is for control release of drug from the reservoir. This patch also has a temporary liner-layer and a permanent backing. The drug release from this depends on membrane permeability and diffusion of drug molecules.


Unlike the single-layer and multi-layer drug-in-adhesive systems, the reservoir transdermal system has a separate drug layer. The drug layer is a liquid compartment containing a drug solution or suspension separated by the adhesive layer. The drug reservoir is totally encapsulated in a shallow compartment molded from a drug-impermeable metallic plastic laminate, with a rate-controlling membrane made of a polymer like vinyl acetate on one surface. This patch is also backed by the backing layer. In this type of system the rate of release is zero order.


The matrix system has a drug layer of a semisolid matrix containing a drug solution or suspension. The adhesive layer in this patch surrounds the drug layer, partially overlaying it. Also known as a monolithic device.

Vapour Patch

In a vapour patch, the adhesive layer not only serves to adhere the various layers together but also to release vapour. Vapour patches release essential oils for up to 6 hours and are mainly used for decongestion. Other vapour patches on the market improve quality of sleep or aid in smoking cessation.

Regulatory aspects

A transdermal patch is classified by the U.S. Food and Drug Administration as a combination product, consisting of a medical device combined with a drug or biological product that the device is designed to deliver. Prior to sale in the United States, any transdermal patch product must apply for and receive approval from the Food and Drug Administration, demonstrating safety and efficacy for its intended use.[16]


  1. Segal, Marian. "Patches, Pumps and Timed Release: New Ways to Deliver Drugs". Food and Drug Administration. Archived from the original on 2007-02-10. Retrieved 2007-02-24.
  2. "FDA approves scopolamine patch to prevent peri-operative nausea". Food and Drug Administration. 1997-11-10. Archived from the original on 2006-12-19. Retrieved 2007-02-12.
  3. Nachum Z, Shupak A, Gordon CR (2006). "Transdermal scopolamine for prevention of motion sickness : clinical pharmacokinetics and therapeutic applications". Clinical Pharmacokinetics. 45 (6): 543–66. doi:10.2165/00003088-200645060-00001. PMID 16719539.
  4. Berner B, John VA (February 1994). "Pharmacokinetic characterisation of transdermal delivery systems". Clinical pharmacokinetics. 26 (2): 121–34. doi:10.2165/00003088-199426020-00005. PMID 8162656.
  5. First Databank Inc. "Clonidine - Transdermal (Catapres-TTS) side effects, medical uses, and drug interactions". Retrieved 2010-09-28.
  6. Peck, Peggy (2006-03-01). "FDA Approves First Antidepressant Transdermal Patch". Retrieved 2010-09-28.
  7. Cabray, Matthew (2006-04-12). "Transdermal Patch Approved For Treatment Of ADHD". Retrieved 2010-09-28.
  8. "'Revolutionary' 24-hour slow release 5-HTP transdermal patch, launched in early 2014 in the United Kingdom". Retrieved 2014-06-18.
    • PatchBrothers, lifestyle, party patches, body boosts and transdermal pick me ups
    Peck, Peggy (2007-07-10). "Medical News: FDA Approves Rivastigmine Patch for Alzheimer's Disease". Retrieved 2011-03-10.
  9. "FDA ALERT (07/2005): Narcotic Overdose and Death". Food and Drug Administration. 2005-07-15. Archived from the original on 2007-02-20. Retrieved 2007-02-24.
  10. Megget, Katrina (2007-09-05). "ADHD Transdermal Patches Withdrawn". Retrieved 2010-09-28.
  11. Silverman, Ed (2008-02-12). "J&J and Sandoz Recall Fentanyl Patches". Retrieved 2010-09-28.
  12. As stated on the packaging and labels of Sandoz-branded Fentanyl Transdermal System products, revised March 2009.
  13. "FDA Public Health Advisory: Risk of Burns during MRI Scans from Transdermal Drug Patches with Metallic Backings". Archived from the original on March 7, 2009. Retrieved March 9, 2009.
  14. Brown, MR: "Analgesic patches and defibrillators: a cautionary tale", Europace,2009 Nov;11(11):1552-3
  15. "Combination Products; FAQ". Retrieved April 10, 2012.

Further reading

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