Using our advice

Transdermal patches can present common challenges that affect drug delivery, dosing accuracy, and patient outcomes. This article offers practical guidance for identifying and managing these issues in clinical practice.

Adhesion problems 

Adhesion issues with transdermal patches can be common, particularly in hot weather. Patches that do not stay in full contact with the skin may not deliver the medication effectively or the patch may fall off.

If you experience adhesion issues, refer to the section on applying transdermal patches in our article Using transdermal patches safely in healthcare settings. We provide tips on selecting an appropriate application site.

If a patch has partially fallen off, it can be reapplied if it still adheres well. Do not deliberately remove a patch before reapplying as this will reduce its ability to adhere.

If a patch does not stick properly, options include: 

• using tape, such as Micropore, around the edges 
• using a non-occlusive transparent dressing, such as Tegaderm, over the patch 
• applying a new patch

Do not use occlusive dressings to attach patches as it may increase the rate of drug absorption from the patch.

Do not conceal the patch completely with an opaque dressing or tape. Others must be able to see the patch, even if the patient self-manages, to ensure safe identification in emergencies.

Skin reactions

Transdermal patches can cause adverse skin reactions. The most common skin reactions are irritant contact dermatitis, although allergic contact dermatitis may also occur.

Allergic contact dermatitis is usually triggered by the adhesive but can also be caused by the active drug or other excipients.

Reducing risk of skin reactions

To reduce the risk of skin reactions: 

• follow the manufacturer’s instructions 
• rotate application sites and allow previous application sites to rest
• apply moisturisers or emollients after patch removal as part of skincare, but avoid using them immediately before patch application
• use recommended techniques for patch application and removal – see our advice in our article Using transdermal patches safely in healthcare settings

Evaluating skin reactions 

When assessing a skin reaction:

• if the reaction is confined to the patch area and resolves after the patch is removed, it is more likely to be irritant contact dermatitis
• if the reaction extends beyond the patch and the reaction continues or worsens after the patch is removed, it is more likely to be allergic contact dermatitis
• check for known allergies or sensitivities to medicines, excipients, cosmetics, or chemicals

If you are unsure whether a reaction is allergic or irritant contact dermatitis, consider referring for further dermatological assessment.

Managing persistent skin reactions

Switch to a different brand if skin reactions persist despite correct application, removal and skincare, as the adhesive may be the cause. 

If the patient’s reaction is believed to be due to the adhesive, check the type of adhesive. If the patient has reacted to an acrylate adhesive, choose a patch with a non-acrylate adhesive. 

If switching to a different brand, patch or a non-patch formulation is not possible, or for further advice on managing the switch, consult a specialist or your medicines information service. Primary care healthcare professionals can contact the SPS Medicines Advice service. 

Missing, omitted or delayed application

Treatment interruption

If patch application is interrupted, either due to omission, extended use, or delayed application, determine the duration and consult the prescriber promptly. Re-titration or rescue medication may be needed if treatment interruption risks loss of clinical effectiveness. This is especially important for patches used in pain management, as it may take days to regain therapeutic levels.

Even after patch removal, residual drug in the skin can maintain significant blood levels for up to 24 hours. For guidance on restarting treatment or issuing a new prescription, refer to the product information and seek clinical advice as needed.

Follow these steps if a patch has completely fallen off or application is omitted or delayed: 

Loss of clinical effect

Some patients may experience diminished therapeutic effect before the next scheduled patch change, even if they do not require, or cannot tolerate a higher dose. This is sometimes referred to as end-of-dose-phenomenon.

After ruling out poor adhesion, reducing the dosing interval may help maintain consistent clinical benefit although this approach is considered off-label. For example, fentanyl patches are occasionally changed every 48 hours instead of the standard 72 hours.

Switching between patches and other formulations

After a transdermal patch is applied, medication levels in the bloodstream rise gradually and decline slowly following removal. The rate of absorption and elimination varies depending on the active ingredient and patch design. For further details, refer to the product information or contact the manufacturer.

When switching between transdermal patches, or to and from other formulations, timing is critical. A gap that’s too short may increase the risk of toxicity or drug interactions. A gap that’s too long may result in poor symptom control.

The appropriate switching strategy depends on several factors, including the specific products involved, the clinical indication, symptom control, the availability of breakthrough medication for analgesia and the potential for adverse effects or toxicity. Check the product information and seek specialist advice if needed.

Accidental exposure

If a patch has accidentally transferred to another person, either through an administration error or transfer issues, remove it immediately and seek urgent medical assistance.

Healthcare professionals with access to Toxbase (subscription required) can seek further guidance on the clinical risk of exposure.

Report accidental exposure or any adverse events to the MHRA Yellow Card reporting system. If unsure, seek advice from the prescriber or pharmacist. 

Risk of use in MRI scans

Some transdermal patches contain metal which could cause burns or drug toxicity if worn during an MRI scan.

Identifying patches that contain metal can be difficult, so remove all patches as a precaution or follow local policy.

Post MRI scan: 

• apply a new patch
• maintain the patient’s usual patch change schedule, even if the newly applied patch is changed earlier than usual.