Several categories of drugs can cause harm through skin contact alone, ranging from chemotherapy agents that damage DNA to hormone gels that transfer active medication to anyone who touches the treated skin. The risks vary widely: some drugs cause local irritation, others absorb through the skin and produce full-body effects, and a few pose serious reproductive dangers. Here’s what you need to know about each one.
Chemotherapy and Cytotoxic Drugs
Cancer-killing drugs are the most well-known category of medications you should never touch with bare hands. These drugs work by damaging or destroying rapidly dividing cells, and they don’t distinguish between cancer cells and the healthy cells of a person who accidentally handles them. Healthcare workers who prepare or administer these agents without proper protection have higher rates of skin rashes, reproductive problems (including infertility, miscarriages, and birth defects), and possibly leukemia and other cancers over time.
The National Institute for Occupational Safety and Health (NIOSH) maintains a formal list of hazardous drugs that require special handling in healthcare settings. As of 2024, the list continues to grow, with new cancer drugs added as recently as mid-2025. Specific agents worth knowing about include:
- Cyclophosphamide, chlorambucil, and busulfan: alkylating agents that can cause skin rashes, hyperpigmentation, and nail changes even in patients receiving them therapeutically. Direct skin contact during handling exposes you to the same risks.
- 5-fluorouracil (5-FU) and capecitabine: antimetabolites known for causing “hand-foot syndrome” in patients, with redness, swelling, blistering, and peeling on palms and soles. Handling these without gloves puts you in direct contact with the same irritant.
- Vinca alkaloids and taxanes: spindle inhibitors used for many solid and blood cancers. If these drugs leak from an IV into surrounding tissue, they cause direct soft-tissue damage and ulceration. Skin contact during preparation carries a similar risk.
- Platinum-based agents: these can trigger severe allergic reactions, including immune-mediated skin responses.
Newer targeted therapies aren’t necessarily safer to handle. EGFR inhibitors used for lung and colorectal cancers cause widespread skin dryness in over 90% of patients who take them, along with a follicular rash that can become painful and infected. The drug itself is potent enough that handling precautions apply.
Testosterone and Hormone Gels
Topical testosterone is one of the most commonly prescribed drugs that poses a real contact risk in everyday life, not just in hospitals. After a man applies testosterone gel to his shoulders or upper arms, the medication sits on the skin surface and can transfer to anyone who touches that area. Women and children are especially vulnerable.
The FDA requires a boxed warning on testosterone gel products for exactly this reason. Children who have been accidentally exposed through skin-to-skin contact with a treated adult have developed enlarged genitals, early pubic hair growth, increased sexual behavior, and aggressive behavior. Women exposed this way may develop acne and unexpected hair growth.
If you use testosterone gel, let it dry completely before putting on clothes that cover the area. Wash your hands thoroughly after application. If someone does touch the treated skin before it’s been washed, they should scrub that area with soap and water immediately.
Nitroglycerin
Nitroglycerin, commonly used for chest pain and heart conditions, passes through intact skin rapidly. That’s the whole point of nitroglycerin patches and ointments, but it also means accidental contact can produce real symptoms. Touching a nitroglycerin patch or the ointment with bare hands can cause headaches, dizziness, lightheadedness, and a drop in blood pressure. At higher exposure levels, it can interfere with your blood’s ability to carry oxygen, causing fatigue, confusion, a bluish tint to the skin and lips, and in extreme cases, collapse.
Paramedics and nurses are trained to check patients for nitroglycerin patches before performing CPR or using a defibrillator, partly because the patch can transfer medication to the rescuer’s hands. If you’re a caregiver helping someone apply or remove a nitroglycerin patch, wear gloves every time.
Finasteride and Dutasteride
These medications treat enlarged prostate and male-pattern hair loss by blocking the conversion of testosterone into a more potent form. That mechanism is exactly what makes them dangerous during pregnancy. If a pregnant woman handles a crushed or broken tablet, the drug can theoretically absorb through her skin and interfere with the development of male genitalia in a fetus.
The practical risk from briefly touching a broken tablet is low. Intact tablets have a coating that prevents absorption. But as a precaution, pregnant women should avoid handling crushed or broken finasteride or dutasteride tablets entirely. If contact does happen, washing your hands with soap and water is sufficient.
Why DMSO Makes Some Drugs More Dangerous
Dimethyl sulfoxide (DMSO) is an industrial solvent that penetrates skin so quickly that spilling it on your hand produces a garlic taste in your mouth within seconds. On its own, DMSO is used in some medical and veterinary settings. The real danger is that DMSO acts as a carrier, pulling other chemicals through the skin along with it.
DMSO disrupts the outermost layer of skin, rearranging the fats that normally act as a barrier. It also creates tiny solvent pockets in deeper tissue that draw dissolved substances inward and into local blood vessels. This property has been deliberately used to enhance the penetration of cancer drugs like 5-fluorouracil for treating skin malignancies. But it also means that if a hazardous substance is dissolved in or mixed with DMSO, your skin offers almost no protection against it. Any unknown liquid that could contain DMSO should be treated with extreme caution.
What About Fentanyl?
This is one of the most common concerns people have, and the reality is more nuanced than headlines suggest. Fentanyl does absorb through mucous membranes (the inside of your mouth, nose, or eyes) at a rate more than 30 times higher than through intact skin. Medical fentanyl patches work by using special formulations and adhesives designed to push the drug through skin slowly over 48 to 72 hours.
Briefly touching powdered fentanyl with dry, intact skin is not the same as wearing a patch. The American College of Medical Toxicology and the American Academy of Clinical Toxicology have stated that incidental skin contact with fentanyl is not expected to cause overdose in emergency responders. The real danger comes from inhaling airborne powder or touching your mouth, nose, or eyes after contact. That said, gloves are still a smart precaution because they eliminate any absorption pathway and prevent you from unknowingly transferring powder to your face.
How to Handle These Drugs Safely
The single most important step is wearing gloves. For most situations involving pills, patches, or topical medications, standard disposable gloves (nitrile is preferred over latex) provide adequate protection. If you’re a home caregiver handling chemotherapy drugs, you should also have a spill kit nearby and written instructions from the prescribing team on how to dispose of leftover medication and contaminated materials.
If you do get a hazardous drug on your skin, flush the area immediately with soap and water. If the chemical has soaked through your clothing, remove the clothing first, then wash the skin. For eye exposure, rinse with clean water for at least 15 minutes. Irritation that persists after washing warrants medical attention.
For everyday household situations, the drugs most likely to cause problems are topical hormones (testosterone gel), nitroglycerin products, and oral chemotherapy pills that a family member may be taking at home. Treat any of these with the same simple rule: don’t touch them without gloves, and wash immediately if you do.