Abstract: Provided are kits containing a base composition and an active pharmaceutical ingredient for transdermal delivery of active pharmaceutical ingredients. Examples of active pharmaceutical ingredients include amitriptyline, baclofen, cyclobenzaprine HCl, ibuprofen, lidocaine HCl, naproxen and tramadol, ketoprofen, diclofenac, phenylbutazone, mefenamic acid, flubiprofen, piroxicam, guaifenasin, prilocaine, bupivicaine, tetracaine, nifedipine, verapamil, orphenadrine, imipramine, ketamine, gabapentin, carbamazepine, menthol, capsaicin, clonidine, dexamethasone, dextromethorphan, testosterone, progesterone, and estrogens.