Transient increased pain at application site (dissipates w/ continued use)
Application site erythema
Pain
Nausea/vomiting
Rash, dryness pruritus, edema, exfoliation, skin odor
Hypertension
Sinusitis, bronchitis, cough
Dizziness, Headache
Capsaicin
Ethacrynic acid
Ecstasy 
Naphthalene
Toxic alcohols
Strychnine
Monkeypox
N,N-Dimethyltryptamine