CAPSAICIN
| CAPSAICIN (cap-say'i-sin) Axsain, Capsaicin, Capsin, Capsacin-P, Dolorac, Zostrix, Zostrix-HP Classifications: topical analgesic; Therapeutic: topical analgesic |
Availability
0.025%, 0.075% lotion; 0.025%, 0.075%, 0.25% cream; 0.025%, 0.05% gel
Action
Capsaicin is an alkaloid derived from plants and used as a topical analgesic. Capsaicin depletes and prevents reaccumulation of Substance P, the primary chemical mediator of pain impulses from the periphery to the CNS.
Therapeutic Effect
Renders skin and joints insensitive to pain; therefore, it serves as an effective peripheral analgesic.
Uses
Temporary relief of pain from arthritis, neuralgias, diabetic neuropathy, and herpes zoster.
Unlabeled Uses
Phantom limb pain, psoriasis, intractable pruritus.
Contraindications
Hypersensitivity to capsaicin or any ingredient in the cream.
Cautious Use
Patients on ACE inhibitors. Safety and efficacy in children <2 y have not been established.
Route & Dosage
| Analgesia Adult/Child (>2 y): Topical Apply to affected area not more than 3–4 times/d |
Administration
Topical- Apply to affected areas only and avoid contact with eyes or broken or irritated skin.
- If applied with bare hand, wash immediately following application. An applicator or gloved hand may be used to apply cream.
- Avoid tight bandages over areas of application of the cream.
Adverse Effects (≥1%)
CNS: Concentration >1%: neurotoxicity, hyperalgesia. Skin: Burning, stinging, redness, itching. Other: Cough.Interactions
Drug: May increase incidence of cough with ace inhibitors.Pharmacokinetics
Onset: Postherpetic neuralgia: 2–6 wk.Nursing Implications
Assessment & Drug Effects
- Monitor for significant pain relief, which may require 4–6 wk of application three or four times daily.
- Monitor for and report signs of skin breakdown as these generally indicate need for drug discontinuation.
Patient & Family Education
- Report local discomfort at site of application if discomfort is distressing or persists beyond the first 3–4 d of use.
- Use caution in handling contact lenses following application of cream. Wash hands thoroughly before touching lenses.
- Notify physician if symptoms do not improve or condition worsens within 14–28 d.
- Apply frequently three or four times daily to maximize therapeutic effectiveness.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; 
Canadian drug name; 
Prototype drug