What is topical capsaicin?
Capsaicin is available as a topical cream that has been found to help relieve pain from some arthritic conditions such as osteoarthritis, rheumatoid arthritis. It has also been used to treat cutaneous dysaesthesia and neuralgia.
Capsaicin is available as a 0.025% or 0.075% strength cream in a 45-g tube. The trade name is Zostrix® or Zostrix-HP®.
How does topical capsaicin work?
Capsaicin is the purified extracted alkaloid from red chilli peppers (capsicums). This is the substance that makes chilli peppers hot. The purified form capsaicin has been found to relieve pain by reducing substance P, which is found at nerve endings and is involved in transmitting neuralgic and arthritic pain signals to the brain. Pain relief is not instantaneous after application as it is the cumulative depletion of substance P over a period of weeks that brings the full effect.
What is capsaicin used for?
Capsaicin is approved for use for the symptomatic relief of pain associated with osteoarthritis.
It has been used to treat neuralgic pain including:
- Post-herpetic neuralgia: mild to severe pain on the surface of the skin in patients who have just had shingles (herpes zoster). This pain occurs in about 20% of people and can persist for a month or longer after the shingles rash heals.
- Trigeminal neuralgia: a disorder of the trigeminal nerve that causes episodes of intense, stabbing, electric shock-like pain in the areas of the face where the nerve endings reach (lips, eyes, nose, scalp, forehead, upper jaw, and lower jaw).
- Atypical facial pain: facial pain, often described as burning, aching or cramping that occurs on one side of the face, and can extend into the upper neck or back of the scalp.
- Brachioradial pruritus: an itchy condition of the arms localized to the skin near the elbows.
- Nodular prurigo: a chronic condition characterised by intensely itchy lumps.
How to use capsaicin cream
Capsaicin cream can be purchased over-the-counter from pharmacies. Capsaicin should be used as follows.
- Apply a small amount of cream with fingers and rub it well into the affected area 3 or 4 times daily.
- Wash hands after application if hands are not the treatment sites or if applying the cream to someone else. If using for arthritis affecting the hands, do not wash the hands for at least 30 minutes after applying the cream.
- If using for treatment of post-herpetic neuralgia, only apply capsaicin after the shingles sores have healed.
- Capsaicin must be used regularly every day as directed. Immediate pain relief is not to be expected, depending on the type of pain. The full effect may take several weeks of regular use to achieve.
- Continue to use capsaicin regularly if required.
Capsaicin cream should not be applied to broken or infected skin. Seek medical advice first.
Avoid use near eyes or other sensitive areas of the body. If capsaicin gets into the eyes, flush them with water. Wash other sensitive areas with warm soapy water.
Tight bandages should not be applied on top of capsaicin cream.
The most common side effect of capsaicin use is a feeling of warmth and stinging or a sensation of burning after application. This sensation is related to the action of capsaicin on the skin and is to be expected. Approximately 50% of patients will experience some mild to moderate stinging or burning. This sensation usually diminishes after the first few days of application and in most cases will disappear with time and continued use.
Methods used to reduce this sensation include:
- Avoid taking a hot bath or shower just before or after applying capsaicin cream.
- Try to keep cool, do not wear tight clothing or become too warm as heat may increase the sensation.
- Maintain recommended or prescribed dosing schedule.
We suggest you refer to your national drug approval agency such as the Australian Therapeutic Goods Administration (TGA), US Food and Drug Administration (FDA), UK Medicines and Healthcare products regulatory agency (MHRA) / emc, and NZ Medsafe, or a national or state-approved formulary eg, the New Zealand Formulary (NZF) and New Zealand Formulary for Children (NZFC) and the British National Formulary (BNF) and British National Formulary for Children (BNFC).