Buprenorphine patches
Introduction
Buprenorphine is a synthetic analgesic, belonging to the opioid group of drugs. It is basically an opioid drug, having a combination of agonist and antagonist properties and is 25 times more potent than morphine.
Analgesics are basically the drugs that relieve pain by acting in the central nervous system or peripheral pain mechanisms, without altering consciousness. They are typically marked by a slower onset of action and longer duration.
After a single dose, pain is relieved for 6-8 hrs. However with repeated use, duration of action increases to 24 hours.
Working Principle
Buprenorphine is known to produce the action of natural endorphins by stimulating the opioid receptors in the brain and spinal cord. These block the transmission of pain signals sent by the nerves to the brain. Hence, even if the cause of the pain still exists, less pain is actually felt.
In other words, the Buprenorphine patch produces the desired effect by acting on the mew (u) receptors present in the brain, spinal cord and peripheral tissue to bring about analgesia.
There are basically two kinds of mew (u) receptors:
Mew1 (u1)- It has a high affinity for morphine. This receptor mediates supraspinal analgesic effect of morphine. Mew2 (u2)- It has a low affinity for morphine. It mediates the other side effects of morphine like constipation, respiratory depression, etc.
Research indicates that the 7-day patch has shown effective results in treating chronic osteoarthritic pain, low back pain and non-malignant pain.
Key Aspects
Buprenorphine patches are most commonly being used for long lasting painful conditions requiring an opioid analgesic, such as in the case of cancer pain.
They are also used for temporary relief from minor aches and pains of muscles and joints associated with arthritis, simple backache, strains and sprains.
Such patches are a method and composition for enhancing absorption of topically administered physiologically active agents. The absorption is through the skin and mucous membrane of humans in a transferal device or formulation for local use.
It comprises a therapeutically effective amount of a pharmaceutically active agent and a non-toxic effective amount of penetration enhancing agent. The drug is mainly absorbed through the skin through various pores present in the epidermal (outermost) layer of the skin.
Directions for use
Health care providers and pharmacists lay down the following specific conditions for the proper use of buprenorphine patches. Here we list the most important amongst them.
The patch should be applied to non-irritated, intact skin of the upper outer arm, upper chest, upper back or the side of the chest, leaving out any area that has large scars. Only use clean water to clean the site of application. The patch should be applied immediately upon removal from the sealed sachet. The patch should be worn continuously for 7 days. While wearing the patch, patients are advised to stay away from external heat sources such as heating pads, electric blankets, heat lamps etc. After removal of a patch, a new patch should not be applied to the same site for at least 3-4 weeks.
Buprenorphine Patches – Key Advantages
The buprenorphine patches offer a vast series of advantages as a medication for pain relief. Here we’ve listed the main benefits of using these patches.
It gives a cool penetrating pain relief effect It can be adhered and removed easily It is neither messy nor greasy It does not emit any embarrassing odour Patches are effective for hours and right at the location of the pain Patches are thin enough to wear unnoticed under clothes, whether at day or night It adheres firmly without the need of additional fixing aids on muscles or joints. Can be removed easily
Side Effects
Though rare, but Buprenorphine patches can lead to a series of side effects, when administered orally or injected. Here we list the main amongst them.
Sedation Vomiting Cardiovascular effects Postural hypotension Respiratory depression Physical as well as psychological dependence develops with chronic use. Low degree of tolerance Abuse liability may also be there.
In addition, the following individuals are advised against the usage of buprenorphine patches:
Children below 12 years of age Individuals with allergies or hypersensitive individuals Individuals with skin infections Individuals who are dependant on other opioids because it can precipitate withdrawal symptoms, including pain
Important Information
It is important to note that physical dependence may develop with chronic use of buprenorphine. If a withdrawal symptom does occur when it is discontinued, it is usually of mild to moderate intensity, occurs within 2 days and resolves within 2 weeks.
However, transdermal buprenorphine may have lower abuse potential than other buprenorphine dosage forms because of the relatively low plasma concentrations achieved, the slow onset of effect and because it is likely to be difficult to extract the drug from the matrix design.
Misuse could take the form of using excessive amounts of the intact patch or applying it to sites that would enhance systemic absorption. It should be used with caution in people with a past history of dependence on alcohol or other drugs.
