ByDr Chiba Hiroshi*

Let's say you are suffering from long-lasting body pain. You've tried drugs from the pharmacy or tried yoga classes, but nothing seems to help. What should you do in this situation?

To get better control, you need to know the basic principles of pain.

When a part of the body is damaged due to injury or illness, the sensory nerves around the injured tissue instantaneously send electrical signals to the brain, signaling the body's injury as pain. Pain is essential information for quickly detecting abnormalities in the body and protecting yourself from further danger. The pain at this time is called nociceptive pain.

Paracetamol and NSAIDs (which stands for Non-Steroidal Anti-Inflammatory Drugs like aspirin, ibuprofen, etc.) are prescribed against nociceptive pain. You can even buy them as over-the-counter medicine at pharmacies. Damaged cells release small particles called prostaglandins, which can intensify pain or generate fever. These drugs exert their analgesic effect by blocking prostaglandins. Topical as well as oral medications may be useful.

However, suppose the pain persists even after taking paracetamol or NSAIDs for a certain period. In that case, it is necessary to consider other possibilities as the cause of the pain.

At first, we need to consider whether the pain is caused by treatable diseases.

Diseases such as migraine and polymyalgia rheumatica have particular medications that can control the pain through treatment if accurately diagnosed. Doctors should be on the lookout for these diseases. Malignant cancers can also cause long-lasting pain, so a thorough investigation is necessary.

Pain that lasts for more than three months without such a manageable disease is called chronic pain. Paracetamol is known to be ineffective in treating osteoarthritis and chronic back pain.

Next, consider the possibility of neuropathic pain. Neuropathic pain is a condition in which the sensory nerves get damaged. They transmit electrical signals to the brain that causes pain. Even if there is no damage to the body, the brain receives the electrical signals and feels the pain. NSAIDs and acetaminophen are ineffective for neuropathic pain.

Furthermore, when there is long-lasting pain, sensitisation for pain may occur.

Sensitisation for pain means that the brain or nerve functions have been altered by prolonged pain so that even the slightest stimulus is perceived as pain. There is no test to detect sensitisation. Doctors have to diagnose it solely based on the patient's complaints, clinical course, and some basic examinations. Therefore, it is difficult to diagnose the pain caused by sensitisation. Even if it can be diagnosed accurately, it takes a long time to treat because of the brain and nerves' structural changes. Therefore, multidisciplinary treatments using various medications, cognitive therapy, mindfulness, or other practical means like yoga, are necessary in many cases.

Medications to ease neuropathic pain or sensitisation are antidepressants or anticonvulsants, which act on the malfunctioning brain or nerves. It does not necessarily mean that you have epilepsy or depression.

In general, opioids such as oxycontin and fentanyl would not be prescribed for chronic pain. Although opioids effectively treat pain caused by malignant cancers, they are withheld from non-cancer chronic pain for concerns about dependence unless there is no other option.

Lastly, let's look at the side effects of these medications.

Acetaminophen is an extremely safe drug and has few side effects as long as it is taken in the proper dosage. However, taking too much of it can damage the liver.

It is well known that NSAIDs can cause gastric mucosal damage. In particular, aspirin can inhibit hemostasis, so for example, avoid taking it if you have dengue fever. When you get seasonal flu with fever, taking NSAIDs can cause Rye syndrome, a severe complication.

Antidepressants and anticonvulsants have the side effect of making you drowsy since they affect the central nervous system.

Opioids have various side effects such as drowsiness, constipation, and the formation of physical and psychological dependence, which is a risk of making pain control more difficult.

Thus, to keep pain under control and get your life back, it is crucial to take the proper medication to treat and alleviate the cause of pain.  Family Medical Practice

*Dr Chiba Hiroshi is a Japanese Family Doctor with 20 years of experience working in Japan and Cambodia, specializing in primary care, travel medicine, and urgent care. He graduated from Tohoku University school of medicine in 1998 and received his PhD in Geriatrics in 2004. He provides consultation on a wide range of health problems for all age groups. Other areas of specialties and interests include infectious disease, infection control, and medical education.

Family Medical Practice was the first foreign-owned primary healthcare provider in Viet Nam, and has consistently remained at the forefront of international-standard medicine since 1995. It offers extensive healthcare and emergency medical services nationwide to Vietnamese, expatriate and corporate customers.

 For more advice on any medical topics, visit Family Medical Practice Hanoi at: 298 I Kim Mã, Ba Đình District. Tel: (024) 3843 0748.  E: hanoi@vietnammedicalpractice.com.

FMP’s downtown Hồ Chí Minh City location is: Diamond Plaza, 34 Le Duẩn, District 1; 95 Thảo Điền, District 2. Tel: (028) 38227848. E: hcmc@vietnammedicalpractice.com

FMP Đa Nẵng is located at 96-98 Nguyễn Văn Linh, Hải Chau District, Đa Nẵng. Tel: (0236) 3582 699. E: danang@vietnammedicalpractice.com.