What Is Pain?
Pain is so universal that it barely needs a definition to be understood.
What follows is a discussion of physical pain, not emotional pain.
The International Association for the Study of Pain (IASP) defines pain as: An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.
According to the IASP, pain is the most frequent reason for emergency department (ED) visits, accounting for over 70% of visits. In the US, more than 115 million ED visits occur each year with acute headache alone accounting for 2.1 million of these visits. Acute pain is also a common reason for visits to family practice, sports medicine, and internal medicine health care practitioners.
Recent Center for Disease Control and Prevention (CDC) and National Center for Health Statistics (NCHS) data suggest substantial rates of pain from various causes and that most people in chronic pain experience pain in multiple areas of the body. For U.S. adults reporting pain, causes include: severe headache or migraine (16.1%), low back pain (28.1%), neck pain (15.1%), knee pain (19.5%), shoulder pain (9.0%), finger pain (7.6%), and hip pain (7.1%).
The American Academy of Pain Medicine (AAPM), in its report with the Institute of Medicine of the National Academies, Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education and Research, estimates that at least 100 million adults in the US have common chronic pain conditions.
Pain helps us to remove ourselves from damaging situations, protect an injury while it heals and learn to avoid similar situations in the future. Generally, pain resolves when the painful stimulus is removed and the body has healed, but sometimes pain may persist. Pain may also arise in the absence of painful stimuli, damage or disease.
Types of Pain:
It’s safe to say most of us are not big fans of pain. Nevertheless, it is one of the body’s most important communication tools. Imagine what would happen if you felt nothing when you put your hand on a hot stove. Pain is one way the body tells you something’s wrong and needs attention.
But pain — whether it comes from a bee sting, a broken bone, or a long-term illness — is also an unpleasant sensory and emotional experience. It has multiple causes, and people respond to it in multiple and individual ways. The pain that you push your way through might be incapacitating to someone else.
Even though the experience of pain varies from one person to the next, it is possible to categorize the different types of pain. Here’s an overview of the different types of pain and what distinguishes them from one another.
There are several ways to categorize pain. One is to separate it into acute pain and chronic pain
Acute Pain: Typically results from injury, disease or inflammation of the tissues. Acute pain is usually confined to a given amount of time and severity and can be diagnosed and treated. Acute pain comes on suddenly and is accompanied by anxiety and emotional distress. Acute pain typically comes on suddenly and has a limited duration. It’s frequently caused by damage to tissue such as bone, muscle, or organs, and the onset is often accompanied by anxiety or emotional distress.
Rarely, it can become chronic pain.
Break-Through Pain (also known as Flare-Up Pain) is transient and excruciating pain beyond the normal pain baseline. Breakthrough pain goes above and beyond the medication taken to prevent and treat persistent pain. It may be caused by changes in treatment or in the underlying disease or physical actions – sneezing or standing up. Breakthrough pain may be caused by stress, worry or anxiety.
About 70% of people with chronic pain treated with pain medication experience episodes of what’s called breakthrough pain. Breakthrough pain refers to flares of pain that occur even when pain medication is being used regularly. Sometimes it can be spontaneous or set off by a seemingly insignificant event such as rolling over in bed. And sometimes it may be the result of pain medication wearing off before it’s time for the next dose.
Chronic Pain: pain that persists over a longer period of time and is resistant to most medical treatments. Chronic pain is widely believed to represent disease itself. It can and often does cause problems for people who live with it. Chronic Pain lasts longer than acute pain and is generally somewhat resistant to medical treatment. It’s usually associated with a long-term illness, such as osteoarthritis. In some cases, such as with fibromyalgia, it’s one of the defining characteristic of the disease. Chronic pain can be the result of damaged tissue, but very often is attributed to nerve damage.
Both acute and chronic pain can be debilitating, and both can affect and be affected by a person’s state of mind. But the nature of chronic pain — the fact that it’s ongoing and in some cases seems almost constant — makes the person who has it more susceptible to psychological consequences such as depression and anxiety.
At the same time, psychological distress can amplify the pain.
Why Do People Experience Pain Differently?
Pain is real and it’s physical — there’s no mistaking that. But pain is measured and specific to one person based on that person’s perception of the pain, and that’s why everyone’s pain is different.
What the brain perceives is indisputably modifiable by emotions. That means that people who are fearful of pain, depressed, or anxious may experience pain differently, and perhaps more severely, than someone who has pain but isn’t experiencing those other emotions.
Classification for Chronic Pain:
Pain is most often classified by the kind of damage that causes it. The two main categories are pain caused by tissue damage, also called nociceptive pain, and pain caused by nerve damage, also called neuropathic pain. A third category is psychogenic pain, which is pain that is affected by psychological factors. Psychogenic pain most often has a physical origin either in tissue damage or nerve damage, but the pain caused by that damage is increased or prolonged by such factors as fear, depression, stress, or anxiety. In some cases, pain originates from a psychological condition.
Pain is also classified by the type of tissue that’s involved or by the part of the body that’s affected. For example, pain may be referred to as muscular pain or joint pain.
Chronic pain is classified by the functional changes associated with the disease or injury.
Neuropathic pain is caused by damage to the brain, spinal cord or peripheral nerves. It is typically described as burning, tingling, shooting, stabbing, stinging or “pins and needles.”
Phantom Pain – pain from a part of the body that has been lost, or from an area from which the brain no longer receives signals. This type of pain is common in amputees.
Psychogenic Pain – (also called psychalgia or somatoform pain) is pain that is caused by, increased, or prolonged by emotional, mental or behavioral patterns.
Nociceptive Pain – pain due to an ongoing tissue injury. Nociceptive pain is often divided into two categories:
- Somatic Pain – pain caused by activation of the pain receptors in the musculoskeletal tissues or the body’s surface. It may be described as dull or aching.
- Visceral Pain – pain caused by damaged or injured internal organs. Usually described as vague, unlocalized pain that may feel like pressure, deep squeezing, dull and diffuse.
Chronic Pain Caused by Tissue Damage (Nocioceptive Pain)
Most pain comes from tissue damage. The pain stems from an injury to the body’s tissues. The injury can be to bone, soft tissue, or organs. The injury to body tissue can come from a disease such as cancer. Or it can come from physical injury such as a cut or a broken bone.
The pain you experience may be an ache, a sharp stabbing, or a throbbing. It could come and go, or it could be constant. You may feel the pain worsen when you move or laugh. Sometimes, breathing deeply can intensify it.
Pain from tissue damage can be acute. For example, sports injuries like a sprained ankle often the result of damage to soft tissue. Or it can be chronic, such as arthritis or chronic headaches. And certain medical treatments, such as radiation for cancer, can also cause tissue damage that results in pain.
Pain Caused by Nerve Damage (Neuropathic Pain)
Nerves function like electric cables transmitting signals, including pain signals, to and from the brain. Damage to nerves can interfere with the way those signals are transmitted and cause pain signals that are abnormal. For instance, you may feel a burning sensation even though no heat is being applied to the area that burns.
Nerves can be damaged by diseases such as diabetes, or they can be damaged by trauma. Certain chemotherapy drugs may cause nerve damage. Nerves can also be damaged as a result of stroke or an HIV infection, among other causes. The pain that comes from nerve damage could be the result of damage to the central nervous system (CNS), which includes the brain and spinal cord. Or it could result from damage to peripheral nerves, those nerves in the rest of the body that send signals to the CNS.
The pain caused by nerve damage, neuropathic pain, is often described as burning or prickling. Some people describe it as an electrical shock. Others describe it as pins and needles or as a stabbing sensation. Some people with nerve damage are often hypersensitive to temperature and to touch. Just a light touch, such as the touch of a bed sheet, can set off the pain.
Much neuropathic pain is chronic. Examples of pain caused by damaged nerves include:
Central pain syndrome. This syndrome is marked by chronic pain that stems from damage to the central nervous system. The damage can be caused by stroke, MS, tumors, and several other conditions. The pain, which is typically constant and may be severe, can affect a large part of the body or be confined to smaller areas such as the hands or feet. The pain often can be made worse by movement, touch, emotions, and temperature changes.
Complex regional pain syndrome. This is a chronic pain syndrome that can follow a serious injury. It’s described as persistent burning. Certain abnormalities such as abnormal sweating, changes in skin color, or swelling may be noticed in the area of the pain.
Diabetic peripheral neuropathic pain. This pain comes from nerve damage in the feet, legs, hands, or arms caused by diabetes. Individuals with diabetic neuropathy experience various kinds of pain including burning, stabbing, and tingling.
Shingles and postherpetic neuralgia. Shingles is a localized infection caused by the same virus that causes chickenpox. The rash and associated pain, which can be debilitating, occurs on one side of the body along the path of a nerve. Postherpetic neuralgia is a common complication in which the pain from shingles lasts more than a month.
Trigeminal neuralgia. This condition causes pain as a result of inflammation of a facial nerve. The pain is described as intense and lightning like, and it can occur in the lips, scalp, forehead,eye, nose, gums, cheek, and chin on one side of the face. The pain can be set off by touching a trigger area or by slight motion.
How Pain Affects Daily Life:
Pain is pervasive. According to the American Pain Foundation, 26 percent of Americans have experienced pain that persisted for more than 24 hours at one point or another, and a third of them describe their pain as disabling.
Chronic pain is strongly linked to a greatly increased risk of major mental conditions including depression, anxiety, and post-traumatic stress disorder.
A body in chronic pain continually sends stress signals to the brain, leading to a heightened perception of not only the pain itself but also the perceived level of threat.
Pain can greatly impact quality of life and functioning for those affected by it.
Chronic pain actually changes the way the brain processes emotion and the pain itself. Patients with chronic pain are more likely to experience depression because the pain acts on the sense-data areas of the brain that regulate not only emotion but also sleep. When sleep becomes unsatisfying (too long, too short, poor quality, etc.), feelings of depression, anxiety, and pain become more intense. The brain also begins to anticipate pain, leading to anxiety and a hypervigilance that is normally associated with post-traumatic stress disorder.
Just as chronic pain can lead to depression, depression itself can lead to chronic pain. This is a vicious cycle that can be very difficult to break.
For those without chronic pain, there are a good many things taken for granted. Tying shoelaces, making breakfast, walking the dog, balancing the checkbook: there is a seemingly endless supply of time, energy, and attention (TEA) for these tasks.
With chronic pain, time, energy, and attention are often in limited supply. This means that decisions must be made and priorities set daily depending on the level of pain. This is often described using spoon theory. “Spoonies” are people with chronic pain who have a limited amount of TEA for daily tasks, represented by a number of spoons. Getting dressed in the morning might take up two of that day’s ten spoons, making the rest of the day instantly problematic.
Considering the prevalence and extent of chronic pain, it’s understandable that a wide range of coping mechanisms may be part of your pain management plan. However, you might be doing yourself more harm than good, especially if you rely on tactics such as smoking, drinking, overeating, or using drugs.
Chronic pain touches every aspect of daily life, arguably none more powerfully so than in the area of relationships. Family and friends alike can be greatly affected by a loved one’s chronic pain in ways that can last long after the pain is diagnosed and treatment begins.
For chronic pain sufferers with a partner, chronic pain can be the cause of frustration with things like daily parenting and household chores. Partners of people in pain may resent the fact that they are often the primary breadwinner, main caretaker (or children and the pain patient), and head of household chores.
Financial strain is often the cause of conflict in any relationship, and chronic pain patients may incur more than their share of medical bills. Sexuality and intimacy may suffer as well, due to the pain itself and the frustrations experienced due to unequal distribution of responsibilities.
Parenting with chronic pain can be even more of a struggle, as young children don’t always understand a “boo-boo” that isn’t visible and doesn’t go away. Pain patients may not be as patient with their children as they would like. These difficult relationships with children can lead to feelings of inadequacy as a parent, which can then turn into depression or deep sadness or low self-esteem as a person and a parent.
At work, it can be difficult to feel comfortable in a setting where colleagues may resent frequent absences or what is perceived as special treatment for an invisible illness. When just getting to the job every day is a nearly insurmountable task, this resentment at work can make a chronic pain patient want to quit.
People who experience both acute and chronic pain also see impairments in working memory, attention span, mental flexibility, information processing speed, and problem solving.
Coping With Acute and Chronic Pain:
Remind yourself that you can cope with your pain
Try your best to remain calm – remind yourself of the ways you can help yourself, you could take medication designed for flare-ups
Get help with housekeeping and other chores.
Remind yourself that if you need it, you can go to the ER.
Pain can disrupt sleep on a nightly basis, and chronic pain sufferers have been known to make major lifestyle adjustments, including taking disability leave from work, changing jobs, getting assistance with activities of daily living, and even moving to a home that is more user-friendly in order to help cope with their pain.
Pain medication can be a double-edged sword.
Uncontrolled pain is a stressful experience and as the stress generates, perpetuates, and amplifies your pain. Using pain medication can both feel better and make you more likely to recover quickly.
However, pain medication can also lead to rebound pain for some. Pain medication can also cover up pain enough that you “keep going” when what your body needs is some rest and recuperation.
You may end up needing to balance these pros and cons.
Use many methods to manage your pain rather than solely relying on pain medication such as heat/ice packs, meditation, yoga, breathing techniques, or whatever is recommended for your condition.
Live Your Life
It’s easy to feel social anxiety when you’re experiencing pain. Sometimes pain will make you cry or grimace at a social function which may make you feel ashamed. While highly unlikely, people worry that will pain will become so bad that you may not be able to drive home. This is a part of the thinking of people who have panic disorder or anxiety disorder and it’s all related to being scared that you’ll lose control of your body, or trapped and unable to escape a situation.
However, avoiding social situations makes these anxieties and fears worse. So, get out there!
Re-evaluate your priorities
Many people enjoy working hard and pushing beyond what’s truly necessary. These may be self-imposed rules along the lines of “I have to get X done today.”
Break tasks into smaller tasks. Remember that many of the things you want to do are just that – wants, and just because you’d LIKE it to be done does not mean it must.
Focus upon the most basic needs and don’t feel guilty when you need help through these texts.
Experiment With What Works For You
Experiment with different types of coping to see what works for you There might be particular kinds of self-talk you find useful. That might work for you, or it might backfire. You’ll need to experiment for yourself.
Anything that involves a small amount of physical exertion and is methodical provides a helpful distraction, especially if it’s not mentally taxing.
Eating enough is important Pain makes many not hungry, but not eating is worse overall.
Enjoy lessened pain
You probably have periods when my pain was only mild rather than intense. During these moments, relax into them and enjoy the relative calm. This is a similar principle to relaxing between contractions when you’re in labor. Make sure you notice when you’re feeling good, or at least less terrible.
If you find yourself catastrophizing, consider the opposite – your pain episode might be shorter than you’re expecting. If you’re going to worry about worst case scenario, make sure to think of the best case scenario.
Pain In Different Age Groups:
Pain In The Elderly:
- Chronic pain is extremely prevalent in the elderly population.
- Addressing and treating pain in the elderly is a difficulty for health care professionals due to the following:
- The elderly are reluctant to report pain symptoms as they believe pain is a normal part of aging. The elderly may also be hesitant to “bother” their physician with complaints of pain.
- The elderly may be concerned by side effects of pain management as well as fear addiction to these drugs.
- Older adults have a higher likelihood of cognitive and sensory impairments.
- The elderly may be more concerned about the cost of treatment for pain management.
Common Pain-Inducing Conditions in Older Adults:
- Lower back pain
- Prior bone fractures
- Rheumatoid arthritis
- Paget’s disease
- Polymyalgia rheumatic
- Coronary artery disease
- Herpes zoster
- Peripheral neuropathies
- Trigeminal neuralgia
- Central post-stroke
- Nutritional neuropathies
Pain in Children:
Chronic pain is a significant problem for the pediatric population and their caregivers. The social and emotional consequences that result from pain and disabilities may be devastating. Financial costs of childhood pain may be significant in some families, as well as losing salary for time off to care for the sick child. Also, the physical and psychological issues with chronic pediatric pain can have an impact on health as well as predisposing the child for chronic pain in adulthood.
Pain Management: Treating Mind and Body
Most pain specialists stress the importance of approaching pain both physically and emotionally and addressing “people as entire human beings.” So while chronic pain medication can be effective and important for pain management for many people, it isn’t the only tool available when it comes to pain treatment, and it shouldn’t be the only tool that’s used.
Medications. There are a lot of medications that are prescribed for pain and that opioids (narcotics) and benzodiazepines may not be the best options. Those treatments have their own problems, and there are no good studies on using opioids for long periods of time for the treatment of chronic pain.
The most common way that pain is treated is with the use of pain relievers. Pain relievers may be useful for certain patients in chronic pain; however, they are not universally effective. Pain relievers may, for certain individuals, worsen their condition or cause dangerous side effects.
Short-term use for pain medications is seldom concerning, although side effects are most problematic during the initial phase of treatment and tend to diminish after long-term use.
Long-term use – and misuse – of pain medications can lead to many adverse reactions.
Addiction should be distinguished from physical dependence. Any individual that takes sufficient doses of certain types of drugs for a significant length of time can have withdrawal symptoms if the drug is suddenly stopped or reversed by another medicine. This shows the presence of physical dependence but does not constitute addiction.
Therapy. Therapy can be aimed at both the mind and the body. Your pain management team should look at any of these therapies as not being purely physical or purely psychological — we are always a mixture of both of those things.
- Physical therapy is a very important part of any pain management program. Pain can be worsened by exercise that isn’t done correctly (or interpreted incorrectly as pain rather than overuse), and a physical therapist can tailor the right exercise regimen for you. Proper exercise slowly builds your tolerance and reduces your pain — you won’t end up overdoing it and giving up because it hurts.
- Cognitive-behavioral therapy allows people to learn and have a better understanding of what the pain is from, and what they can do about it, This therapy is really about understanding the role of pain in your life and what it actually means for you.
Each person should have an individualized care plan for managing chronic pain. With the help of a doctor, each medication – the pros and cons, the benefits, other medical problems and potential side effects – should be weighed before beginning any treatment plan.
Discuss all medications and treatments with your doctor before deciding on any treatment plan.
Managing Pain with Medications:
Over-The-Counter Pain Relievers:
Over-the-counter drugs are those that may be purchased without prescriptions. The two most common types of over-the-counter pain relievers are acetaminophen and non-steroidal anti-inflammatory drugs (also known as NSAIDs).
The most important thing for individuals to remember while purchasing over-the-counter drugs is to read the labels. People must be mindful and read the labels, understand what they are taking and how much of it.
Both acetaminophen and NSAIDs reduce fever and relieve pain caused by muscle aches and stiffness, but only NSAIDs can also reduce inflammation (swelling and irritation). Acetaminophen and NSAIDs also work differently. NSAIDs relieve pain by reducing the production of prostaglandins, which are hormone-like substances that cause pain. Acetaminophen works on the parts of the brain that receive the “pain messages.” NSAIDs are also available in a prescription strength that can be prescribed by your physician.
Using NSAIDs increase the risk of heart attack or stroke and have also been known to cause stomach ulcers and bleeding. They can also cause kidney problems.
Safety And Over-The-Counter Medications:
When used sparingly, over-the-counter medications generally do not cause health problems. Occasionally, because they are drugs like any other, they are dangerous.
NSAIDs and acetaminophen are both used to prevent pain. Long-term use can lead to gastric bleeding, kidney failure, liver failure, as well as other conditions.
The most concerning over-the-counter pain medication is acetaminophen, which – even at fairly low doses – can be toxic to the liver, especially for those who have liver problems or are heavy drinkers.
Prescription Pain Killers
Chronic pain management is a public health concern with significant increases in the use of opioids for pain relief. There is a corresponding growth in the number of opioids prescribed in the U.S. and the overdose from those drugs. Family physicians and other primary care providers play a vital role in balancing patients’ pain management needs with the risk of drug misuse and abuse.
The American Academy of Family Physicians (AAFP) is dedicated to finding solutions to the crisis of pain management and opioid abuse. We recognize that long-acting and extended-release opioids are powerful drugs that require oversight, but these drugs can be controlled without unduly limiting their proper use. Creating additional prescribing barriers for primary care physicians would limit patient access when there is a legitimate need for pain relief.
What opioid medications do
Opioids are a broad group of pain-relieving drugs that work by interacting with opioid receptors in your cells. Opioids can be made from the poppy plant — for example, morphine (Kadian, Ms Contin, others) — or synthesized in a laboratory.
When opioid medications travel through your blood and attach to opioid receptors in your brain cells, the cells release signals that muffle your perception of pain and boost your feelings of pleasure.
When opioid medications are dangerous
What makes opioid medications effective for treating pain can also make them dangerous.
At lower doses, opioids may make you feel sleepy, but higher doses can slow your breathing and heart rate, which can lead to death. And the feelings of pleasure that result from taking an opioid can make you want to continue experiencing those feelings, which may lead to addiction.
You can reduce the risk of dangerous side effects by following your doctor’s instructions carefully and taking your medication exactly as prescribed. Make sure your doctor knows all of the other medications and supplements you’re taking.
People with chronic pain will often initially consult their family physician for treatment. Treatment may include subspecialists, but it is often the family physician’s role to coordinate and manage care, including the use of opioid pain relievers. The AAFP views the goal of pain management to be primarily improvement and maintenance of function. We urge family physicians to individualize treatment based on a review of a patient’s potential risks, benefits, side effects, and functional assessments, and to monitor ongoing therapy accordingly.
Invasive Pain Interventions:
Viscosupplementation – lubricating substances are injected into the knee joint in patients suffering from osteoarthritis of the knee. These substances restore lubrication of the joint and decrease pain while increasing motility.
Intra-Articular Steroid Injections – for those suffering osteoarthritis, steroid injections may be injected into the joint for short-term relief.
Spinal Cord Stimulation – a small device is implanted under the skin – usually in the abdomen or buttocks – to deliver mild electrical signals to an area near the spine. The electrical signals can be adjusted by the patient via remote control to provide optimal pain relief.
Epidural – a steroid is injected into the epidural space in the neck or lower back, with or without a numbing agent.
Nerve Blocks – combination of local anesthetic and steroids used diagnostically to identify pain generators. These can also therapeutically blog a painful condition, although only for the short-term.
Rhiztomy – a probe is inserted to destroy the nerve that supplies the facet joint (a small joint that connects the back of the spine and cause neck or back pain).
Intrathecal Drug Delivery Systems – also known as pain pumps, these implanted devices deliver prescribed amounts of pain medication directly to the spinal cord and nerve roots.
Non-Invasive Pain Interventions:
Acupuncture – thin, metallic needles are inserted along acupuncture sites on the body to restore balance. These needles are manipulated or stimulated electrically and has gained a wide following of chronic pain sufferers.
Hyperbaric Oxygen – oxygen is administered in a pressurized chamber to increase the oxygen delivery to the tissues, but its efficacy is still largely undetermined.
Passive Therapies – passive therapies, such as massage, ultrasound, heating pads, and wax treatment or traction, can be useful for managing short-term pain but have limited benefit in chronic pain conditions.
External Stimulation Devices – a common device used to treat chronic pain is transcutaneous electrotherapy (TENS), in which electrical stimulation is applied to the surface of the skin.
Trigger Point Injections – a short-term solution for those with myofascial pain syndrome.
Monotherapies to Manage Chronic Pain:
Education – Patient and family education should be the primary focus of treatment and management of chronic pain conditions. It is crucial that the healthcare team work in conjunction with the family to develop strategies to cope with and manage chronic pain.
Exercise – The treatment for chronic pain almost universally suggests that the patient with chronic pain be kept as active as possible. The overwhelming evidence suggests that exercise programs are beneficial to those who suffer chronic pain.
Psychological Approaches – While talking to someone trained in “talk therapy” will not cure chronic pain, it can aid in the development of coping strategies to manage and fully live life.
Mind-Body Approaches – There are many mind-body approaches to living with chronic pain, including meditation, relaxation, hypnosis, biofeedback and imagery.
Chronic pain, while a difficult and frustrating condition to manage, is something unique to each individual, which means that each person will respond uniquely to differing approaches to chronic pain. The most important things for those in pain is to advocate for themselves and not be afraid to stand up for a treatment that isn’t working.
Additional Pain Resources:
Clinical Trials for Pain may be utilized for certain individuals who meet the standards for participation.
Drug Interactions Checker – a handy way to determine the interactions between medications.
Drug Identification Checker – useful way to identify prescription medications.
FDA Website for safety information about prescription drugs.
Information about over-the-counter medications.
Physician’s Desk Reference – excellent source of drug information.
RX List – comprehensive internet drug index.
International Association For The Study of Pain (IASP) is a scientific organization open to all professionals involved in the research, diagnosis or treatment of pain.
American Academy of Pain Medicine (AAPM) is a medical specialty society for physicians who practice in the field of pain medicine. The organization provides education, training, advocacy, and research in the specialty of pain medicine.
Page last updated 8/2018