An analysis of some different types of pain medication and their uses and effectiveness.
Written by: Kavya, Akshaya, Haritha
Pain medication is one of the most important types of medication used today. Whether people are looking for relief from a headache, recovering from surgery or battling cancer, the need for pain medication remains a common ground. In this article, we describe three common types of pain medications: opioids, anesthetics and non-steroidal anti-inflammatory drugs (ibuprofen).
The information below is not a substitute for professional medical advice. Content meant for education purposes only.
Opioids
What are opioids?
Opioids are a class of drugs that are derived from naturally occurring substances found in the opium poppy (Papaver somniferum) plant (6). These drugs are commonly known as ‘narcotics.’ Opioids contain chemicals that relieve severe pain in the body. They can either be obtained from plants or be made synthetically in the laboratory. Common opioids that are naturally occurring opioids are morphine and codeine (6). Heroin, an illicit narcotic drug, is synthesized from naturally occurring opioids like morphine (6). Other opioid drugs that are completely synthesized in the laboratory include meperidine and fentanyl (6). Opioids are the strongest known painkillers.
Papaver somniferum, the opium poppy plant (1).
When and how are opioids administered?
Opioids are typically taken by patients with chronic headaches and backaches, those that are experiencing severe pain from battling advanced stages of cancer, or those that are recovering from surgery. They are also taken by those that have been severely injured after an accident (7). Opioids are commonly administered by an injection or an IV or can be taken as lozenges. Some are also administered through a skin patch. The dosage and form of administration depends on the patient, their situation as well as their level of pain. Commonly prescribed opioids are morphine, codeine and fentanyl. Heroin is an illegal opioid and is not authorized for prescription as a medication (7).
Side effects, Addiction and Withdrawal
Opioids bind to certain proteins called opioid receptors found on the spinal cord, brain, intestine and other parts of the body. When this binding occurs, the opioids block pain signals to the brain thereby effectively relieving pain (7). Because of this, opioids can cause addiction and serious side effects which can be life-threatening. Some major side effects include:
Shallow breathing
Lowered heart rate
Loss of consciousness
Opioids also tend to cause addiction in those who take the drug. Opioid addiction is estimated to occur in one in every four individuals on prescription medication (12). Additionally, addiction occurs especially when patients are on long term opioid drug therapy for chronic pain management (7). Opioids trick the body into thinking it cannot survive without the drug. This happens because neurons adapt so that they function properly only in the presence of the drug (5). If stopped suddenly, severe withdrawal symptoms occur within hours. Common side effects of withdrawal while stopping the medication include:
Anxiety
Drug Cravings
Insomnia
Abdominal pain
Vomiting and diarrhea
Tremors
Since these effects are often serious, physicians reduce the dosages gradually so that the body can adapt to decreasing amounts of the drug in the body (7).
Before starting a drug therapy that involves opioids, it is, therefore, important to consider alternative therapies. A lot of the time, opioid therapies are combined with non-opioid drugs so that the dosage of the opioid drug can be lowered. Many patients prefer to try acupuncture, meditation and massage therapies first. Sometimes, local anesthetics are also used to relieve muscle spasms or nerve pain (7). Opioids are used as the last resort.
Opioids bind to opioid receptors in the body and mimic a natural compound in the body. They can cause addiction and severe withdrawal effects (2).
Opioid Crisis
In the late 1990s, physicians began prescribing opioids at a greater rate as pharmaceutical companies who manufactured these drugs assured them that patients would not get addicted to this class of drugs. However, as the rate of prescription increased, the rise of illegal drug use also increased to a point where it became clear that addiction was rampant (11). In 2017, more than 47,000 deaths were caused in the United States due to opioid overdose, including prescription drugs and illicit drugs such as heroin (11). 1.7 million people suffered from disorders related to prescription opioid use (11). This issue is a public health crisis especially because opioid addiction has lead to an increase in neonatal abstinence syndrome (babies born to mothers who have misused opioids during pregnancy are born with withdrawal symptoms) as well as an increase in diseases such as HIV and hepatitis, which are spread by using infected injection needles (11). Additionally, about 21-29% of people who are prescribed opioids misuse them; 8-12% develop an opioid use disorder; 4-6% of those who misuse prescription opioids eventually begin using heroin; and 80% of heroin users have misused prescription opioids (11).
"21-29% of people who are prescribed opioids misuse them; 8-12% develop an opioid use disorder; 4-6% of those who misuse prescription opioids eventually begin using heroin; and 80% of heroin users have misused prescription opioids"
In response to the crisis, medical research centers like the National Institute of Health are promoting the use of overdose reversing drugs, increasing awareness and access to treatment and recovery services, providing support for research, advancing better pain management options, and promoting better public health surveillance to increase our understanding of this endemic (11).
Pictured above is Naloxone, a drug used for opioid overdose-reversal (3).
Opioids vs Cannabis for pain
Cannabis, also known as marijuana, is a plant containing chemicals called cannabinoids. These bind to cannabinoid receptors in the brain, whereas opioids bind to opioid receptors. Opioid receptors are concentrated in the spinal cord, the limbic system and the brainstem. The brainstem contains the medulla which is responsible for involuntary functions such as breathing and heart rate. Cannabinoid receptors are concentrated in the ganglia, hippocampus and cerebellum. These regions control aspects such as memory, motor control and the autonomic nervous system. They do not control involuntary functions. As a result, overdose of cannabis can cause headaches, nausea and paranoia, but not death. Overdose of opioids, however, causes death (12). Both cannabis and opioids are good options for pain management. However, the federal government lists cannabis as a ‘Schedule 1’ drug and opioids as ‘Schedule 2’ drugs. This essentially means that cannabis is not recognized to have any medicinal value and has a great potential for misuse. Opioids are recognized to have more medicinal value and are easier to obtain and use (12). As a result, opioids are prescribed over cannabis for pain management.
Anesthetics
Anesthetics have revolutionized medical procedures enabling medical professionals to save countless lives (4).
Most of us have probably encountered some form of an anesthetic drug in our lives. Whether it was used for a wisdom tooth removal or a surgery, anesthetics have enabled humans to perform robust, life-saving procedures. Before anesthetics were administered, people were often intoxicated before undergoing a painful procedure. It was also common to use a concoction of opioids and herbs to alleviate pain. Anesthesia, in its early modern form, was first used at Massachusetts General Hospital, Boston by a dentist William T.G. Morton and surgeon John Warren (10). They had used sulfuric ether as the anesthetic. Morton labeled it Letheon, in reference to the mythological Lethe River that removes painful memories (10).
Types of anesthetics, their administration, and side effects
When it comes to anesthetics, there are four different categories: General anesthesia, Regional anesthesia, Local anesthesia, and IV/Monitored sedation.
General anesthesia: this refers to the anesthetic administered while undergoing surgeries that require the patient to be unconscious (hip, heart, etc.) (8). This anesthetic slows down most processes in the body and requires the attention of an anesthesiologist. To ensure that vital body functions are occurring, a breathing tube, among other life supporting machines, may be used. General anesthesia is reversed after the procedure (8). Side effects of general anesthesia may include nausea, sore throat (from ventilation tube), confusion, muscle pain, hypothermia (9). General anesthesia typically has more negative side effects out of the different types of anesthetics administered and in rare cases, can result in death (9). It is important to notify your doctor if you notice any allergic reactions to any type of anesthetic administered.
Regional anesthesia: this type of anesthesia works on a large portion of the body. Regional anesthesia is administered through a catheter or an injection where the procedure requires the patient to be awake (8). This includes spinal blocks and epidurals. Epidurals are used commonly for labor and delivery. Spinal blocks are used for surgical procedures such as C-sections. Side effects may include headache, minor back pain, and nerve damage (9).
Local anesthesia: refers to the type of anesthesia that is used to numb a small region of the body. It is most commonly administered through an injection for procedures such as biopsies and stitches (8). Local anesthesia rarely has any negative side effects and might result in temporary soreness (9).
IV/Monitored sedation: administration of sedation medications relaxes the entire body and can cause a person to fall asleep. Conscious sedation is usually administered for minor surgeries (8). These anesthetics are used commonly for a wide-range of procedures including outpatient procedures. With sedation, the patient will never be unconscious as with general anesthesia. Monitored sedation is given through an IV and can range from minimal, moderate, to deep levels (8). Side effects of sedation can include headache, nausea, drowsiness, difficulty in urination, and more rarely pneumothorax (lung collapse) or nerve damage (9).
IV drips are used to administer analgesia during monitored sedation (5).
Mechanism of action
Local anesthetics are able to relieve pain by blocking neurotransmission locally. The medication blocks a specific ion channel (sodium) which is necessary for sending nerve impulses. Therefore, this only affects the neurotransmitters in that region.
Pictured here are two neurons. The stop sign represents the medication that blocks the signal from continuing to the brain (6).
The mechanisms of general anesthetics, on the other hand, are a little more ambiguous. Most of the general anesthetics are administered through inhalation. These anesthetics target the central nervous system where they interfere with the neurotransmitter signaling pathway. Specifically, these inhalation anesthetics target the lipid components of the cell membrane rather than water soluble ones. These volatile anesthetics have low affinity for their binding sites (receptors) on the cells (15). In other words, the medication does not easily bind to its target. Therefore, high concentrations are needed in order to ensure that they bind to the receptors on the neurons. Structural and genetic research are being conducted in order to study the details of how general anesthetics work.
NSAIDs (Nonsteroidal anti-inflammatory drugs)
Prescription of NSAIDs (7).
What are NSAIDs?
NSAIDs, or Nonsteroidal Anti-Inflammatory Drugs, are used to treat chronic pain as well as inflammation. These drugs are typically given for treatment to reduce pain in the back, neck, and muscle (2). NSAIDs are fairly well-known among the general population, as they are the “most widely prescribed drugs in the world,” (4). Individuals take NSAIDs when consuming pain relieving medicines which are used for general pain, such as aspirin. Some examples of NSAIDs are Ibuprofen (Advil) and Naproxen sodium (Aleve), which can be given over-the-counter when consuming non-prescription strength amounts (3). The over-the-counter versions of these drugs are less strong in dosage than prescription NSAIDs. NSAIDs are known to relieve pain and reduce fevers, but they also contain anti-inflammatory properties, and are typically for short-term use. The different types of NSAIDs can be organized into groups based on their chemical characteristics, selectivity, and half-life, and are created from either acetic acid, anthranilic acid, enolic acid, or propionic acid (4). The over-the-counter NSAIDs, as we mention, can be categorized into aspirin compounds (Anacin, Bufferin), ibuprofen (Motrin, Advil), and Naproxen sodium (Aleve, Naprosyn) (4).
Before using these drugs, it is important to learn about the process in which they are administered and generally used (how much to consume, how often, etc.). As we have done with the medications mentioned above, we will discuss their side effects as well. As these drugs are fairly common in administration, NSAIDs are prescribed to about 60 million people every year, and lead to 41,000 hospitalizations and 3,300 deaths among older adults every year (4).
The chemical structure of Ibuprofen, a NSAID (8).
When and how are they administered?
Let’s delve into what specifically, NSAIDs are used to treat. Other than helping cope with a fever by reducing its effects on the individual and being used to relieve aches from colds, these drugs are used for dental pain, menstrual cramps, and other muscle and back aches. Additionally, they can help with Rheumatoid Arthritis (RA), Osteoarthritis, and Tendonitis (3). For RA, higher amounts of NSAIDs are typically prescribed, as this condition can lead individuals to experience swelling, redness, and stiffness of their joints (3).
Administration of NSAIDs is not usually given to older adults, as you will read about further below, as well as those with certain chronic illnesses such as asthma, since these drugs can lead to allergic reactions. For adolescents, it is important that NSAIDs are not administered to those who have had chickenpox or influenza, which can lead to problems in the liver (Reye’s syndrome) (13). They should be given for the shortest amount of time possible, and should only be taken at the amount prescribed. In terms of prescription, different dosages are given based on the individual’s specific condition. Additionally, the drugs may have to be taken from 1 to 4 times per day, and sometimes, different NSAIDs need to be tried out before finding the right one for you (3). Doctors are able to prescribe a certain NSAID by looking at the risks and effectiveness of the drugs, and your medical history. There are NSAIDs which individuals can take from slow-release or as a patch or gel (4). Typically though, NSAIDs are given orally to control acute and chronic pain, and have been shown effective to those with postoperative pain. NSAIDs such as Diclofenac (which are given post-surgery to adults to reduce pain), can be given through IV, especially for those who can’t take the drugs orally (14). As NSAIDs are common and are being researched, better drug-delivery systems will likely provide other options for individuals who need to take these drugs in the future.
Mechanism of action
NSAIDs restrict the body from producing the chemicals which are associated with pain and inflammation (4). In order to effectively reduce pain, NSAIDs block enzymes in your body, and we can categorize these drugs separately based on which of these enzymes they block. Certain NSAIDs block both COX-1 and COX-2, which are produced for different reasons (COX-1 is an enzyme that protects the stomach and intestinal lining, as well as aids in kidney function, whereas COX-2 is an enzyme created when your joints are injured) (4). Nonselective NSAIDs, like Ibuprofen and Aspirin, are the drugs which block against both types of COX (cyclooxygenases), but NSAIDs which block only COX-2 have been known to reduce issues with stomach problems. The prostaglandins, which NSAIDs block production of, have many other effects on the body other than prompting pain, fevers and inflammation. They are involved in protecting the mucosal lining and helping kidney function (2). Because of this, the suppression of prostaglandins have many different effects on our bodies, both beneficial and harmful.
Side effects
NSAIDs have several side effects that you should be made aware of before using, similar to most other drugs. Generally, common side effects include feeling symptoms in the gastrointestinal area, such as feeling bloated, having gas, and experiencing nausea, as well as stomach pain (3). Some people may also experience dizziness and difficulty with concentrating, along with headaches (3). Studies have shown that long-term use on older adults have led to an increase of risk for peptic ulcers and stroke and heart disease (4). Apart from certain groups of individuals, including older people and those with chronic illnesses, who can have higher risks for side effects from these drugs, others can experience mild side effects.
We can examine several of these side effects by categorizing them based on the different parts of the body which are affected by the intake of the drugs. We will look over a few of these side effects, starting from the potential effects in the stomach region. It is possible to feel irritation or pain, heartburn, have diarrhea or constipation, as well as bleeding and ulcers, due to the consumption of NSAIDs, but these effects can be reduced by taking in food, milk, or antacids (blocks production of acid) (4). NSAIDs can increase blood pressure, as well as lead to heart attack and stroke (excluding aspirin), which you are at a higher risk of having the longer you take these drugs. In terms of allergic reactions, NSAIDs can lead to having swollen lips, tongue, or eyes, as well as experiencing shortness of breath (4). There are also different side effects one can face when using non-aspirin NSAIDs. These side effects have been mentioned above, but it is important to note that non-aspirin NSAIDs in particular, can increase the risk of heart attacks/strokes, which can happen in the first few weeks of taking the drug (3).
Modern medicine has relied heavily on pain medications. Different pain medications are used depending on the severity and complexity of the procedure. We hope that this post has been informative of some of the common pain medications, and the pros and cons of each. Before taking any sort of medicine, it is important to understand the effects they can have on our bodies, and consult with the professionals thoroughly.
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