Opioid Pain Medication List
In this next section, we will discuss the multiple different types of opioid medications.
There are different receptors and indications for their use in this section we'll discuss opioid medications.
Opioids are a large class of molecules that are actually polypeptides. The way they work is by increasing analgesia, which is equal to increased pain tolerance and decrease perception and reaction to pain.
Opioid receptors are g-protein coupled receptors. They have multiple subtypes like:
- Mu -receptors;
Mu receptors are the most important for pain control because they bind morphine. Some drugs may activate one receptor subtype and antagonize another receptor subtype.
In the opioid receptor's family, the mu-receptor is responsible for many of the wanted and unwanted effects of opioids. By activating this receptor you can experience:
- respiratory depression.
Whereas the activation of the kappa-receptor, for example, can cause dysphoria, analgesia, and sedation.
Opioid drugs vary by their properties, their ability to produce pain control and side-effects.
The prototype of opioid medication currently is Morphine. It is considered a full agonist at the MU-receptor and it causes maximum pain relief.
Remember, the adverse effects of opioid drugs may include respiratory depression. Opioid drugs can also classically cause constipation, nausea, and vomiting. They have a high abuse potential as well.
The triad of opiate intoxication includes miosis (constricted pupils), respiratory depression, and coma. When the patient comes into the emergency room displaying these side-effects, you should immediately think about opioid overdose. Most patients that exhibit the side of these symptoms should receive Narcan or an opioid antagonist to release the opioid medication from the receptor.
Most Popular Opioid Drugs
Naloxone or Narcan is an opioid antagonist and full mu- opioid antagonist. It will displace morphine from that receptor.
The opioid antagonist, such as Narcan, are used very commonly in either suspicion or actual known opioid overdoses. They can actually trigger a withdrawal symptom symptoms in some patients. The drug is related to naloxone or Narcan. It is often used in alcohol craving situations and it's used for alcoholic patients.
There are other uses for opioids, besides simply pain control. Imodium and Lomotil are commonly used to treat diarrhea, because of the ability of these opioids to slow down the gut.
Diphenoxylate is commonly given along with atropine as the combo pill Lomotil, which works very well in patients that have irritable bowel syndrome.
Opioids can also be used to treat cough, as we see with the medications codeine and dextromethorphan.
Codeine is classic for causing constipation. Codeine is actually converted to morphine in the body.
Again morphine is the prototype opioid analgesic. It has low bioavailability, that is why its much stronger when given intravenously. The active metabolite is morphine-6-glucuronide, which has glucuronic molecules that are an active metabolite. It also contributes to analgesia and is possibly nephrotoxic.
Codeine is also known as methylmorphine. It is metabolized to morphine by a CYP2D6 enzyme. Patients that do not have a strong level of this enzyme in their body, do not get a therapeutic effect from Codeine.
It is less effective than morphine and its found in some cough suppressants.
Other opioid medications that you should be aware of include Oxycodone and Oxycontin. These are medications that are semi-synthetic. They are intended for chronic pain treatments. These can be formulated either alone or in combination with either Tylenol or acetaminophen or aspirin. These pills are often commonly given to patients that have chronic pain and these patients will take extended-release pills.
Vicodin or hydrocodone is a medication that is very commonly prescribed today in America. It is a short-acting opiate that's usually formulated with acetaminophen, but it can also be formulated with NSAID. It is very popular for short-term pain control, but it can have all of the side effects that we see in other opiates.
Fentanyl is another very short-acting synthetic opioid. It is very potent. It is about a hundred times more potent than morphine gram to gram. Fentanyl is very effective because it can be given transdermally or intravenously. It has quick on and quick off properties. The drug is widely used in an anesthesia situation. In the intensive care unit, when a patient is about to be intubated or has already been intubated and needs to be sedated a lot often times we will give fentanyl along with the benzodiazepine in order to achieve pain control and sedation.
Demerol is another popular opioid analgesic that has become less popular these days mostly because of its abuse potential. It also creates in the body a toxic metabolite, knowт as normeperidine, which can cause seizures and can be fatal.
All opioids run the risk of developing tolerance independence. Withdrawal from opiates can also be very severe. Classically these patients develop:
- goose bumps;
- hot and cold flashes;
- muscle cramps;
- GI distress including diarrhea.
Another medication you should be aware of is the partial agonist buprenorphine. This medication is commonly given to patients that have open dependence and withdrawal. The typical analgesic effects can be seen in naive individuals and it may also trigger a withdrawal in patients that are taking an opioid agonist such as morphine.
Other opioids you should be aware of our methadone, which has a long half-life. It is commonly used in rehabilitation of heroin abusers. It prevents the withdrawal syndrome, but it does not cause as much of a high as heroin does. Users of methadone will not test positive on a drug screen.
Propoxyphene is a less commonly given opioid. It is weaker than Codeine in terms of its pain control, but it is more toxic. It is part of the pill called Darvocet, when its given along with acetaminophen. This medication is not commonly given in the United States.