Opioid Antagonists

Opioid antagonists, also known as opioid receptor antagonists, are receptor antagonists that act on the opioid receptors in the human brain. These drugs work by attaching themselves on opioid receptors much more tightly than a regular opioid drug would. However, they are beneficial in the sense that they do not cause the same adverse effects that arise when you use or abuse opioids.

Taking opioid antagonists, to this end, can effectively block the pleasurable effects of abusing drugs like heroin and morphine. For this reason, many emergency medical departments use opioid antagonists to reverse opioid overdose effects. In these situations, the centers would use the opioid antagonists for a short time period of the primary reason of saving the overdose victim’s life.

However, opioid antagonists can also be applied as part of an opioid addiction treatment program. Here, doctors would recommend that you use opioid antagonists such as buprenorphine because they act as partial agonists for the opioid receptors in the brain.

Types of Opioid Antagonists

The opioid antagonists that are most commonly used in the treatment of addiction and in the reverse of drug overdoses include but are not always limited to:

  • Alvimopan
  • Axelopran
  • Bevenopran
  • Buprenorphine
  • Cyprodime
  • Dezocine
  • Levallorphan
  • Methylnaltrexone
  • Methylsamidorphan
  • Naldemedine
  • Nalmefene
  • Nalodeine
  • Nalorphine
  • Nalorphine dinicotinate
  • Naloxegol
  • Naloxone
  • Naltrexone
  • Naltrindole
  • Norbinaltorphimine
  • Samidorphan

Opioid Antagonists and Withdrawal Effects

If you are suffering an opiate overdose and you receive a prescription for opioid antagonists, the side effects that will arise would typically not be the main concern for the doctors.

However, taking some of these drugs – especially naloxone – could cause you to go into immediate withdrawal mode. This means that you will experience tremendous opiate output from your sympathetic nervous system.

As a result, you are likely to display the following withdrawal effects:

  • Cardiac arrest
  • Diarrhea
  • Heart arrhythmias that might be threatening to your life
  • High blood pressure
  • Muscle aches
  • Muscle pains
  • Nausea
  • Racing heart
  • Restlessness
  • Severe abdominal cramping
  • Sweating
  • Vomiting

Luckily, most of these opioid antagonist side effects tend to last in the short term. However, if you experience arrhythmias, they might turn out to be life-threatening or even fatal.

Side Effects of Opioid Antagonists

If you use opioid antagonists in chronic doses, there is a high risk that you might suffer some adverse side effects. For instance, if you have been using naltrexone on a daily basis while trying to manage your opioid or alcohol dependence, you could suffer the following side effects:

  • Vomiting
  • Syncope (or passing out)
  • Sleeplessness
  • Nervousness
  • Nausea
  • Muscle aches
  • Joint aches
  • High levels of muscle enzymes inside the blood
  • Headache
  • Elevated liver enzymes
  • Dizziness
  • Diarrhea
  • Decreased energy
  • Decreased appetite
  • Anxiety
  • Abdominal pain
  • Abdominal cramping

To this end, the FDA – the Food and Drug Administration – recommends that you should only use these drugs in the short term. By so doing, you could potentially avoid some of the adverse side effects of opioid antagonists.