Opioids: Opioids occur naturally in the body as a means of mediating painful stimuli. They work by attaching to Nocciceptors (pain receptors), and inhibiting the influx of calcium through gated channels in the neurons responsible for pain transmission. The result is that those neurons don't fire, and the pain signal is diminished. This slows CNS conduction, which is fine at therapeutic levels. However, when excessive amounts of an opioid are introduced to the body, the disruption in CNS conduction becomes a big problem; particularly due to the depression of the respiratory drive, decrease in HR, and alterations in LOC.This occurs because opioid receptors are not just found on pain receptors, but are also located on all CNS neurons.
Patients usually present with:
Altered LOA
Constricted pupils
Respirations <10/min
Often Tachycardia, but brady if the dose is very high
Slowed motor response
Possible hypotension.
Treatment: Establish a patent airway, provide PPV if respirations are inadequate, and administer Naloxone ASAP to a level that restores respiratory drive.
Stimulant overdoses: This includes drugs like cocaine, methamphetamines, MDMA, etc. These drugs work by attaching to adrenergic receptors, and stimulating production and activity of EPI/Norepi, Serotonin and dopamine in the CNS. This activates a profound sympathetic response that drives the body into “fight or flight mode”. Serotonin activity leads to euphoria, while dopamine, epi, and norepi trigger alpha and beta responses in the cardiac system, musculoskeletal system, and neurological system. Stimulants such as cocaine work by blocking the reuptake of sympathetic neurotransmitters, which prolongs their effects in the CNS. It also blocks Na+ channels in the heart, which prolongs the QRS. This can present with a host of problems including MI, CVA, Rhabdomyolysis, hyperthermia, dehydration, seizure, coma, and death.
These patients present with:
Agitation/delirium/Psychosis
Tachycardia/Tachydysrhythmia
HTN
Seizures
Violent behaviour and increased strength
Decreased pain sensation
Secondary injuries are common
Treatment at the PCP level is somewhat limited. Ensure your safety, address ABCs, get an IV if possible, and monitor heart rhythms. At the ACP level, a benzodiazepine can be used to reduce CNS stimulation.
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