Differential
It may not be possible to tell the difference between beta blocker toxicity and calcium channel blocker overdose based on signs and symptoms. Management
The medical management of CCB toxicity may be difficult. It may not improve with the usual treatments used for a low blood pressure and a slow heart rate. In those who have no symptoms or signs six hours following taking an immediate release formulation and 24 hours after taking an extended release formulation need no further medical treatment. Detoxification
Activated charcoal is recommended if it can be given within an hour or two of taking the calcium channel blockers. In those who have taken an extended release formulation of a CCB but are otherwise doing fine, whole bowel irrigation with polyethylene glycol may be useful. Causing vomiting by the use of medications such as ipecac is not recommended. Insulin
High doses of intravenous insulin with glucose may be useful and are a first line treatment in overdoses. As this treatment may cause a drop in blood sugar and blood potassium levels, these should be monitored closely. Other
Intravenous calcium gluconate or calcium chloride is considered a specific antidotes. Slow heart rate can be treated with atropine and sympathomimetics. Low blood pressure is treated with vasopressors such as adrenaline.There is tentative clinical evidence and good theoretical evidence of the benefit of lipid emulsion in severe overdoses of CCBs. Methylene blue may also be used for those with low blood pressure that does not respond to other treatments.
Similarly, selective serotonin reuptake inhibitors can cause mydriasis. Dissociatives such as dextromethorphan (an SSRI and sigma-1 agonist). Certain GABAergic drugs, such as phenibut and GHB. Adrenergic agonists, such as phenylephrine and cyclomydril. Adrenergic agonists may be used if strong mydriasis is needed in surgery. Norepinephrine is a hormone and neurotransmitter that regulates the involuntary muscles of the autonomic nervous system, including dilation of the pupil aperture via the muscles of the iris. Hence adrenergic agonists mimic the activity of norepinephrine, which is how they induce mydriasis.Natural release of the hormone oxytocin can cause mild to moderate mydriasis.Long term effects of drugs can also cause mydriasis, for example opioid withdrawal. Autonomic neuropathy
Parasympathetic fibers travel with cranial nerve III, the oculomotor nerve, to innervate the circular layer of muscle of the eye (sphincter pupillae). Damage to this nerve typically manifests itself as mydriasis, because the sympathetic supply to the pupil, which causes mydriasis, remains unaffected, and therefore unopposed. Multiple central nervous system disorders e.g. epilepsy, stroke, and impending brain herniation are known to lead to temporal mydriasis as well. A brain catastrophe, or a rapidly increasing brain mass, can cause compression of the oculomotor nerve. Trauma
In cases of head injury or orbit trauma (eye injury), the iris sphincter (the muscle responsible for closing the pupil) or the nerves controlling it can be damaged, reducing or eliminating the normal pupillary light reflex. References


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