💊 Morphine is considered the classic opioid analgesic with which other painkillers are compared. Like other medications in this class, morphine has an affinity for delta, kappa, and mu-opioid receptors.
💊 This drug produces the majority of its analgesic effects by binding to the mu-opioid receptor within the central nervous system (CNS) and the peripheral nervous system (PNS).
💊 Morphine can potentially be a lethal medication when not used properly. It causes a host of symptoms related to depression of the CNS. Severe respiratory depression is the most feared complication of morphine in cases of overdose. Immediate injection of naloxone is required to reverse the effects of morphine.
Tricyclic antidepressants (TCAs) are drugs used to treat depression, bipolar disorder, and other conditions such as chronic pain and insomnia. They primarily work by blocking norepinephrine and serotonin (5HT2) reuptake. They also block acetylcholine and histamine receptors which contribute to their side effect profile.
👉🏻 Muscarinic M1 block: anticholinergic side effects including dry mouth, blurry vision, constipation, and urinary retention
👉🏻 Histamine 1 receptor block: sedation and weight gain
👉🏻 Adrenergic alpha block: postural hypotension, tachycardia, and erectile disfunction
👉🏻 Sodium channel block: QTc prolongation, arrhythmias
👉🏻 Serotonin uptake block: weight gain