Atropine is a tropane alkaloid found in plants in the Solanaceae family. Atropine is an anticholinergic compound that also exhibits analgesic and antinociceptive activity. Atropine is a competitive inhibitor of muscarinic acetylcholine receptors (mAChRs) that is commonly used for ophthalmic treatments such as initiating mydriasis. Atropine displays cardiostimulatory/positive inotropic activity as well, increasing heart rate by inhibiting vagal nerve activity. In animal models of thermal pain, atropine exhibits analgesic activity; in other animal models, atropine inhibits histamine-induced increases in thromboxane A2 (TxA2) levels.