Olopatadine, sold under the brand name Opatanol among others, is a medication used to decrease the symptoms of allergic conjunctivitis and allergic rhinitis (hay fever). It is used as eye drops or as a nasal spray. The eye drops generally result in an improvement within half an hour.Common side effects include headache, sore throat, eye discomfort, change in taste. More significant side effects may include sleepiness. It is unclear if use during pregnancy or breastfeeding is safe. It is an antihistamine and mast cell stabilizer.Olopatadine was patented in 1986 and came into medical use in 1997. It is available as a generic medication. In 2017, it was the 270th most commonly prescribed medication in the United States, with more than one million prescriptions. Side effects
Some known side effects include headache (7% of occurrence), eye burning and/or stinging (5%), blurred vision, dry eyes, foreign body sensation, hyperemia, keratitis, eyelid edema, pruritus, asthenia, sore throat (pharyngitis), rhinitis, sinusitis, taste perversion, and vomiting. Chemistry
Synthesis
Pharmacology
Pharmacodynamics
Olopatadine acts as a selective antagonist of the histamine H1 receptor, thus stabilizing mast cells and inhibiting histamine release. History
Olopatadine was patented in 1986 by Kyowa Hakko Kogyo and came into medical use in 1997.In the United States, Pataday Twice Daily Relief was first approved by the FDA in 1996, under the name Patanol as a prescription drug and was indicated for the treatment of the signs and symptoms of allergic conjunctivitis (referring to ocular redness and itching due to allergies).
Pathology
Adrenal tumors are often not biopsied prior to surgery, so diagnosis is confirmed on examination of the surgical specimen by a pathologist. Grossly, ACCs are often large, with a tan-yellow cut surface, and areas of hemorrhage and necrosis. On microscopic examination, the tumor usually displays sheets of atypical cells with some resemblance to the cells of the normal adrenal cortex. The presence of invasion and mitotic activity help differentiate small cancers from adrenocortical adenomas. Several relatively rare variants of ACC include:
Oncocytic adrenal cortical carcinoma
Myxoid adrenal cortical carcinoma
Carcinosarcoma
Adenosquamous adrenocortical carcinoma
Clear cell adrenal cortical carcinoma

Differential diagnosis
Differential diagnosis includes:
Adrenocortical adenoma
Renal cell carcinoma
Pheochromocytoma
Hepatocellular carcinomaAdrenocortical carcinomas are most commonly distinguished from adrenocortical adenomas (their benign counterparts) by the Weiss system, as follows:
Total score indicates:
0-2: Adrenocortical adenoma
3: Undetermined
4-9: Adrenocortical carcinoma

Treatment
The only curative treatment is complete surgical excision of the tumor, which can be performed even in the case of invasion into large blood vessels, such as the renal vein or inferior vena cava. The 5-year survival rate after successful surgery is 50–60%, but unfortunately, many patients are not surgical candidates. Radiation therapy and radiofrequency ablation may be used for palliation in patients who are not surgical candidates. Minimally invasive surgical techniques remain controversial due to the absence of long-term data, with a particular concern for rates of recurrence and peritoneal carcinomatosis.Chemotherapy regimens typically include the drug mitotane, an inhibitor of steroid synthesis, which is toxic to cells of the adrenal cortex, as well as standard cytotoxic drugs.