The word bruh is slang. It can mean really or sometimes bro. Their  is the possessive pronoun of them or themselves.   They're is a contraction or shortening of 'they are'.   . Their means belonging to people or things previously mentioned or  easily identified (Your parents do not look similar, except for  their noses).
Claritin is an antihistamine. It blocks histamine, a chemical that causes congestion, itching, and other allergic reactions. Antihistamines can also make you sleepy, but Loratadine is a low-drowsiness version. Claritin D is a combination medicine for allergies. Loratadine (an antihistamine) prevents allergy symptoms like runny nose, sneezing, and itchy eyes or skin.
Loratadine, sold under the brand names Claritin and Claritin-D (which contains loratadine plus pseudoephedrine), is an over-the-counter antihistamine medication. The drug is often used to treat nasal allergies (allergic rhinitis) and hives (urticaria). Antihistamines work by blocking the release of histamine, a chemical your body naturally produces when it is exposed to something that causes an allergic reaction. Loratadine was originally approved by the Food and Drug Administration (FDA) in 1993 and was originally manufactured by Bayer Healthcare.