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.
Claritin, a brand name of loratadine, is an over-the-counter (OTC) medication used for the relief of symptoms of seasonal allergies. It is also used to treat chronic itching of unknown cause. This drug is classified as an antihistamine. Claritin works by blocking the binding of histamine in the body; histamine is the chemical that enters the body and produces the symptoms of allergies. The medication can produce many common, non-serious side effects.