Sublingual fentanyl solves quickly and is absorbed through the sublingual mucosa to provide rapid analgesia. Nitroglycerin is available in sublingual tablets, sprays, ointments, and patches. Other routes of administration include sublingual, intramuscular and transdermal. In comparison with sublingual tissue, buccal tissue is less permeable resulting in slower absorption. Lymph from the sublingual salivary gland drains into the submandibular lymph nodes. Common routes of administration include sublingual, buccal, and intranasal. One study found no difference between oral and sublingual estradiol in suppression of LH levels. Other NRT options are available, including nicotine mouth sprays and sublingual tablets. Administration of flumazenil by sublingual lozenge and topical cream has also been tested. It receives the secretions from the submandibular and sublingual salivary glands. Sialadenitis is swelling and inflammation of the parotid, submandibular, or sublingual major salivary glands. The major salivary glands consist of the parotid, submandibular, and sublingual glands. They empty the submandibular (submaxillary) and sublingual salivary glands. Buccal and sublingual administration of estradiol have similar characteristics. Anaphylaxis during sublingual immunotherapy treatment has occurred on rare occasions.