ISHIK UNIVERSITY FACULTY OF DENTISTRY Oral Pharmacology 2016-2017

Drug Effects on Salivary Glands and Saliva Saliva is produced in and secreted from salivary glands. The basic secretory units of salivary glands are clusters of cells called an acini. These cells secrete a fluid that contains water, electrolytes, mucus and enzymes, all of which flow out of the acinus into collecting ducts.

Drug Effects on Salivary Glands and Saliva Saliva consists of two components that are secreted by independent mechanisms. First a fluid component which includes ions, produced mainly by parasympathetic stimulation secondly a protein component released mainly in response to sympathetic stimulation Salivary gland secretion is mainly under autonomic nervous control, although various hormones may also modulate salivary composition. Secretion appears to be dependent on several modulatory influences which act via either a cyclic AMP or calcium dependent pathway.

Parasympathetic stimulation produces copious saliva of low protein concentration while sympathetic stimulation produces little saliva but of high protein concentration and may thus give a sensation of dryness.

Functions of Saliva Lubrication and binding: the mucus in saliva is extremely effective in binding masticated food into a slippery bolus that (usually) slides easily through the esophagus without inflicting damage to the mucosa. Saliva also coats the oral cavity and esophagus, and food basically never directly touches the epithelial cells of those tissues.

Functions of Saliva Solubilises dry food Oral hygiene: The oral cavity is almost constantly flushed with saliva, which floats away food debris and keeps the mouth relatively clean. Flow of saliva diminishes considerably during sleep, allow populations of bacteria to build up in the mouth -- the result is dragon breath in the morning. Saliva also contains lysozyme, an enzyme that lyses many bacteria and prevents overgrowth of oral microbial populations.

Functions of Saliva Initiates starch digestion Provides alkaline buffering and fluid Evaporative cooling

Salivary Gland Disorders Certain diseases and disorders, as well as certain drugs, can cause the salivary glands to malfunction and thus decrease saliva production. Diseases include Parkinson's disease, human immunodeficiency virus (HIV) infection, Sjögren's syndrome, depression, and chronic pain. Drugs that decrease saliva production include certain antidepressants, antihistamines, antipsychotics, sedatives, methyldopa, and diuretics.

The salivary glands often malfunction after a person has had chemotherapy or head and neck radiation for the treatment of cancer. Dry mouth due to radiation is usually permanent, especially if the radiation dose is high; that due to chemotherapy is usually temporary.

However, not all cases of dry mouth are caused by salivary gland malfunction. Drinking too little liquid and breathing through the mouth can dry the mouth. Anxiety or stress can also result in a dry mouth. The mouth may also dry somewhat as a person ages, although this is probably due to the greater likelihood of taking a drug that causes dry mouth than to the aging process itself.

an inadequate amount of saliva leads to more cavities, especially in the roots of teeth. Dry mouth, if its severe, can also lead to difficulty speaking and swallowing. Salivary Gland Swelling: Salivary gland swelling can occur when one of the ducts that carry saliva from the salivary gland to the mouth is blocked. Pain may occur, especially during eating.

Dry Mouth Dry mouth has a variety of possible causes. Common habits such as tobacco smoking, alcohol use (including in mouthwashes) and use of beverages containing caffeine (coffee, some soft drinks) can cause some oral dryness. A wide range of drugs can give rise to oral dryness. Dry mouth is a common complaint in the elderly mainly as consequence of the large number of drugs used

Causes of dry mouth Iatrogenic Drugs Irradiation Graft vs host disease Salivary gland disease Salivary aplasia (agenesis) Sjogren’s syndrome Sarcoidosis Cystic fibrosis Primary biliary cirrhosis Infections HIV Hepatitis C Human T lymphotropic virus 1 (HTLV-1) Dehydration Psychogenic

Drugs associated with dry mouth Tricyclics antidepressants Muscarinic receptor antagonists for treatment of overactive bladder Alpha receptor antagonists for treatment of urinary retention Antipsychotics such as phenothiazines Diuretics(Amiloride) Antihistamines (cetirizine)

Drugs associated with dry mouth Antihypertensive agents (Amlodipine, captopril,…) Antidepressants (serotonin agonists, or noradrenaline and/or serotonin re-uptake blockers) Appetite suppressants Decongestants and cold cures Bronchodilators (Ipratropium) Antidiarrhoeal drugs (Loperamide) PPI (omeprazole, Lansoprazole)

Drugs associated with dry mouth Skeletal muscle relaxants (baclofen) Antimigraine agents Benzodiazepines, hypnotics, opioids and drugs of abuse H2-antagonists and proton pump inhibitors Retinoids Anti-HIV drugs such as dideoxyinosine (DDI) and protease inhibitors

Treatments Change medication that cause dry mouth Recommend products that moisturize mouth: artificial saliva or moisturizers to lubricate mouth Prescribe medication that stimulates saliva (pilocarpine(salagen), Cevimeline(Evoxac)) Protect teeth: To prevent cavities: fluoride trays by dentist, using chlorhexidine mouth wash to control cavities.