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ISHIK UNIVERSITYFACULTY 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
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.