Medications are used commonly these days. These may vary from simple medicines for headache, upset stomach or more severe ones such as those for diabetes or epilepsy. Most but not all drugs have effect on the health of oral tissues. These have acquired greater attention recently due to the increasing number of cancer chemotherapy which affects the oral tissues greatly. Today the medical and dental professionals have both realised and accepted this fact. So both the general medicine and the dentist should work together to provide the patient with the best treatment with minimal side effects. One of the most common and the earliest known adverse/side effect involved the use of tetracycline. The administration of tetracycline to pregnant women resulted in tooth staining/discoloration in their children. It resulted in yellow brown stains on the teeth of these children. Since then many drugs have been discovered and studied which caused side effects on teeth and other oral tissues.
People use medications regularly for the treatment, maintenance or relief of certain conditions such as those for treatment of allergic reactions, infections or relief of pain. It is important to inform your dentist about the medication you are taking as this will help the dentist better understand an oral lesion/abnormality which might be due to the drug you are undertaking. Also it provides a better insight to the treatment of the concerned problem.
The dentist will also inform you the patient about the potential side effects of the medication and ways to prevent it or reduce the intensity of the adverse effects.
The oral tissues are the major site of occurrence of side effects of most drugs with subtle changes in the skin. This is because of absence of keratinized epithelium of skin in the oral mucous membrane and the presence of high turnover of the cells of the oral mucous membrane.
Also the oral tissues especially the teeth take a longer time to mature than most other tissues thus providing longer time for the drugs to act and affecting in similar manner.
Most common oral effects of medications include dry mouth, a common condition that may lead to decay of teeth, opportunistic infections like candidiasis and/or difficulty in speaking and swallowing. Various other common side effects of medications on oral tissues are explained below:
Oral mucous membrane may be involved alone or the hypersensitivity reaction may be a part of the generalized skin reaction. The common type of hypersensitivity reaction that involves the oral tissues is a delayed reaction mediated by sensitized T lymphocyte. Fixed drug reactions, stomatitis medicamentosa occurs with systemic usage of drugs and contact hypersensitivity is seen in stomatitis venenata. These usually result in erythematous lesions in mild cases and ulcers in severe ones. The lesions usually appear within 24 hours of drug intake. Lesions usually resolve with the discontinuation of the offending drug.
Common drugs which have been associated with fixed drug reactions are: Barbiturates, Chlorhexidene, Indomethacin, Lidocaine, Penicillamine, Sulphonamides, etc.
It is a localized reaction of the oral mucosa usually after repeated contact with the causative agent. It may result in erythema or ulcerative lesions with or without burning sensation. The reaction may occur as early as one day after the drug usage or may occur years post exposure.
Antibiotics, chewing gums, iodine, mouthwashes, toothpastes, certain cosmetics, etc have the potential to cause contact somatitis.
Another common reaction mediated by the immune system is the aphthous ulcers or more commonly known as the canker sores. These are tiny, painful lesions which occur either singly or in groups on the labial or buccal mucosa. These usually heal without scar formation within 10 – 14 days. Various drugs including NSAIDs, captopril, losarton and penicillamine can cause aphthous ulcers.
Certain drugs such as sedatives, anticholinergics, omeprazole, anti cancer drugs, antidepressants etc cause dry mouth as these affect the function of the saliva glands reducing the saliva. Some of the common problems associated with it are burning sensation, constant sore throat, speech problems, difficulty in swallowing and hoarseness.
Tooth discoloration may be intrinsic or extrinsic. Intrinsic stains are usually caused by drugs which are taken during and affect the tooth development, more so during the stages of enamel and dentin formation. Such drugs, for example, tetracycline gets accumulated in the dentin and enamel of the developing tooth and appears as yellow or brown stains on the tooth. Extrinsic stains are the ones which are taken up by the tooth after development. These include tea and coffee stains and stains caused by some drugs such as chlorhexidine, tobacco, copper salts, etc.
Pigmentation may occur either due to systemic absorption or local use of drugs in the oral cavity. Pigmentation has been reported in cases taking mercury, arsenic, gold, copper, zinc etc, especially around the gingival margins around the teeth. These are more prominent in the presence of plaque and inflammation. These may be temporary or permanent but usually most of the pigmentation disappears with the discontinuation of the drug.
Black Hairy Tongue
In the case of black hairy tongue there is elongation of the filliform papillae of the tongue resulting in the formation of long hair like overgrowth which gets stained black or brown over the time due to coffee, tea, and food products and also due to proliferation of chromogenic micro-organisms. Excessive smoking, oral antibiotics and poor dental hygiene can cause black hairy tongue.
Burning Mouth Syndrome
This syndrome may occur due to hormonal with drawl, iron or vitamin deficiencies, psychogenic factors or hypersensitivity reactions to various dental materials or drugs.
Glossitis or inflammation of the tongue is characterized by intense pain and swelling that may be referred to the ear. It usually results in difficulty in speaking, swallowing along with systemic signs such fever and enlarged lymph nodes. Glossitis though not a common side effect is usually associated with penicillin, bleomycin, lansoprazole, etc.
More commonly referred to as burns of the oral mucosa. Aspirin, cocaine, hydrogen peroxide, phenytoin, penicillin, etc can cause either local irritation or ulceration in the oral cavity.
Vesico bullous lesions appear to occur as a direct consequence of local irritants. Patients usually taking swallow able drugs or inhalers are more prone to it.
Drug induced lichenoid reactions are characterized by white lace pattern on the buccal mucosa. It can be differentiated from true lichen planus by the rare occurrence on the buccal mucosa and also the disappearance of the lesions after the discontinuation of the offending drug. The drugs with potential to cause lichen planus are mercury, lithium, tetracycline, chloroquin, streptomycin and many others.
Drug Induced Gingival Hyperplasia
It is the painless overgrowth of the gingival tissues, usually the interdentally papilla is more affected, later extending to other areas of the gingival. The gingival enlargement is usually more severe in the mandibular and maxillary anterior regions. The presence of local factors such as plaque, calculus etc aggravates the conditions. The common drugs causing the drug induced gingival enlargement are cyclosporine, phenytoin, calcium channel blockers like nidefine and oral contraceptives.
Reducing the dose of the offending drug along with the maintenance of good oral hygiene usually suffices the treatment for gingival hyperplasia. In severe cases complete stoppage and/or changing to an alternative drug is required to treat the case.
Effect on Salivary Glandds
The salivary glands are under the direct control of the nervous system, specially the parasympathetic system. So all the drugs affecting the parasympathetic system affect the function of the salivary glands.
Reduction in salivary gland function i.e. reduced salivary flow is known as xerostomia. It leads to dental decay and also alteration in other soft tissues of the mouth. The drugs causing xerostomia not only caused reduction in the salivary flow but also decrease in salivary calcium and phosphate concentration which alters the buffering capacity of the saliva. Drugs that cause xerostomia most commonly are benzodiazepines, morphine, calcium channel blockers, etc
Some drugs alter the function of salivary glands by increasing the rate of formation of saliva, commonly known as ptyalism. The saliva is thin and watery without its usual buffering properties leading to decay of hard and soft tissues of the oral cavity.
Drugs that affect the functioning of the salivary glands also affect the taste perception as saliva plays an important role in taste perception. Also this may cause alteration in taste by reducing the sensitivity in taste perception, or a total loss of taste or a disturbance in correct identification of taste. Drugs that are capable of affecting/altering the taste sensation are aspirin, cetrizine, various antibiotics like penicillamine, ofloxacin, metronidazole, etc.
Halitosis or bad breadth can result from poor oral hygiene, ingestion of certain drugs, use of tobacco products, oral or dental infections, and some systemic disorders. Sublingual nitrate and disulfiram have the potential to cause halitosis.
It is the condition of lips characterised by inflammation and cracking of corners of the lips. This is usually associated with fungal infections or may be due to drugs causing xerostomia.
At times the systemic drug therapy alters the oral micro flora predisposing the mouth to various bacterial and fungal infections. Also the drugs that reduce/suppress the immunity of the individual make the individual susceptible to opportunistic infections such as candidiasis. Such drugs include corticosteroids, antimicrobials, immunosuppressive agents, anticancer drugs, etc.
Drugs affecting the activity of liver affect the coagulability of blood and wound healing thus are predisposing the individual to dry socket (alveolar ostetitis) following extraction. The uses of oral contraceptives have also been associated with significant increase in the frequency of dry socket especially after surgical extractions or impaction.
A drug induced hypersensitivity reaction, facial oedema occurs as a consequence of alteration in bradykinin metabolism in the susceptible patients. The angiotensin converting enzyme inhibitors such as captopril, enalapril are the most important cause. Discontinuation of the drug helps reduce or treat the oedema.
Taking care of your oral health during drug use
Here are some easy ways to prevent or reduce the adverse effects of various drug therapies. Maintaining a good oral hygiene affects the general overall health and helps you feel better. The following may help in maintaining good oral hygiene and reducing the side effects of drugs:
Always be on the lookout for abnormal oral lesions when you are on long term drug regimen. If you notice any of the above signs and symptoms, immediately bring them to the notice of the concerned doctor and the dentist. Reduction in dosage of the drug or changing to an alternative drug may help. Sometimes active treatment of the concerned effect may also be required. Getting professional consultation as soon as possible helps and is the best strategy.
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