Don’t forget the contribution of medicines to oral health

Florence is a delightful 72-year-old lady new to your practice. She recently moved to the district following the death of her husband, Jim, who is buried here. She and Jim were married 53 years before he passed.

She visits today because of pain in tooth 16. The pain is sensitive to heat and cold. It can be both sharp and dull. All the teeth are her own, and none are missing. There is no tenderness and no swelling or redness of gums. Florence is apyrexial, there is nil lymphadenopathy, and there is no worsening of pain as the head is tilted.

She has had no dental work recently, stating she likely should have tried to visit the dentist, but the closest one is 30km away. Florence does not drive, explaining she “never had the need”. Furthermore, she is very concerned at the projected cost.

Apart from her “silly foot”, which has been a bother to her over the previous two years (she was significantly burnt by an urn of hot water tipping into her gumboot), she has “no real complaints”. Her current long-term medicines and indications are shown in the table.

She saw a pain specialist for her foot six months ago in the city she formerly lived in. The specialist started gabapentin, which has built up to a dose of 900mg daily, and added in nortriptyline. This has given her the most relief to date. She states she has been able to walk further distances and sleep for longer periods.

Investigations reveal the following:

• sodium – 140mmol/L
• potassium – 3.8mmol/L
• urea – 6.3mmol/L
• creatinine – 68μmol/L
• estimated glomerular filtration rate – 75ml/min
• glucose – 6.5mmol/L
• HbA1c – 35mmol/mol
• blood pressure – 152/90mmHg, repeated after 10 minutes with little change
• heart rate – 65 beats per minute, regular with dual heart sounds
• BMI – 23kg/m².

For Māori, appearing in more than one group compounds the disadvantage

There is a well-established link between oral health and systemic health. Therefore, optimising oral healthcare should be a concern of all those involved in healthcare delivery. Sometimes, dental problems may not be obvious to health professionals, especially in older people.¹

The case for access to funded dental services in New Zealand has been promoted for many years.² It is another area where health inequity pervades for Māori.³ The impact of inaccessibility can extend across groups with disability, lower socioeconomic status, mental health conditions and geographic isolation. For Māori, appearing in more than one group compounds the disadvantage.

Until a national solution is delivered, it is important that health professionals who aren’t dental specialists regularly consider the place of oral care in overall health delivery.

Medicines can affect oral health in a variety of ways (see panel). Hyposalivation is one identified mechanism, with saliva having antimicrobial activity that helps to prevent tooth decay and tooth wear. Saliva is also essential to digestion, swallowing and speech.

Many drugs are reported to cause salivary gland hypofunction, leading to xerostomia. Muscarinic acetylcholine receptors (M1, M3) and alpha-1 and beta-1 adrenergic receptors on saliva secretory cells mediate salivary secretion. Medicines that inhibit these receptors can decrease saliva flow.

Florence confirms her mouth has felt dry for some months and may have gotten worse over the last month. Her approach to deal with this has been to suck on boiled, sugary sweets. Her children have commented that she seems to never be without a lolly.

Considering the anticholinergic burden of medicines is a reasonable place to start.

The ACB Calculator (acbcalc.com) can help indicate the risk of anticholinergic impact when making prescribing decisions – nortriptyline is given an anticholinergic burden rating that is “high risk”. This risk extends to more than oral health.

Other medicines with an ACB high-risk rating include antipsychotics (eg, clozapine and olanzapine) and medicines for urinary frequency and incontinence (eg, oxybutynin and solifenacin).

The list of medicines causing salivary gland hypofunction and xerostomia is, however, significantly wider than those inhibiting parasympathetic activity (tinyurl.com/MedsSaliva).⁴

Clonidine (a centrally acting anti-adrenergic agent) and gabapentin (for which a high level of evidence also exists to cause xerostomia) were implicated when Florence first noticed symptoms. Considering alternate medicines to those with high risk should be factored in if possible.

The other medicines in Florence’s regimen to bear in mind are tiotropium⁵ (a long-acting muscarinic antagonist) and perindopril. ACE inhibitors can directly cause dry mouth and lichenoid sensitivity reactions.⁶

A further consideration for Florence with respect to oral healthcare is the budesonide, which can cause pharyngitis, oral mucositis and candidiasis, particularly in older people.

Florence feels she has benefited from the nortriptyline, while the clonidine patch tried earlier made her feel “awful”. She is due to see the pain specialist again in a month for review but is reluctant to change her current pain regimen. After the specialist appointment, it is agreed that she will check in to consider whether the gabapentin can be down titrated.

Florence must not continue consuming sugar when addressing the dry mouth. Chewing sugar-free gum can be a better option, and staying hydrated with water.

Discussing dental care can be helpful. Texting links to Health Navigator (eg, tinyurl.com/HNavOralHealth) or printing out resources during the consult is often appreciated, depending on preference.

Florence states she is particular about regularly brushing her teeth twice a day with fluoride toothpaste and flossing. However, she does not recall being advised to rinse and gargle with water after using her inhalers, which is emphasised to her now.

Although ACE inhibitors can affect oral health, nortriptyline (and before it, clonidine) alongside the gabapentin are more likely to have impacted Florence.

Other antihypertensives can also be problematic. Calcium channel blockers can cause gingival enlargement, while diuretics are also implicated in hyposalivation. Beta-blockers, although not efficient as antihypertensives, are not considered an option for Florence, given previous episodes of bradycardia and hesitation with use in asthma-chronic obstructive pulmonary disease overlap syndrome. For these reasons, the perindopril dose is doubled to 4mg at follow-up in two weeks, when blood pressure and creatinine and electrolyte levels are reviewed.

A task is set to check Florence’s old notes for a spirometry result. Ascertaining an appropriate inhaler regimen is required, including the continued need for tiotropium.

On balance, it is considered likely that Florence has acute pulpitis, and advising her to see a dental practitioner remains the central advice. On this occasion, the transport issue is solved by the local Māori health provider.

The dentist enables a scheme for Florence to pay on a weekly schedule. However, it remains that primary care practitioners are required to be creative in addressing dental issues. Considering the implications of medicines can be an important step to help your patients.

Details have been changed to protect patient confidentiality

Leanne Te Karu is a pharmacist prescriber at Pihanga Health in Tūrangi; Linda Bryant is a pharmacist prescriber at Newtown Union Health Service and Porirua Union and Community Health Service, Wellington