The cardiac glycoside digoxin is taken by an increasing number of dental patients. The drugs used in dental treatment which may interact with digoxin include tetracyclines, erythromycin, catecholamines in local anaesthetic preparations (which may increase the risk of arrhythmia) and non-steroidal anti-inflammatory drugs such as diclofenac.

It is prudent to use an alternative to adrenaline or other catecholamine vasoconstrictors in local anaesthetics. Alternative vasoconstrictors available in dental preparations include felypressin with prilocaine hydrochloride. Notwithstanding this comment, clinically there appears to be no reaction to up to 4 mL of local anaesthetics containing adrenaline in the low concentration of 1:200 000 (5 microgram/mL). Extra care should be taken to avoid intravascular injection.

Treatments should be carefully planned. Consultation with the patient's medical practitioner may be necessary. Appointments for patients taking digoxin should be kept as brief as practicable. If extensive treatment is planned it is often prudent to monitor the patient with an electrocardiograph and oximetry. Sometimes oxygen may be needed, so it should be available in the surgery.

R.G. Woods

Australian Dental Association