CONTRAINDICATIONS TO THE USE OF VASOCONSTRICTORS IN DENTISTRY

*It is essential that you know this list!

1. Absolute Contraindications:

   1. Heart Disease

      1. unstable angina

      2. recent m.i. (within 6 mos., get a med consult)

      3. recent coronary artery bypass surgery

      4. refractory arrhythmias

      5. untreated/ uncontrolled severe HTN

      6. untreated/ uncontrolled congestive heart failure

   2. Uncontrolled hyperthyroidism: thyroid hormones cause an increased beta-receptor response, will get high cardiovascular load and can lead to heart failure

   3. Uncontrolled Diabetes: epinephrine antagonizes insulin

   4. Sulfite sensitivity: metabolism of vasoconstrictors yields sodium metasulfite.

   5. Steroid-dependent asthma: because of sensitivity to sulfites

   6. Pheochromocytoma: lots of epi from tumor growth, don’t want to add more.

2. Relative Contraindications:

   1. Pts taking the following drugs: (** #’s 1-3 have effects on the heart)

      1. Tricyclic antidepressants: block amine pump; increase BP, HR and sympathetic tone

      2. Phenothiazine antipsychotics: block alpha receptors so you don’t get beta response (dec. BP)

      3. MAO inhibitors: MAO breaks down catecholamines, when MAO is inhibited the vasoconstrictors cant get broken down as well.

      4. Nonselective beta-blockers (ie. propranolol): you’d get alpha response, severe HTN and reflex bradycardia

      5. L-dopa (for Parkinson’s disease): L-dopa is metabolized to dopamine, acts on heart beta-receptors

   2. Cocaine abusers: cocaine blocks the amine pump, causing increased adrenergic responses.

3. Precautions:

   1. Recent Stroke: if within 6 mos., get a med consult before giving vasoconstrictor

In general, vasoconstrictors reduce the toxic risk of a local anesthetic, as previously discussed. However, if the LA is accidentally injected into a blood vessel, epinephrine can actually increase the toxic risk. Cardiac stimulation induced by epinephrine accelerates the spread of LA to the CNS. This may increase the LA toxicity as much as twofold!!!

Category: Pharmacology Notes