Being Prepared for Emergencies in the Dental Office: Part 2. Injectable Medications

Dental professionals are responsible for protecting their patients’ well-being. This includes effectively recognizing and managing medical emergencies that may develop in the dental office. Although rare, serious emergencies can and do arise, along with a host of more common medical problems. A key tool in the dental office is having the necessary equipment and medications on hand. The first of this two-part series reviewed the emergency equipment and noninjectable medications recommended for inclusion in a standard dental-practice emergency kit. This part will discuss the injectable medications.

Must-Have Medications for the Emergency Kit

Epinephrine

Epinephrine mediates the fight-or-flight response by its effect on the alpha- and beta-adrenergic receptors; this results in increased blood pressure, faster heart rate, and increased circulation to the skeletal muscle. It also can cause bronchodilation. The indication for its use is a severe allergic reaction (anaphylaxis) or severe bronchospasm (which can occur during an asthmatic event or anaphylaxis).^1,2

Among commercially available epinephrine auto-injectors is the EpiPen®. Its label and packaging describe in detail the steps needed to use it. Another auto-injector, the Auvi-Q®, incorporates synthesized vocal instructions that guide users through every step of the drug-administration process.^1,2

Although administering epinephrine in a life-threatening emergency has no contraindications, the drug should be used cautiously for patients with preexisting cardiovascular disease or arrhythmias or those who take medications such as diuretics, digitalis, and anti-arrhythmics, which may sensitize the heart to the effects of epinephrine. Such patients already have limited cardiovascular capacity. Nonetheless, epinephrine is the drug of choice for a life-threatening allergic reaction.^1,2

Epinephrine is for intramuscular administration only. It should be injected aseptically into the lateral thigh. The dose for adults is 0.3 mg, while the pediatric dose is 0.15 mg. Any patient who receives an accidental injection of epinephrine in the hand or foot should be taken immediately to an emergency room, as intravenous injection poses a risk for ischemia. Also, intravenous administration is not indicated; the high concentration of the drug (1:1,000) can cause a venospasm or cardiac arrhythmia.^1,2

Sometimes patients need more than one dose of epinephrine during a severe anaphylactic reaction, as epinephrine has both a quick onset and offset. Additional doses may be indicated if symptoms such as pruritis, edema, hives, and breathing difficulty persist. For this reason, most emergency kits include additional glass ampoules of epinephrine to be used in case a supplemental injection is required. These come at a concentration of 1:1000 (equivalent to 1 mg/mL). The administration of epinephrine, which has significant hemodynamic effects, underscores the importance of monitoring vital signs throughout the management of a medical emergency.^1,2

As a final note about epinephrine, drawing epinephrine into a syringe and leaving that in the emergency kit is never recommended as a routine measure. Although prefilled syringes are sometimes offered for sale in catalogues, these come in a concentration of 1:10,000—ie, 10 times as diluted as the auto-injectors and ampules. Such doses are intended for advanced cardiac life support in cardiac arrest. Given to help restart the heart, they are injected intravenously and are inappropriate as a response to an allergic reaction. Epinephrine to counter severe anaphylactic reaction is not designed to be left in a syringe in a medical kit for any extended period. Quality-control measures are absent; sterility or efficacy of the syringe’s contents cannot be guaranteed.^1,2

Diphenhydramine

Diphenhydramine is available both as an injected and oral medication. An antihistamine, it blocks H1 receptors and decreases edema and pruritus during allergic reactions. It is indicated either for mild allergic reactions or as an adjunctive treatment for severe allergic reactions. For severe allergic reactions, epinephrine is still considered the first-line drug, followed by an injected antihistamine.^1,3,4

Contraindications include hypersensitivity to the medication or any of its components. Also, patients with narrow-angle glaucoma, ulcers, pyloroduodenal obstructions, bladder and neck obstructions, or symptomatic prostate hypertrophy have a relative contraindication to its use. Diphenhydramine is given at 25 mg to 50 mg orally every 6 to 8 hours. The intravenous or intramuscular dose is 10 mg to 50 mg.^1,3,4

Among potential adverse events that come with the administration of diphenhydramine are thickened bronchial secretions and upset stomach. It also can be sedating, although in children, some degree of excitation may result. Again, intramuscular injection is preferable when treating a severe allergic reaction. With oral consumption, absorption and onset are slower. Furthermore, if the allergic reaction includes any swelling of the airway, it could be obstructed by a pill. Intravenous access can be difficult, particularly if the patient’s blood pressure has plunged. Tissue necrosis has also been associated with intradermal or subcutaneous injections, underscoring the need to deliver the injection into the muscle.^1,3,4

Optional Medications

Corticosteroids

An optional medication for the dental-practice emergency kit is a corticosteroid. Steroids are produced in the adrenal cortex. They bind to receptors and affect changes in DNA transcription. Although their effects are not immediate, taking up to 1 hour for onset, they can affect many metabolic, immune, and inflammatory processes. Because of their anti-inflammatory effects, they are indicated as a secondary medication to prevent recurrent allergic reactions. They can also play a role in the management of an acute adrenal crisis or adrenal insufficiency.^4-7

Although some patients may be hypersensitive to corticosteroids, this class of medications has no other contraindications for administration during a life-threatening reaction. One commonly used corticosteroid is hydrocortisone, which typically is available in a 100-mg vial. It can be given intravenously or intramuscularly. The drug label usually explicitly states whether intramuscular injection is appropriate. Injecting a wrong formulation can result in irritation and tissue necrosis.^5,7

Hydrocortisone is available as an Act-O-Vial preparation, which is a powder form and a liquid diluent, separated by a rubber stopper. To activate a vial, one squeezes the top and bottom of the vial together, enabling the diluent to enter the bottom chamber. The powder becomes liquid, and should be swirled a few times. To dispense the medication, the entire yellow lid need not be removed. On top, a small, perforated portion should be torn off. While wearing gloves, the healthcare professional should wipe the rubber stopper underneath with alcohol before inserting the syringe through the rubber stopper to draw the medication.^5,7

It must be stressed that in response to a severe allergic reaction, epinephrine remains the first-line drug. An antihistamine is the second choice. Because of their delayed effects, glucocorticoids are mainly helpful to prevent the recurrence of allergic symptoms. If the patient can be immediately transferred to an emergency room, he or she will probably receive glucocorticoids there. A dentist who is proficient at securing intravenous access may find it beneficial to have glucocorticoids in the emergency kit.^1-3,5,7

Morphine

Morphine is an opioid receptor agonist. It has many effects; in the context of medical emergencies in the dental office, morphine provides analgesia during an acute myocardial infarction. The contraindication is hypersensitivity to the medication or any of its components. It is administered in a dose from 2 mg to 5 mg intravenously over 5 to 30 minutes. After receiving morphine, the patient should be monitored not only for pain relief but also respiratory depression.^4-6,8

Because morphine is a DEA Schedule 2 controlled substance, it cannot be left in the emergency kit but instead must be kept in a separate drug lock box or drug safe. Morphine causes both central nervous system and respiratory depression, so the provider should have resuscitative equipment such as oxygen, oral airways, a bag-valve mask device, and the reversing agent naloxone (discussed next) on hand. These facilitate maintenance of the airway in the event of respiratory depression. Administering opioids to patients who are already taking opioid antagonists (such as naltrexone) or mixed agonist-antagonists (such as buprenorphine, pentazocine, butorphanol, and nalbuphine) will precipitate a withdrawal reaction. This underscores the importance of obtaining a thorough medical history for all patients.^5,6,8

Naloxone

Naloxone is an opioid receptor antagonist; it reverses opioid-induced respiratory depression. A host of reasons make it a prudent choice for keeping it on hand in the dental office. Patients may have undisclosed access to opioids—hydrocodone with acetaminophen or oxycodone with acetaminophen that they take at home, for example. The patient base may include substance abusers, or the practice may be sedating patients using opioid analgesics, or morphine may be administered as an emergency drug. For these reasons, include naloxone in the emergency kit. The contraindication for naloxone is hypersensitivity to it or any of its components.^4-6,9

Naloxone is available in a 0.4-mg/mL concentration and has two dosing regimens. To reverse oversedation and respiratory depression, between 0.1 mg and 0.2 mg of naloxone should be given intravenously every 2 to 3 minutes until the patient achieves the desired levels of consciousness and respiration. The other regimen is for cases of known or suspected overdose and starts with a higher initial dose of 0.4 mg to 2 mg. This dose should be repeated every 2 to 3 minutes until the patient attains the desired level of consciousness and respiration. However, after administration of approximately 10 mg of naloxone, if the patient is not showing improvement, the symptoms may not be due to an opioid overdose.⁹

Naloxone has a shorter duration of action than an opioid, so once it wears off, the opioid can cause respiratory depression again. If this occurs, naloxone can be re-administered. This highlights the importance of continued monitoring in the settling of opioid-induced oversedation and/or respiratory depression. If recurrent respiratory depression occurs, transfer of care to an advanced setting such as a hospital should be considered.⁹

Careful monitoring of patients who are given naloxone is essential. All opioid effects typically are reversed, including euphoria and sedation, not just respiratory depression. The patient is apt to become extremely alert and may feel some pain because of the reversal of the analgesia. Naloxone also can cause seizures, coma, pulmonary edema, nausea, vomiting, and hemodynamic changes. Intravenously, naloxone typically has an onset of 1 to 2 minutes, while intramuscularly, it can take as long as 2 to 5 minutes. While the naloxone is entering the circulation, it is important to ensure that the patient’s airway is maintained. Naloxone is not a controlled substance, so it can be stored in the emergency kit with the other medications.⁹

Benzodiazepines

Benzodiazepines are agonists for the gamma-aminobutyric acid (GABA) receptor. They have multiple effects, including amnesia, anxiolysis, sedation, and anticonvulsant properties. In the context of medical emergencies in the dental office, they are the drugs of choice for terminating epileptic seizures.^5,6,10-12

For stopping a seizure, the dental team should administer 2 mg to 5 mg of midazolam either intravenously or intramuscularly. Safety for nonintravenous or nonintramuscular routes of benzodiazepines has not been established. Because intravenous access during a seizure may be difficult to establish, intramuscular injection is preferred. Midazolam is water-soluble and an appropriate drug for intramuscular administration. Diazepam is not water-soluble and will burn on injection.^5,6,10-12

Contraindications to benzodiazepine use include any known hypersensitivity to them or their components. Acute narrow-angle glaucoma is also a contraindication. There is a significant risk of respiratory depression resulting from benzodiazepine administration. Patients with respiratory disease or chronic debilitating illness are more susceptible to respiratory depression. Adding a benzodiazepine to the mix is likely to enhance the respiratory depression. Such patients require vigilant monitoring. The provider should have resuscitative equipment, airway equipment, supplemental oxygen, and the ability to maintain the airway. Flumazenil, which is discussed next, is the reversal agent.^4-6,10 Similar to morphine, benzodiazepines are DEA-controlled substances that must be maintained in a drug safe.

Flumazenil

Flumazenil is the reversal agent for benzodiazepine-induced oversedation or respiratory depression. Its mechanism of action is antagonism at the GABA receptor. If midazolam may be administered either as an emergency drug or as part of a sedation regimen, flumazenil should be included in the emergency kit. Furthermore, many patients have access to benzodiazepines at home, including alprazolam, triazolam, and lorazepam, and some might not disclose abuse or misuse of these medications. Some patients may assert that they do not want to be sedated and then take several pills obtained illegally from a friend or family member. This should be kept in mind when considering a differential diagnosis of sedation or respiratory depression.^4-6,13

Flumazenil is available in a 0.1 mg/mL concentration and has two dosing regimens. For oversedation or respiratory depression following benzodiazepine administration, the drug should be supplied at 0.2 mg intravenously, injected slowly over 15 seconds while closely monitoring the patient’s respiration and level of consciousness. At the 1-minute mark, if the patient’s level of consciousness or respiratory status is not acceptable, another 0.2 mg of flumazenil can be administered. In 5 minutes, 1 mg can be administered. Monitor the patient for resedation. Redosing may be initiated in 20 minutes. It is advisable to not exceed 3 mg in 1 hour.

The second dosing regimen is for suspected benzodiazepine overdose in an adult. In such cases, 0.2 mg is injected in the first 30 seconds. If needed, another 0.3 mg is injected over another 30 seconds, and subsequent doses of 0.5 mg over 30 seconds can be repeated after 1-minute intervals, up to a total of 3 mg. Some patients may exhibit a partial response with 3 mg. Rarely, a patient may require up to 5 mg. Again, careful monitoring of the patient for recurrent sedation and respiratory depression is essential. If the patient has not responded within 5 minutes to the maximum of 5 mg, it may not be a benzodiazepine overdose that is causing the loss of consciousness and respiratory depression.¹³

Provided intravenously, the onset of flumazenil can take 1 to 2 minutes, during which the patient’s airway should be carefully maintained. As with naloxone and opioids, the duration of the action of flumazenil (typically 45 to 90 minutes) is shorter than that of benzodiazepine. Thus, sedation and respiratory depression may recur. The patient may need to be monitored longer than 90 minutes to ensure that the original benzodiazepine has definitively worn off.¹³

If intravenous access cannot be secured, flumazenil can be injected intramuscularly, as it is nonirritating. Findings from studies indicate that sublingual administration is ineffective and may actually worsen any impending or actual airway obstruction because of the tongue being pushed further back. Most patients respond well to 6 mL to 10 mL (0.6 mg to 1 mg). This volume can be split into two syringes and injected into each deltoid.^14,15

Contraindications to flumazenil include a hypersensitivity to it. Also, if a patient is taking benzodiazepine for a seizure disorder, flumazenil administration may precipitate another seizure. In patients exhibiting signs of a cyclic antidepressant overdose, flumazenil can actually worsen the seizures and cardiac arrhythmias if a cyclic antidepressant overdose is suspected. Flumazenil is not a controlled substance, and, therefore, can be kept in the emergency kit.¹³

Rescue Training

Although this article has not explored the intricacies of cardiopulmonary resuscitation, automated external defibrillator use, or rescue breathing, based on relevant state licensing requirements various members of the dental practice staff may need to have current basic life support or cardiopulmonary resuscitation certification. If the dental practice is providing sedation, having training in advanced cardiac life support will be necessary, including possessing a host of other advanced cardiac life-support medications that are required for the emergencies associated with sedation procedures.

Conclusion

Preparation for the myriad issues that may appear in the dental practice is not only prudent but imperative for the well-being of patients. Understanding what medications are necessary to keep on hand and how and when to use them is important for the entire dental team. 

About The Author

Dr. Saraghi is an attending anesthesiologist at St. Barnabas Hospital, Bronx, New York. She is a member of the American Society of Dental Anesthesiologists and the American Dental Society of Anesthesiology. She maintains a private practice in New York City.

Disclosure

Dr. Saraghi has received an honorarium for writing this article.

References

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