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Treatment of specific phobias of clinical procedures in adults

Treatment of specific phobias of clinical procedures in adults
Author:
Yujuan Choy, MD
Section Editor:
Murray B Stein, MD, MPH
Deputy Editor:
Michael Friedman, MD
Literature review current through: Dec 2022. | This topic last updated: Aug 27, 2021.

INTRODUCTION — Acute procedural anxiety is an excessive fear of medical, dental, or surgical procedures resulting in acute distress or interference with completing necessary procedures.

Specific phobias, a subset of presentations of acute procedural anxiety, are diagnosed only when the patient’s fears are specific to the procedure and its immediate effects (rather than, for example, fear of a potentially serious diagnosis or of discomfort during the procedure) [1]. The most prominent specific phobias of clinical procedures and typically associated fears are:

Dental phobia – Experiencing pain during dental treatment

Blood injection-injury phobia – Seeing blood during venipuncture

Magnetic resonance imaging claustrophobia – Suffocating during a magnetic resonance imaging scan

This topic reviews our approach to treating specific phobias of clinical procedures in adults. Treatment of acute procedural anxiety other than specific phobias is discussed separately. The epidemiology, clinical manifestations, course, screening, assessment, and differential diagnosis of acute procedural anxiety are also discussed separately. The epidemiology, clinical manifestations, course, diagnosis, and treatment of other specific phobias are also discussed separately. (See "Treatment of acute procedural anxiety in adults" and "Acute procedure anxiety in adults: Epidemiology, clinical manifestations, and course" and "Acute procedure anxiety in adults: Course, screening, assessment, and differential diagnosis" and "Specific phobia in adults: Epidemiology, clinical manifestations, course and diagnosis" and "Cognitive-behavioral therapies for specific phobia in adults" and "Pharmacotherapy for specific phobia in adults".)

GENERAL PRINCIPLES — Several general principles can be useful in the management of specific phobias of clinical procedures. Unless otherwise specified, these guidelines are based on our clinical experience.

Establish a trusting clinician-patient relationship – A trusted clinician may be better able to explain to the patient why an indicated procedure is necessary and to reassure them of its safety.

Educate the patient about their condition, reasons the procedure is recommended, and what they can expect, eg, about the expected amount of pain. This information should be provided face-to-face with sufficient time to allow the patient to ask and receive answers to their questions [2].

Educate the patient about the procedure – Address any preconceived notions about the procedure and potential outcomes, and allow the patient to ask questions and bring up concerns [3-5].

Determine what aspect of the procedure is most anxiety provoking for the patient.

Directly address that underlying focus of fear with the patient through acknowledgment and education.

Acknowledge the patient’s anxiety [5] and normalize the experience of anxiety if it is common. Avoid telling patients not to worry as this may undermine their concerns and imply that they are able to stop their worries at will.

Provide the patient with as much control as possible during the procedure – This may include assuring the patient that nothing will happen during the procedure that is not agreed upon in advance. Allow the patient to interrupt or end the procedure if anxiety becomes intolerable, as long as it is safe to do so [4,5].

Make the patient as comfortable as possible during the procedure. As an example, allow family members or friends to be present during the procedure if desired by the patient and not clinically contraindicated [4].

DENTAL PHOBIA — Dental phobia, the fear and frequent avoidance of going to the dentist, can be treated with psychotherapeutic interventions or with medication-induced sedation. Despite the availability of treatments with evidence of efficacy, more acceptable and tolerable treatments are needed, including interventions to enhance patient motivation to seek and stay in treatment. Drop-out rates in clinical trials of psychotherapies and medications in dental phobia are among the highest among subtypes of specific phobia [6], ranging from 44 to 59 percent [7-10]. (See "Acute procedure anxiety in adults: Epidemiology, clinical manifestations, and course", section on 'Dental phobia'.)

Approach to treatment — For most cases of dental phobia, we suggest in vivo exposure as first-line treatment rather than other interventions. There are no clinical trials comparing exposure therapy with other psychotherapies in dental phobia. Based on our clinical experience and comparisons of placebo-controlled trials across these interventions, exposure therapy appears to be the most effective psychosocial treatment. (See 'Psychotherapies' below.)

There is no evidence of differential efficacy between psychotherapy and sedating medication in dental phobia, but impairing side effects of some medications, eg, benzodiazepines, can last hours after the procedure. Dental care is a recurring need, and limited evidence suggests that psychotherapy may have longer-lasting effects compared with medication [10,11]. As an example, a trial of pretreatment prior to oral surgery randomly assigned 91 patients with dental anxiety to receive either psychotherapy consisting of information, cognitive restructuring, relaxation, and applied relaxation, to midazolam or to no pretreatment [10]. Patients receiving either psychotherapy or midazolam experienced reduced anxiety prior to surgery compared with the control group. At follow-up two months after surgery, patients treated with psychotherapy were more likely to have received continued dental treatment compared with patients treated with midazolam (70 versus 20 percent). On assessment one year after the surgery, only the group that received psychotherapy maintained benefit from treatment. (See 'Psychotherapies' below and 'Medication' below.)

In vivo exposure can be provided as an independent modality or within the context of a broader cognitive behavioral therapy. Although there is a lack of supporting evidence from clinical trials, in our clinical experience, it may be useful to augment exposure therapy with cognitive restructuring or relaxation training. (See 'In vivo exposure therapy' below and 'Cognitive-behavioral therapy' below.)

Some patients prefer medication to psychotherapy. For these patients and those with the indications below, in the absence of strong evidence of differential efficacy, first-line treatment with nitrous oxide is a reasonable alternative to exposure therapy:

Lack access to exposure therapy

Need dental treatment on an emergent basis

Experience anxiety that is too severe to tolerate exposure therapy

Failed previous, adequate trial of exposure therapy

Other medications for dental phobia have disadvantages compared with nitrous oxide. The sedating effects of benzodiazepines can last for hours compared with minutes for nitrous oxide (table 1) and can be accompanied by psychomotor impairment. General anesthesia with deep sedation requires intensive monitoring of cardiovascular and respiratory functions and other vital physiological parameters by a trained clinician. It should be reserved as a last resort when other forms of sedation are not an option or not effective [12]. Indications favoring general anesthesia include:

Severe anxiety that is not controlled by other forms of sedation methods

Inability to tolerate other forms of sedation

Patients are not able to cooperate or communicate

Need for dental surgery or treatment requiring multiple sessions with other sedation

Psychotherapies — Small clinical trials support the efficacy of cognitive and behavioral therapies in the treatment of dental phobia. In the absence of comparative trials, our clinical experience favors in vivo exposure (a behavioral therapy), with or without a cognitive component, to treat dental phobia. Trials of psychotherapy for dental phobia are limited by variations in the definition of dental phobia and in other inclusion criteria, assessment methods, and treatment components. These therapies are reviewed below:

Cognitive-behavioral therapy — Cognitive-behavioral therapy (CBT) is a form of psychotherapy that incorporates psychoeducation, cognitive restructuring, and behavioral intervention to reduce symptoms of anxiety. Behavioral interventions may include various forms of exposure therapy or relaxation training. (See 'Cognitive restructuring' below and 'In vivo exposure therapy' below.)

A trial suggested that brief CBT may be an efficacious treatment for dental phobia. The trial randomly assigned 104 patients with dental phobia to two to four sessions of CBT or to a wait-list control [13]. The brief CBT was administered by a dentist and included in vivo exposure to the patient’s most feared aspect of dental treatment. Only 60 percent of the patients completed the trial. Patients receiving CBT reported decreased dental fear compared with those in the control group; the effects were maintained at two years. An intent to treat analysis was not reported.

Brief CBT delivered via a computer application may also have benefits for patients with dental phobia. A trial randomly assigned 151 patients with the disorder to a one-hour computer-based CBT intervention immediately prior to their dental appointment or to a control group that received no treatment prior to the appointment [14]. Patients who received CBT reported decreased dental anxiety and avoidance at the one-month follow-up. Among patients who initially met DSM-IV criteria for dental phobia at enrollment, those who received CBT were less likely to meet diagnostic criteria for dental phobia at one-month follow-up compared with those assigned to the control condition (51.4 versus 74.4 percent).

Eye movement desensitization and reprocessing — Eye movement desensitization and reprocessing (EMDR) is a form of CBT treatment that incorporates saccadic eye movements during exposure [15]. EMDR has been found to reduce symptoms of posttraumatic stress disorder in several randomized trials, though some researchers have suggested that exposure is the active component of EMDR, and eye movements may not be needed [16].

EMDR may be efficacious in the treatment of dental anxiety. A trial randomly assigned 31 patients with dental phobia and a history of prior traumatic dental treatment to EMDR or a waitlist control [17]. After three months, patients receiving EMDR experienced reduced dental anxiety and avoidance behavior compared with the waitlisted group, an effect that was maintained at 12 months.

In vivo exposure therapy — Exposure-based strategies involve repeated, systematic confrontation of the feared stimulus to facilitate fear reduction through extinction learning [18]. Patients are exposed to feared situations from least to most feared and avoided. In vivo exposure involves experiencing the stimulus in real world situations in a safe and controlled manner. (See "Cognitive-behavioral therapies for specific phobia in adults", section on 'Exposure therapy'.)

Exposure therapy can be delivered as an isolated intervention or as part of a multi-modal CBT. (See 'Cognitive-behavioral therapy' above.)

A single randomized trial of 40 patients with dental phobia found that treatment with in vivo exposure therapy resulted in decreased anxiety, increased positive thinking and decreased negative thinking about dental treatment, and decreased avoidance of dental treatment compared with a waitlist control [19]. Mean absence of dental care before treatment was 11.4 years. In the year following treatment with exposure therapy, a total of 77 percent of patients sought dental care. Individuals assigned to receive five sessions of exposure therapy experienced greater reduction of dental anxiety compared with patients treated with a single session, but avoidance behavior post-treatment did not differ between the two groups.

Cognitive restructuring — Cognitive restructuring involves the identification and modification of overly negative cognitions regarding the feared stimulus. Cognitive restructuring can be delivered as an isolated intervention or as part of a multi-modal CBT. (See 'Cognitive-behavioral therapy' above.)

Evidence from a single clinical trial does not support cognitive restructuring as monotherapy for dental phobia [20]. The trial randomly assigned 52 patients with dental phobia to receive a one-hour session of cognitive restructuring, provision of information about dental health/treatment, or a wait-list control condition. The cognitive intervention was more effective than the control conditions in reducing dental anxiety and decreasing the frequency and believability of negative thoughts about dental treatment. However, patients receiving cognitive therapy still had moderate anxiety post-treatment and only 33 percent were considered to be clinically improved. After one year, there was no difference in dental anxiety between patients who did or did not receive the cognitive intervention.

Systematic desensitization — Systematic desensitization involves imaginal exposure to the feared stimulus coupled with muscle relaxation to cope with the anxiety. Clinical trials suggest that systematic desensitization is more efficacious than a control condition, but less efficacious than in vivo exposure in specific phobia [6,21,22]; the intervention has largely been supplanted by exposure therapy [23,24]. (See "Cognitive-behavioral therapies for specific phobia in adults", section on 'Systematic desensitization'.)

Coping strategies — Coping strategies used to treat dental anxiety include progressive muscle relaxation and applied relaxation.

Progressive muscle relaxation — The most common relaxation technique is progressive muscle relaxation, in which patients are instructed to practice tensing (five seconds) and relaxing (10 seconds) different muscle groups starting from top of the head down to the toes [25]. This exercise takes about 15 minutes and is practiced twice a day for one to two weeks until proficient. Then the tension part is eliminated and release-only relaxation of different muscle groups is practiced, which takes five to seven minutes. This is then followed by conditioned relaxation, in which the patients learn to relax the whole body at once on cue using the self-instruction “relax,” which further reduces relaxation to 30 seconds.

Applied relaxation — In applied relaxation, patients are taught to apply the skills of relaxation to anxiety-provoking situations as a coping strategy to counteract the physiological arousal experienced when anxious [25]. Patients are instructed first to relax on cue many times a day (15 to 20 times) to daily nonstressful situations. Then, they practice in anxiety-provoking situations. Patients are taught to recognize early signs of anxiety and apply relaxation even before entering an anxious situation. In contrast to in vivo exposure therapy in which patients remain in the anxiety provoking situation for a prolonged period of time (up to one to two hours) with the goal of habituation/extinction of the physiological arousal elicited, exposure in applied relaxation is much briefer (10 to 15 minutes) with the goal of coping with anxiety encountered in natural situations.

Relaxation therapy, a variation of applied relaxation, was more efficacious in reducing dental and overall anxiety compared with cognitive therapy in a randomized trial of 112 adults with dental phobia [7]. In the relaxation therapy condition, patients were trained in progressive muscle relaxation with the aid of electromyographic biofeedback to increase the patient’s ability to relax. Once proficiency in muscle relaxation was achieved, patients were trained to maintain relaxation during exposure to successively more anxiety-provoking dental situations (first video scenes, then progress to handling dental instruments). Although relaxation treatment was more effective, treatment completion rate was higher in the cognitive group compared with the relaxation group (74 versus 59 percent).

Hypnotherapy — Hypnotherapy for dental anxiety includes the following components [9]:

Progressive relaxation (see 'Progressive muscle relaxation' above)

Suggestions for deepening the hypnotic state, relaxation, and comfort

Instructions to the patient to imagine dental scenes and procedures in a successively more anxiety-provoking hierarchy

Suggestions to the patient, when in a stage of hypnosis, that they would no longer be afraid of the imagined dental situations

Clinical trials of hypnotherapy for dental anxiety do not show evidence of efficacy:

A clinical trial of 174 patients with dental phobia compared hypnotherapy with systematic desensitization, group therapy, or a waiting list control, finding that all three treatments led to similar reductions of anxiety compared with the control group [8]. Avoidance of dental treatment remained high among patients in all three groups. More than 50 percent of the sample dropped out of the study or did not follow through with dental treatment in the community within one year.

A trial randomly assigned 22 female patients with dental phobia to hypnotherapy or to a behavioral intervention involving exposure [9]. Exposure therapy resulted in a reduction in dental anxiety, while hypnotherapy did not. The small sample size and a drop-out rate of 44 percent limit the conclusions that can be drawn.

Medication — For most patients with dental phobia in which medication treatment is indicated, we suggest the use of nitrous oxide sedation over general anesthesia or benzodiazepines. General anesthesia can be useful for patients with dental phobia needing major dental work that would require multiple treatment sessions using other sedatives.

Nitrous oxide — Despite a paucity of efficacy data, nitrous oxide/oxygen is the sedation medication of choice in dental practice [26]. Administration of nitrous oxide has been associated with reduced anxiety and avoidance in patients with dental phobia in clinical trials but has not been compared with placebo in this population [27-29].

Advantages of nitrous oxide sedation include:

Pain relief

Inhalation method of delivery, eliminating the need for intravenous administration (particularly helpful in patients with injection phobia)

Rapid induction of sedation

Ability to titrate the level of sedation

Rapid elimination from the body such that patients are fully recovered within minutes after discontinuation

Relatively safe for use in all ages with minimal side effects

Contraindications of nitrous oxide sedation include early pregnancy, chronic respiratory conditions (eg, chronic pulmonary disease and cystic fibrosis), certain illnesses (eg, upper respiratory tract infections, pneumothorax) and following certain surgical procedures (eg, eye surgeries or tympanic membrane repair with graft). Sedation with nitrous oxide is discussed in more detail separately. (See "Procedural sedation in adults outside of the operating room: General considerations, preparation, monitoring, and mitigating complications".)

General anesthesia — Clinical experience suggests that general anesthesia is efficacious in dental phobia, but limited evidence suggests that it is less effective than behavioral therapy. A clinical trial randomly assigned 99 patients with dental phobia to receive either general anesthesia or behavioral therapy prior to a test procedure [30]. At the end of the study a greater proportion of patients receiving behavioral therapy were able to complete the procedure compared with patients assigned to receive general anesthesia (92 versus 69 percent). Although these results lacked a placebo group for comparison, the patients had previously avoided treatment for an average of 15 years.

General anesthesia is reserved for use as a last resort in dental treatment when other methods are not safe or feasible, or have not been effective [12]. Examples of patients who may receive general anesthesia include:

Patients who are not able to cooperate, communicate, or follow directions due to lack of maturity or due to a mental, physical, or medical disability

Patients who experience extreme anxiety that is too severe to tolerate exposure therapy and would otherwise require high levels of nitrous oxide or other sedating agents that may not be safe in an outpatient setting

Patients for whom the combination of local anesthesia and nitrous oxide was ineffective in alleviating pain

Patients who require significant surgical procedures

In a retrospective medical record study of 349 patients of mixed ages who received dental service in Finland, the top-ranked reasons for use of general anesthesia was extreme noncooperation with the dentist, dental fear, and extensive need for treatment [12].

Cooperation and tolerance of dental procedures may be especially difficult in certain adult populations, such as individuals with cognitive impairment, physical or mental disabilities [31], and medically compromised patients who are unable to cooperate with treatment or not able to tolerate oral sedatives or nitrous oxide [32]. In the last group of patients, providing comprehensive dental treatment in one single visit, rather than multiple outpatient visits, may be a safer and more tolerable option. A survey of 494 individuals with physical or cognitive impairment suggested a high level of dental fear. The option of general anesthesia may decrease barriers to dental treatment in this population [31].

Risks of general anesthesia in dental treatment include:

Prolonged sedation

Hypoxia, airway obstruction

Injury to teeth, oral and pharyngeal structures

Complications due to medical disease, cardiac arrest, and malignant hyperthermia [32]

Benefits of general anesthesia include behavioral control, ability to titrate medication, effectiveness when other forms of sedation fail, maintenance of intravenous access and patent airway, monitoring and support of vital functions, anxiety control, and ability to perform multiple procedures at one time [32].

Benzodiazepines — Benzodiazepines appear to be efficacious for sedation and anxiolysis in dental phobia but have disadvantages compared with other treatments. Clinical experience and limited evidence support efficacy. A clinical trial of 91 patients randomly assigned patients to receive midazolam, psychological treatment (consisting of information, cognitive restructuring, relaxation, and applied relaxation), or no treatment [10]. Fifty patients completed the trial, which found both interventions to decrease dental anxiety compared with no treatment. At two-month and one-year follow-up, decreased anxiety was only seen in patients who received psychological treatment, compared with patients who received no treatment. Clinical trials have found benzodiazepines to be effective in other specific phobias. (See "Pharmacotherapy for specific phobia in adults" and "Pharmacotherapy for specific phobia in adults", section on 'Medications'.)

Benzodiazepines, however, cause sedation and psychomotor impairment that can last for hours, in contrast to minutes for nitrous oxide (table 1). As described above, the clinical effects of benzodiazepines last only for that treatment episode, while the effects of exposure therapy can last for months or years. Administration of benzodiazepines for acute procedural anxiety is discussed separately. (See 'Approach to treatment' above and "Treatment of acute procedural anxiety in adults", section on 'Benzodiazepines'.)

BLOOD-INJECTION-INJURY PHOBIA — Blood-injection-injury phobia is characterized by the fear of seeing blood, receiving an injection, or of other invasive medical procedures [33]. We suggest first-line treatment for blood-injection-injury phobia with applied tension, a combination of muscle tensing and exposure therapy. (See "Acute procedure anxiety in adults: Epidemiology, clinical manifestations, and course", section on 'Blood-injection-injury phobia'.)

Applied tension — Applied tension is used to counteract the vasovagal fainting response associated with blood phobia [34-36]. Applied tension involves repeatedly tensing body muscles to increase blood pressure and prevent fainting when in the presence of the phobic stimulus (ie, with in vivo exposure).

In treatment with applied tension, the patient is instructed to tense the muscles in their arms, torso and legs and hold the tension until a warm feeling is experienced in the head, typically 10 to 15 seconds. The patient then releases the tension and waits for 20 to 30 seconds for the body to return to normal. The patient then practices this tension-release cycle repeatedly until they become skilled in the technique. Once the technique is mastered, the patient is instructed to use the technique in response to the early signs of a drop in blood pressure (eg, lightheadedness) during exposure practice to feared situations.

Several small randomized trials found that applied tension was more effective in blood-injection-injury type phobia compared with exposure alone or muscle tension alone, leading to reduced anxiety, avoidance, and fainting. The trials were limited by small sample sizes and yielded variable results [6,36]. As an example, 30 patients with blood-injection-injury phobia were randomly assigned to five sessions of applied tension, in vivo exposure alone, or muscle tension alone [37]. Greater rates of response were seen for applied tension and tension alone compared with in vivo exposure alone (90 and 80 versus 40 percent, respectively). Results were sustained on assessment one year later.

Other interventions — When there is a known history of fainting and the patient has not learned the applied tension technique, the patient should lie down during a procedure (eg, venipuncture), look away from the site of blood draw, and sit up slowly only after sensations of dizziness and fainting resolve.

There are no clinical trials of medication for blood phobia and, in our clinical experience, medication is not useful for the condition. Commonly used anxiolytics, such as benzodiazepines, similarly do not appear to affect the vasovagal phenomenon.

MRI CLAUSTROPHOBIA — For most patients with magnetic resonance imaging (MRI) claustrophobia, we suggest adjustment of the patient’s position in the MRI scanner. In patients where this approach is not effective, treatment with benzodiazepines is generally suggested, though in vivo exposure is a reasonable alternative for patients requiring multiple recurring MRIs. (See "Acute procedure anxiety in adults: Epidemiology, clinical manifestations, and course", section on 'MRI claustrophobia'.)

Nonmedication approaches

Positional adjustment — A simple strategy for managing MRI claustrophobia is to change the patient’s positioning in the scanner. This approach is feasible only for MRI scans where specific positioning is not critical to capturing the needed image. The patient should be positioned feet first in the scanner. Feet-first exams are less likely to be associated with a claustrophobic reaction compared with head-first exams [38]. Placing the patient in prone position can also be helpful. Prone positioning compared with supine positioning in the scanner is associated with a lower incidence of premature termination [39] and is less likely to result in a claustrophobic reaction [38]. An uncontrolled retrospective study suggests that positional adjustment is effective. The study of 1160 patients undergoing MRI scans included 19 patients who were initially unable to complete an MRI scan because of claustrophobia. After they were transitioned to a prone position, all 19 patients completed the scan [40].

Psychotherapies — For patients with claustrophobia not limited to MRI, or who require repeated MRIs and prefer psychotherapy, or have medical contraindications to benzodiazepines, we suggest treatment with in vivo exposure therapy over other treatments. If in vivo exposure is used for MRI claustrophobia, the therapy should ideally be conducted in an environment similar to that of an MRI suite. Two trials have found cognitive therapy and in vivo exposure therapy to be equally effective in the treatment of claustrophobia compared with placebo [41,42]. As an example, in a trial of 46 patients with claustrophobia, symptomatic improvement was maintained for one year in 81 to 100 percent of patients receiving exposure therapy, and 93 percent of patients receiving cognitive therapy, but only 17 percent of patients assigned to a waiting list control [42].

In cognitive therapy, distorted and negative beliefs about the MRI scanner, such as fear of suffocation, fear of machine causing harm, and fear of losing control in the scanner, should be identified and challenged [43].

An alternative psychotherapy for claustrophobia is interoceptive exposure, in which patients are exposed to the physical sensations of anxiety that are reproduced in a controlled setting. In a trial of 48 patients, interoceptive exposure was shown to have modest effects in decreasing the frequency of negative cognitions and physical sensations of claustrophobia in comparison with modification of negative cognitions, or a control condition [41].

Further study is needed to test whether these findings in claustrophobia can be generalized to MRI claustrophobia.

Medications

Benzodiazepines — If positional adjustment is not possible or ineffective, we suggest treatment of most patients with MRI claustrophobia with a benzodiazepine over other treatments. There are no controlled trials comparing a benzodiazepine with placebo in MRI claustrophobia. In an observational study of 1133 patients treated with a benzodiazepine prior to an MRI scan, sedation was achieved 89 percent of cases [44]. Sedation for MRI claustrophobia is generally safe. A study of 4761 patients had a complication rate of 0.4 percent [44]. The most common complication was oxygen desaturation; there were no fatalities.

To achieve sedation in a patient with (or likely to experience) MRI claustrophobia, a benzodiazepine is typically administered intravenously 15 minutes prior to the procedure or 30 minutes for oral formulations. Diazepam has a more rapid onset than lorazepam and alprazolam. As an example, 10 mg of oral diazepam is recommended for healthy adults [44]. A table provides dosing of oral and intravenous benzodiazepines commonly used in procedural sedation (table 1). Further details about the use of benzodiazepines for procedural anxiety, including MRI claustrophobia, are discussed separately, including dose adjustments for clinical subgroups, repeat dosing, and patient education about side effects and driving. Adverse effects of benzodiazepines are discussed separately. (See "Treatment of acute procedural anxiety in adults", section on 'Benzodiazepines' and "Pharmacotherapy for insomnia in adults", section on 'Benzodiazepine hypnotics' and "Safety of infant exposure to antidepressants and benzodiazepines through breastfeeding" and "Antenatal use of antidepressants and the potential risk of teratogenicity and adverse pregnancy outcomes: Selective serotonin reuptake inhibitors", section on 'Selective serotonin reuptake inhibitors plus benzodiazepines'.)

Medications under investigation — A small trial tested the use of propofol and dexmedetomidine for MRI claustrophobia. Propofol is an intravenous hypnotic drug and dexmedetomidine is an intravenous sedating agent that is an alpha-2 adrenergic receptor agonist. Propofol and dexmedetomidine are commonly used for induction and maintenance of general anesthesia and sedation of mechanically ventilated patients in intensive care unit settings [45,46]. Both are also used in sedating patients undergoing diagnostic or invasive procedures, but their use requires monitored anesthesia care [45,46].

A clinical trial of 30 patients with MRI claustrophobia in Malaysia found that intravenous propofol and dexmedetomidine were each effective in producing sedating and anxiolytic effects [47]. Both drugs reduced anxiety equally, but dexmedetomidine required longer time to achieve sedation and was associated with hypotension and bradycardia. Dexmedetomidine was given in a single loading dose of 1.0 mcg/kg over 10 minutes, followed by an infusion of 0.2 mcg/kg/hour and increased by 0.1 mcg/kg/hr until adequate sedation was achieved. Propofol 1 percent was given at rate of 1.5 mcg/kg, titrated at increments of 0.1 mcg/kg to achieve sedation.

Sedation with propofol and dexmedetomidine under monitored anesthesia care are reviewed in more detail separately. (See "Monitored anesthesia care in adults".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Anxiety and anxiety disorders in adults".)

SUMMARY AND RECOMMENDATIONS

Presentations of acute procedural anxiety are diagnosed as a specific phobia when the focus of the patient’s fear is specific to the procedure or its immediate effects (eg, fears of experiencing pain during dental treatment, of seeing blood during venipuncture, or of suffocating during a magnetic resonance imaging [MRI] scan). (See 'Introduction' above.)

General principles for treating specific phobias of clinical procedures include establishing a trusting relationship with the patient, educating them about their medical condition and reasons for the procedure, and identifying and addressing the aspect(s) of the procedure that are most concerning to them. Make the patient as comfortable as possible and give them as much control as possible during the procedure. (See 'General principles' above.)

For most cases of dental phobia, we suggest in vivo exposure as first-line treatment rather than medication or other interventions (Grade 2C). In vivo exposure can be provided as an independent modality or within the context of a broader cognitive-behavioral therapy. (See 'Approach to treatment' above and 'In vivo exposure therapy' above and 'Cognitive-behavioral therapy' above.)

For patients with dental phobia who prefer medication to psychotherapy or have one of the indications below, we suggest first-line treatment with nitrous oxide (Grade 2C). (See 'Approach to treatment' above and 'Nitrous oxide' above.)

Lack access to exposure therapy

Need emergency dental treatment

Experience anxiety that is too severe to tolerate exposure therapy

Failed previous, adequate trial of exposure therapy

General anesthesia should be reserved as a last resort for dental phobia, for use principally when other forms of sedation are not an option or not effective. (See 'Approach to treatment' above and 'General anesthesia' above.)

For patients with blood-injection-injury phobia, we suggest first-line treatment with applied tension (a combination of muscle tensing and exposure therapy) rather than medication or other interventions (Grade 2C). (See 'Blood-injection-injury phobia' above.)

Placing patients with MRI claustrophobia in the MRI feet first, or in a prone rather than a supine position, when feasible, can be helpful for some patients. When this approach is infeasible or ineffective, treatment with a benzodiazepine is generally suggested. In vivo exposure is a reasonable alternative for patients requiring multiple recurring MRIs. (See 'MRI claustrophobia' above and "Treatment of acute procedural anxiety in adults", section on 'Benzodiazepines' and 'In vivo exposure therapy' above.)

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Topic 83458 Version 21.0

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