Hydroxyzine is an antihistamine that reduces the effects of the natural chemical histamine in the body. Histamine can cause itching and hives on the skin. Hydroxyzine can be used to treat allergic skin reactions such as hives and contact dermatitis. Hydroxyzine also reduces the activity of the central nervous system, so it can also be used as a sedative to treat anxiety and tension. It is also used in combination with other drugs given during and after general anesthesia.
Hydroxyzine is a first-generation histamine H1 receptor antagonist of the diphenylmethane and piperazine classes and exhibits sedative, anxiolytic, and antiemetic properties. First developed in 1955, it remains a relatively common treatment for allergic conditions such as pruritus, urticaria, skin conditions, and histamine-mediated itch. Cetirizine, the active metabolite of hydroxyzine, can also be used as an active ingredient in allergy medications and is responsible for much of the antihistamine action of hydroxyzine. Hydroxyzine is also used for generalized anxiety disorder, psychoneurotic stress, and other conditions accompanied by anxiety symptoms.
Hydroxyzine comes from a group of drugs called diphenylethanes. Hydroxyzine is classified as a histamine (H1) blocker, but it also has sedative, antiemetic, antispasmodic, and anticholinergic properties. Two forms of the drug are available: hydroxyzine hydrochloride (Atarax) and hydroxyzine pamoate (Vistaril). Hydroxyzine is the most common oral sedative in pediatric dental practice, with 50% of pediatric dentists surveyed using one or both drugs.
The sedative effect of hydroxyzine is not due to cortical inhibition. It is believed that it inhibits some nuclei of the hypothalamus and extends its action to the peripheral sympathetic part of the autonomic nervous system.
After oral administration, hydroxyzine is rapidly absorbed from the gastrointestinal tract, and the clinical effect is observed within 15–30 minutes. The maximum clinical effect occurs after 2 hours, and the duration of action is approximately 3-4 hours.
The oral liquid form of hydroxyzine hydrochloride tastes better to most patients than the liquid form of hydroxyzine pamoate. This fact is especially important in pediatric dentistry.
When these drugs are prescribed in combination with opioids or barbiturates, the dose should be reduced by 50% because the depressant effects of opioids and barbiturates are enhanced by hydroxyzine.
Indications for the use of hydroxyzine include general treatment of long-term anxiety and tension, management of anxiety and tension when the underlying stress is temporary (eg, dental or other surgical procedures), and preoperative management of anxiety and tension. providing sedation and reducing anxiety and restlessness. Patients at cardiac risk and treatment of nausea and vomiting. Hydroxyzine is metabolized in the liver and excreted in the urine.
In dental practice, the use of hydroxyzine as a single drug is limited to the treatment of children with mild to moderate phobias. It is often used in combination with meperidine or chloral hydrate to treat more fearful pediatric patients.
The incidence of side effects is very low, the most commonly observed being transient drowsiness. Fatal overdose of hydroxyzine is extremely rare, and withdrawal reactions following long-term treatment have not previously been reported.
Contraindications include previous hypersensitivity to hydroxyzine.
Hydroxyzine enhances the inhibitory effect on the central nervous system of drugs such as barbiturates, opioids, alcohol, sedative-hypnotics, and anxiolytics. If these drugs are prescribed concomitantly with hydroxyzine, the dosage should be reduced by 50%.
Patients receiving hydroxyzine should be warned against driving or driving dangerous machinery. Children receiving hydroxyzine should be supervised by a parent or guardian for the remainder of the day.
Doses for adults range from 25 mg three times daily to 100 mg four times daily. For children under 6 years of age, the dose is 2 mg/kg per day orally in divided doses every 6 to 8 hours. Children 6 to 12 years: 12.5 to 25 mg orally every 6 to 8 hours. The preoperative dose of the drug for adults is 50 to 100 mg 1 hour before surgery.
When hydroxyzine is used as the sole agent for anxiety control in pediatric dentistry, the oral dose of hydroxyzine is 1.1 to 2.2 mg/kg. The dose of hydroxyzine should be reduced by 50% when used concomitantly with other CNS depressants such as meperidine or chloral hydrate.
Hydroxyzine hydrochloride, Atarax (Roerig): tablets of 10, 25, 50, and 100 mg. 10 mg/5 ml (0.5% alcohol) syrup. Hydroxyzine pamoate, Vistaril (Pfizer): 25, 50, and 100 mg capsules. oral suspension 25 mg/5 ml.
Hydroxyzine is an antihistamine that blocks H1 and muscarinic receptors. Ferreri et al. (1995) found that hydroxyzine was effective in treating GAD after 1 week of treatment in a placebo-controlled study and maintained improvement throughout the study. No rebound symptoms were observed after discontinuation of use. Lader and Scotto (1998) found that in a double-blind, placebo-controlled study, hydroxyzine and buspirone were significantly superior to placebo on both primary and important secondary outcome measures assessed by patients and physicians. Significant sedation limits the use of hydroxyzine in clinical practice. Another downside is that hydroxyzine has no effect on depression, a disorder commonly associated with GAD.
Hydroxyzine is an antihistamine that causes sedation by inhibiting histamine receptors in the hypothalamus. It also has anticholinergic effects, inhibiting salivary flow and causing dry mouth. It does not have specific effects on anxiety, but may produce anxiolysis through drowsiness. It has a rapid onset of action, peaks after 2 hours, and has an average half-life of 3 hours. It is available as hydroxyzine hydrochloride and hydroxyzine pamoate.
Medicine: tablets, elixirs.
Dosage: 0.5-1.0 mg/kg.
Side effects: Prolonged drowsiness, ataxia, dry mouth. Paradoxical reactions may occur in children when sedatives are prescribed.
Hydroxyzine, an antihistamine used to treat IC, prevents mast cell degranulation, which is responsible for IC symptoms. It is particularly beneficial for patients with allergies or mast cells identified on bladder biopsy. A study showed a 40% reduction in IC symptoms with hydroxyzine, which increased to 55% in patients with allergies. It can be taken alone or with pentosan polysulfate, starting at 10-25 mg at bedtime and gradually increasing to 50-75 mg. Hydroxyzine also helps with nocturia and other IC symptoms due to its sedative and anxiolytic effects.
Oral sedation is a valuable technique in pediatric dentistry, although it is not completely effective. It has a 40% to 50% failure rate in young children seeking moderate sedation. Unlike other methods, it does not require the use of needles or nasal hoods. Previously, parents would give oral medication to their children at home, but this is not recommended due to the risk of accidental overdose.
Taking oral sedatives within the confines of the dental office is even more recommended. Patients will have an appointment approximately one hour before treatment and the dentist will prescribe oral medications. Another consideration when administering medications in the office is patient monitoring. Staff should check children regularly, even if the office is busy (children may still be in the reception area with their parents or carers). In addition, the busy office environment makes it difficult to provide adequate sedation. During this waiting period, a calmer and more relaxed environment is preferred. A quiet room should be used where the patient and parents can remain while oral medications are administered and while the drug is active.
Young children may not tolerate tablets or capsules well, and parents may have to wrestle with the child to give the medication. Obviously, this behavior is not recommended if the goal is to relax the patient. Many medications administered orally to children are available in the form of elixirs or syrups, which are considered more palatable to patients. If a child refuses to take liquid medicine from a spoon, the medicine is administered through an irrigation syringe, with the medicine being injected into the buccal vestibule rather than into the patient’s throat.
Medicines that have an unpleasant taste or odor can be mixed with other products. Orange juice is often used. However, adding chemicals can change the taste. Acetaminophen (Tylenol) elixirs are also often used to mask the taste of oral medications. For young children, medications may be mixed with applesauce, jelly, baby food, or yogurt, which may adversely affect the absorption of the medication from the gastrointestinal tract. Midazolam syrup taken orally has become a popular sedative 15 and fentanyl is added to lozenges 16 .
The drugs most commonly prescribed orally in pediatric dentistry are chloral hydrate, hydroxyzine, diazepam, midazolam,13,17 the combination of chloral hydrate and promethazine, the combination of meperidine and chloral hydrate, hydroxyzine, diazepam, or promethazine. The pharmacology of these drugs is discussed in Chapter 7. Here we discuss the use of these drugs in children.
The use of chloral hydrate in pediatric dentistry in the United States has declined due to the introduction of new, more effective drugs such as midazolam. Chloral hydrate is most effective in very young patients or people with mental or physical disabilities. It can be taken orally as a capsule, elixir, or rectal suppository and is most effective in treating mild to moderate anxiety. The usual oral dose of the elixir is 500 mg/5 ml (1 teaspoon).
Initial dose. Chloral hydrate is administered 30–45 minutes before the scheduled dose. The patient was not allowed to eat or drink anything for 2 hours.
Doses of chloral hydrate range from 500 to 2000 mg on a milligram per kilogram basis, with a typical range of 750 to 1500 mg (Table 35-3). The elixir-type chloral hydrate usually contains orange or lemon syrup to mask the bitter taste. Chloral hydrate has an unpleasant taste and may cause gastrointestinal upset, so it must be diluted further with water, orange juice, or acetaminophen before administration. Chloral hydrate should not be diluted or added to alcohol. The duration of action of chloral hydrate is less than 1 hour.