These medications are used to treat anxiety symptoms associated with various disorders like generalized anxiety disorder, PTSD, agoraphobia, panic disorder, and phobias. Anxiolytics include beta-blockers, especially propranolol, buspirone, certain antihistamines like hydroxyzine (Atarax) and diphenhydramine (Benadryl), antidepressants, and sedative-hypnotics.
Buspirone (BuSpar, Vanspar) modulates the levels of serotonin and dopamine in the brain. Adverse effects include dizziness, nausea, diarrhea, headache, confusion, rash, weakness, and increased sweating. It should not be taken with grapefruit juice and is contraindicated with MAOIs.
Sedatives and hypnotics are drugs used to decrease stress and anxiety and to treat insomnia. They are also known as tranquilizers or sleeping pills. They include barbiturates, benzodiazepines, other drugs like zolpidem etc.
Barbiturates increase GABA or gamma aminobutyric acid in the brain which helps in promoting sleep and calmness. Examples include phenobarbital (Sezaby), pentobarbital and amobarbital (Amytal sodium). They have high addiction and dependence potential. Hence they are not preferred as sedatives-hypnotics. They are mainly used as anesthetics and antiepileptics. They may cause respiratory depression. Barbiturates are controlled substances and are classified under Schedules II to IV.
Benzodiazepines activate GABA-A receptors in the brain and affect conductances of chloride channels. GABA-A promotes slowing down of the brain impulses leading to increased sleep, seizure control, muscle relaxation, and reduced stress. They can have serious and life-threatening adverse effects, including respiratory depression, especially when combined with alcohol or other respiratory depressant medications, dependence, drowsiness, confusion, headache, nausea, vomiting, and coma. Patients taking benzodiazepines chronically may develop tolerance to their effects. Benzodiazepines differ by their half-lives, which affects how long the drug will remain in the body. Those with short to intermediate half lives between 5-20 hours include alprazolam, midazolam, bromazepam, clonazepam, lorazepam, oxazepam and temazepam. Those with long half-lives above 20 hours, some with half-lives as high as 80-100 hours include diazepam, clorazepate, and chlordiazepoxide. Commonly prescribed benzodiazepines include diazepam (Valium), alprazolam (Xanax), triazolam (Halcion), lorazepam (Ativan), clonazepam (Klonopin),elprazolam (Prosom), flurazepam (Dalmane), temazepam (Restoril) and midazolam (Versed). They are controlled substances and are classified under DEA Schedule IV.
Flumazenil (Anexate, Mazicon, Lanexat, Romazicon) is an antagonist to benzodiazepine receptors. It is used to reverse benzodiazepine overdose. It may cause seizures, slow heart rate, agitation, sweating, confusion, blurred vision, and hypertension. Flumazenil is contraindicated with TCAs as it induces seizures and is not effective at reversing benzodiazepine overdose.
There are medications that are not barbiturates or benzodiazepines that are used as sedative-hypnotics. Common ones include zolpidem (Ambien), eszopiclone (Lunesta), zaleplon (Sonata), ramelteon (Rozerem) and suvorexant (Belsomra). Drowsiness, dizziness, and tiredness are common adverse effects of all sedative-hypnotics. Alcohol enhances the adverse effects of all sedatives and hypnotics and is dangerous to be taken together. Zolpidem has a similar mechanism of action as benzodiazepines, as it modulates the activity of the GABA receptor in the brain. It has a high abuse and misuse potential. Dangerous sleep behaviors like sleepwalking, memory loss, and unusual activities while not fully awake, of which the patient did not have any recollection, like driving, cooking, etc., have been observed while taking zolpidem. Eszopiclone has a similar mechanism of action and adverse effect profile like zolpidem. Zaleplon is a short-acting drug with a mechanism of action resembling benzodiazepines, but it is more selective for the receptor type. Adverse effects are similar to zolpidem.
Suvorexant is an orexin receptor antagonist. Orexin promotes wakefulness and suvorexant blocks that to cause sleepiness. Unusual adverse effects include temporary inability to speak and temporary leg weakness also known as sleep paralysis. Ramelteon is a melatonin receptor agonist. It may cause a severe allergic reaction and angioedema with difficulty breathing.