From the Guidelines
Medications such as antipsychotics, antiemetics, and certain antibiotics can cause restlessness and agitation in patients, requiring treatment with diphenhydramine (Benadryl) to calm them down. These reactions are often due to the medications' effects on dopamine pathways in the brain or histamine release. Antipsychotics like haloperidol, chlorpromazine, and prochlorperazine can cause acute dystonic reactions and akathisia (intense restlessness) 1. Antiemetics such as metoclopramide and promethazine can produce similar effects. Some antibiotics, particularly fluoroquinolones like ciprofloxacin, may cause central nervous system excitation in certain patients 1. Diphenhydramine works effectively for these reactions because it blocks histamine receptors and has anticholinergic properties that counteract the dopamine blockade causing the symptoms.
The typical treatment dose is 25-50mg of diphenhydramine given intravenously or intramuscularly, which usually resolves symptoms within 15-30 minutes 1. Patients with these reactions should be monitored for respiratory depression, especially if they've received other sedating medications. It's essential to note that the use of antipsychotics and benzodiazepines can themselves cause increased patient agitation and delirium, and their use should be carefully considered and monitored 1.
Some key points to consider when managing agitation in patients include:
- Identifying the underlying cause of agitation
- Using verbal restraint strategies to de-escalate the situation
- Considering the use of medications such as benzodiazepines or antipsychotics
- Monitoring patients for potential side effects and adverse reactions
- Using the lowest effective dose of medication for the shortest period possible 1.
In terms of specific medications, midazolam and lorazepam are commonly used to manage agitation, with suggested starting doses of 2.5 mg and 1 mg, respectively 1. However, the use of these medications should be tailored to the individual patient's needs and circumstances. Overall, the goal of treatment is to prioritize the patient's safety and well-being, while also addressing the underlying cause of agitation.
From the FDA Drug Label
Central Nervous System: Quinolones, including ciprofloxacin, may also cause central nervous system (CNS) events, including: nervousness, agitation, insomnia, anxiety, nightmares or paranoia. The medication ciprofloxacin given in the ER can cause restlessness and agitation, requiring diphenhydramine (Benadryl) to calm the patient 2.
- Key points:
- Ciprofloxacin may cause CNS events such as agitation
- Diphenhydramine may be used to calm the patient
- This is a potential side effect of the medication, and patients should be monitored for these symptoms.
From the Research
Medications Causing Restlessness and Agitation
Medications given in the Emergency Room (ER) that can cause restlessness and agitation, requiring diphenhydramine (Benadryl) to calm the patient, include:
- Metoclopramide, which can cause akathisia, an unpleasant symptom complex characterized by restlessness and agitation 3
- Haloperidol, a dopamine receptor antagonist used to treat patients with psychotic disorders, which can cause extrapyramidal symptoms, including restlessness and agitation 4, 5, 6
- Other neuroleptics, which can cause serious adverse effects, including extrapyramidal symptoms and akathisia 7
Treatment of Restlessness and Agitation
Diphenhydramine is often used to prevent or treat restlessness and agitation caused by these medications. However, the effectiveness of prophylactic diphenhydramine in reducing neuroleptic side effects is still controversial 7. Some studies suggest that diphenhydramine may decrease subjective restlessness in patients administered high doses of metoclopramide 3 or haloperidol 5, while others found no significant effect on the incidence of extrapyramidal symptoms or akathisia 7.
Key Findings
- Metoclopramide can cause akathisia, which can be treated with diphenhydramine 3
- Haloperidol can cause extrapyramidal symptoms, including restlessness and agitation, which can be treated with diphenhydramine 4, 5, 6
- Prophylactic diphenhydramine may decrease subjective restlessness in patients administered high doses of metoclopramide or haloperidol, but its effectiveness in reducing neuroleptic side effects is still controversial 3, 5, 7