ABH Gel Dosing
The standard recommended dose of ABH gel is 0.5-1.0 mL applied topically to the wrists, containing 2 mg lorazepam, 25 mg diphenhydramine, and 2 mg haloperidol per 1.0 mL dose.
Critical Evidence-Based Caveat
However, you should NOT use ABH gel for nausea and vomiting management. The highest quality pharmacokinetic study demonstrates that ABH gel is not absorbed through intact skin at therapeutic levels 1. In a controlled study of 10 healthy volunteers, no lorazepam or haloperidol was detected in plasma samples, and diphenhydramine showed only erratic, subtherapeutic absorption (maximum 0.30 ng/mL) 1. This means the gel cannot achieve the systemic drug concentrations necessary for antiemetic efficacy.
Formulation Details
When ABH gel is compounded, the standard 1.0 mL dose contains:
- Lorazepam: 2 mg
- Diphenhydramine: 25 mg
- Haloperidol: 2 mg
The gel is typically applied to the volar (inner) surface of the wrists and rubbed in by the patient 1.
Why This Matters Clinically
While pilot studies suggested subjective benefit 2, the pharmacokinetic data definitively shows inadequate absorption 1. Any perceived benefit is likely placebo effect. More recent research on Carbopol-based formulations shows improved absorption compared to PLO gel, but still achieves only marginal therapeutic levels 3.
For actual nausea/vomiting management, use systemically absorbed routes:
- Oral medications when tolerated
- Intramuscular or intravenous administration for acute symptoms requiring rapid control
If using these same medications parenterally for agitation (not nausea), evidence-based dosing differs significantly:
- Haloperidol: 0.5-1 mg IM/IV for elderly 4; 1-2 mg for adults 5
- Lorazepam: 0.05-0.1 mg/kg IM/IV (max 4 mg) 6
- Diphenhydramine: 25-50 mg IM/IV 7
The topical gel formulation simply cannot deliver these medications effectively for systemic therapeutic effect.