The state and the defense presented their final witnesses Tuesday in the manslaughter trial of Dixie Denise Villa, accused of giving a fatal dose of diphenhydramine, the antihistamine found in Benadryl, to a 7-month-old infant.

While the jury was outside the courtroom, it appeared Villa might take the stand Tuesday afternoon in her own defense.

But her court-appointed attorney, Megan Kau, said it hinged on whether the state would be allowed to cross-­examine Villa, a former Navy wife, about an alleged cover-up attempt that she ran an unlicensed day care at her home in military housing at Aliamanu Military Reservation.

Deputy Prosecutor Tiffany Kaeo argued the state should be allowed to cross-examine Villa about her alleged instructions to Briana Calderon, a friend of her daughter, to lie to military police just three days before Abigail Lobisch died.

Kau said military police showed up at Villa’s home on Feb. 21, 2019, while she was out and her daughter Ariana Rivera and Calderon were visiting. Calderon testified that Villa told her to say that one or two of the children at Villa’s day care were Calderon’s kids.

Kau said it would be prejudicial to her client, but Oahu Circuit Judge Fa‘auuga To‘oto‘o ruled that the prosecution would be allowed to ask about the incident.

With her credibility on the line, Villa declined to testify. So jurors will not learn at trial about the incident or the allegation she ran an unlicensed day care, which violates federal military housing rules.

The state and the defense will give their closing arguments today.

State’s witness Dr. Paul Eakin, a pediatric emergency physician at Kapi‘olani Medical Center for Women &Children and an associate professor at the University of Hawaii’s John A. Burns School of Medicine, testified that diphenhydramine toxicity, or poisoning, is fairly common in the emergency room.

He said he would contact poison control if he had a case. Symptoms are easy to notice and include a dry mouth; dilated pupils; an elevated body temperature; a racing heart; shallow, slow breathing; a pale, bluish color; and feeling lethargic.

Eakin said to reach the 2,400 nanograms per milliliter found in the heart blood of baby Abigail, one would have to take a dose of 30 to 40 times the usual oral dose.

It is not marketed as a sleep aid for infants because in children it crosses the blood-brain barrier easily and can leave a child confused, with hallucinations.

Symptoms could appear within 30 minutes to three or four hours, and could stay in the system for more than 10 hours, Eakin said.

Eakin’s testimony discounted the defense’s claim that Anna Lobisch, the baby’s mother, might have caused the poisoning because she took Tylenol PM while breastfeeding.

Kaeo asked Eakin, “Is it possible for an infant to ingest (in breast milk) a fatal amount of diphenhydramine?”

“No, not in my experience,” he said.

He said that the amount of the antihistamine would be minimal in breast milk.

Eakin said he would not send home diphenhydra­mine (invented in 1946) or recommend even the topical form below age 2 because of the harmful side effects. He said antihistamines developed more recently such as ceterizine, marketed as Zyrtec, are safer for babies 6 months and older but are not available in intravenous form because they are too expensive.

A single therapeutic level dose would be 60 to 80 ng/ml for an infant, given intravenously in an emergency room setting for a systemic reaction such as anaphylactic shock due to a food allergy, difficulty breathing or vomiting.

Kau, in cross-examining Eakin, said since he said it would take 30 times the usual oral dose of diphenhydramine to reach the level of 2,400 ng/ml as was found in the heart blood of baby Abigail, that he perform a “science experiment.” She told Eakin to pour 30 doses of liquid Benadryl for adults and children 12 and older, cup by cup, into a glass measuring cup, and to count each one, and asking him if he needed more bottles, obviously for effect.

Then she allowed jurors to compare 4 ounces of formula, a reasonable amount to give an infant, with the Benadryl.

But in redirect, Kaeo showed the “science experiment” had an obvious flaw.

Kaeo asked whether the dosage amount would be a lot larger for adults than what is recommended to give an infant. The cup he was provided by Kau was an adult dose.

He said, “It’s about 10 times what you’d give to an infant.”

Also, none of the photos the defense had shown of products containing diphenhydramine were for children.

The defense’s expert witness, Okorie Okorocha, who presented himself as a forensic toxicologist but was not board-certified, was questioned by Deputy Prosecutor Joel Garner as to the validity of his master’s degrees in toxicology and pharmacology. He obtained those degrees from online classes, requiring no graduate theses, from a school that is not an accredited college under the American Academy of Forensic Sciences.

Okorocha countered that he wrote seven published articles. But they were either commentary, not peer-reviewed, or were published in law reviews, Garner said.

Garner said most of Okorocha’s work has been done testifying at an average of a jury trial a week, and is billing the state $400 an hour for a total of $400,000.

He also has a law degree and says he practices as a lawyer, but in three cases on Westlaw, a legal research service and database for lawyers, he was found not to be a credible expert witness by courts in California.

Over the state’s objection, the judge allowed his testimony as an expert witness.

Okorocha said he disagreed with Dr. Jon Gates, who performed the autopsy, taking heart blood, and said he should have tested the brain.

“Diphenhydramine does not produce death in hours, so it’s heart, lungs and brain that is important,” he said.

He said the preferred sampling site would be the brain.