Orlando, Fla. ? First there is pain — brief and surging — then collapse.

The muscles give way, and people hit by Taser guns become temporarily immobile.

The guns give out an electrical jolt, releasing about 50,000 volts in a five-second burst. Some have questioned whether that shock can be lethal, with new concerns arising from the recent death of a Lake Mary, Fla., man a day after Orlando, Fla., police subdued him with a Taser gun.

But both doctors and the stun gun’s maker dismiss the notion as groundless — and fueled by a lack of understanding of the science behind the weapons.

They say Tasers do not affect the heart or the brain. They cannot kill by themselves and do not trigger other problems that ultimately lead to death, its advocates say.

When someone dies from an electrical shock, it happens immediately, doctors say. The electricity does not linger in the body and cause death sometime afterward.

Nationwide, at least 50 people have died after being been hit by a Taser. In some cases tracked by the gun’s maker, Taser International, medical examiners found the cause of death to be illicit drugs, head trauma or other causes unrelated to the Tasers.

An often-cited concern is that people who are on drugs such as cocaine or PCP may be vulnerable to bad reactions from the Tasers, but that has not been proven.

When fired, the guns release two barbed “prongs” that can attach to the person’s skin or clothing. The resulting electrical jolt is delivered in energy measured in units called “joules.” The two Taser guns on the market today give off either 1.76 joules per pulse or 0.36 joules per pulse, said Steve Tuttle with Taser International, the manufacturer.

For comparison, doctors hit patients with 150-450 joules when they are trying to shock a stopped heart back into action. The smaller jolt from a Taser, doctors say, cannot affect the heart or the brain, even if the person is hit repeatedly.