Is it permissible in Islam to use a medication that carries a high risk of leading to the patient's death, knowing that there is severe pain that sometimes causes delay in prayer?

A Muslim is not permitted to consume anything that will certainly harm him, or is highly likely to harm him, for he is commanded to preserve his body. Harm is not alleviated by something similar, thus it is forbidden to treat an illness with something whose harm is greater than the harm of the illness itself. Patience in enduring pain and seeking reward for it increases one's recompense and expiates sins. "No fatigue, nor illness, nor anxiety, nor grief, nor harm, nor sorrow befalls a Muslim, even a thorn that pricks him, but Allah expiates some of his sins by it." Indeed, a woman from the people of Paradise chose patience with epilepsy in exchange for Paradise. Sedatives and painkillers can cause serious harm, and pain can be alleviated through nutrition programs and exercise. One should consult more than one specialized physician, and despite all of this, exercise patience and contentment with Allah's decree, and make abundant supplication.