**15. Treatment of delirium**

Nonpharmacological measures are essential. With the environment, education and support should be carried out with the family group and close friends. Sleep hygiene, restoration of circadian rhythms, adequate environment with natural light, reducing extreme light, acoustic or thermal stimuli; avoiding if possible or at least minimizing any physical, manual or mechanical restriction, hearing and visual aids. Facilitate reorientation, transmit security and confidence to both family members and patients [57].

Neuroleptics are the drugs of choice and among them, haloperidol is the most used: it can be administered orally, intravenously, intramuscularly, and subcutaneously. Low doses of haloperidol 1–10 mg/day may usually be necessary. If it is started by the subcutaneous route, it can be started with a dose of 1.5–2.5 mg every 8 hours. It is necessary to schedule a rescue dose of 1.5–2 mg subcutaneous every 20–30 minutes. If necessary, at least 3 rescue doses can be used before switching to another, more sedating neuroleptic [49, 56, 57].

Chlorpromazine has a greater anticholinergic and sedative effect than haloperidol. However, its use is avoided subcutaneously because it is very irritating. It starts with a dose of 12.5 mg PO, IV, and IM every 4–12 hours. The same rescue dose can be used every 15–20 minutes up to a maximum of three doses before considering the use of a benzodiazepine [49, 56].

Levomepromazine has a greater sedative effect than chlorpromazine and can be indicated when the use of the subcutaneous route is needed and haloperidol is ineffective. It begins with doses of 12.5 mg PO, IM, IV, and SC every 4–12 hours, with rescue doses of 12.5–25 mg every 15–20 minutes [49, 56].

Olanzapine is an atypical neuroleptic with anxiolytic and sedative effects. The initial dose is 2.5–10 mg every 12 hours.

Risperidone is another atypical neuroleptic and can be used PO in the form of tablets or orodispersible and as an oral solution. The dose ranges between 0.25–3 mg/12–24 hours.

Benzodiazepines are indicated when neuroleptics fail to control agitation, when quick deep sedation is required, and as the first choice when delirium is precipitated by alcohol withdrawal or sedatives. Midazolam is commonly used since it can be administered by any route. The initial dose is 2.5–5 mg sc/ev every 5–10 minutes followed by a continuous infusion either sc or ev [49, 56].

In refractory cases of agitation, the use of anesthetic agents such as barbiturates or propofol may become essential.

Those cases in which the underlying cause is the use of psychotropic drugs, including opioids, and dehydration have a particularly good prognosis. We must not forget that 50% of cases of delirium are reversible, so an early and accurate diagnosis is essential.

## **16. Conclusions**

Cancer is the principal cause of death worldwide and mental health pathologies represent a public health concern due to its high prevalence, morbimortality, and long-term disability.

The three most critical psychiatric disorders in terminally ill cancer patients are anxiety, depression, and delirium. Despite their frequency, they tend to go undiagnosed and undertreated.

The comorbidity between cancer and psychiatric disorders generates several complications, ranging from non-adherence to any treatment, social isolation of the patient, greater symptoms and suffering, increased complications during recovery from surgery, high risk of disease progression and decrease of quality of life and other issues being observed in terminally ill cancer patients. We must bear in mind that 50% of all cases of delirium are reversible, so early, and accurate diagnosis is paramount.

The early detection and management of both psychic and psychological symptoms will improve patients' quality of life and good death, positively impacting not only the patients but also their caregivers.

Treatment of mental health problems in cancer patients is no different than in other patients. The recommendation is always to provide a multidisciplinary intervention that includes medical treatment of the underlying disease as well as of the mental health (psychiatry and psychology), social work support, physiotherapy and others that speed up the recovery process or delay the deterioration of the patient's health.

Psychotherapeutic interventions should also be included for family and support group to help maintaining and improving the quality of life of these patients and allow them and their families to transition to death with dignity.
