Each patient will have an individualised  treatment plan including:

• the use of de-escalation techniques
• as required or discretionary oral medication as appropriate for the patient 
• the choice of IM medication where necessary

If IM administration is required the appropriate MHA documentation should be completed if applicable.

When IM sedation is administered, a doctor should be informed and available to attend the patient within 30 minutes if required.

Consider the potential for inadvertent high-dose antipsychotic therapy when prescribing IM antipsychotics.

When prescribing medication for use intramuscularly, write the initial prescription as a once-only dose, do not repeat it until the effect of the initial dose has been reviewed.

If the behavioural disturbance is thought to be related to 'excited delirium' then consider immediate referral to acute care (see RCEM guidance).

Recommended Treatment Choices (NICE Guidance NG10 2015)

• Midazolam (or Lorazepam, if used locally) or
• Haloperidol +/- Promethazine

Alternatives not recommended by NICE for the purpose of emergency IM treatment in acutely disturbed patients but may be considered where the use of haloperidol is inappropriate e.g. where there is a risk of prolonged QTc interval

• Aripiprazole
• Olanzapine

Use of lower doses in some patient groups e.g. elderly or debilitated.

Care must be taken in struggling patients to avoid inadvertent IV administration.

After an initial IM Administration:

• Nursing staff commence physical monitoring immediately after administration
• Repeat after 30-60 minutes if insufficient effect (exception: wait 1-2 hours after promethazine and 2 hours after olanzapine IM).
• Response to each dose should be documented in the patients’ care record
• Be aware of the total dose of medication administered over the last 24 hour

Midazolam 5mg-7.5mg 

• Midazolam is considered 1st choice due to significant increase in the cost of lorazepam injection.
• Maximum cumulative dose over 24 hours: 15mg
• ¼- ½ adult dose- In elderly (>60), physically ill or debilitated patients, individuals with renal, hepatic or cardiac function or chronic respiratory insufficiency.
• Monitoring for excessive sedation, respiratory depression, hypotension for at least 4 hours after last dose.
• Midazolam 10mg/2ml ampoules should be used for this indication, as it is a controlled drug (CD), it must be ordered in the ward CD order book, stored in CD cupboard and receipt/administration recorded in the CD register.

Lorazepam 2mg

• Maximum cumulative dose (oral+IM) over 24 hours: 8mg
• Useful when
  • Insufficient information to guide medication choice or patient is antipsychotic naïve
  • Patient is already on regular antipsychotic and haloperidol is contraindicated
  • Evidence of cardiac disease or no electrocardiogram (ECG) has been carried out

Risks with benzodiazepines:

• Respiratory depression or arrest
• Loss of consciousness
• Ensure flumazenil IV is available

Haloperidol 5mg

• Maximum cumulative dose (oral+IM) over 24 hours: 20mg
• Useful when
  • Patient is benzodiazepine tolerant or prescribed regular benzodiazepine
• Pre-treatment ECG required
• Ensure IM procyclidine available

Olanzapine 10mg

• Maximum cumulative dose (oral+IM) over 24 hours: 20mg
  • Adults: 5 – 10mg by intramuscular injection. A repeat dose of 5 – 10mg may be given after a
    minimum of 2 hours
  • Elderly: 2.5 – 5mg by intramuscular injection. A repeat dose of 2.5 – 5mg may be given after
    a minimum of 2 hours.
  • Adolescents: 2.5 - 5mg by intramuscular injection (depending on age, weight, previous
    exposure to antipsychotic medication, and whether has underlying neurodevelopmental
    disorder/LD). A repeat dose of 2.5 - 5mg may be given after a minimum of 2 hours.
    Maximum daily dose is 10mg - 20 mg (again dependent on above parameters and including
    any oral olanzapine
• No more than 3 injections should be given in 24 hours.
• Maximum treatment course is 3 days.
• If to be repeated wait 2 hours
• Wait one hour before administering an IM benzodiazepine
• If benzodiazepine already given, the clinical status of the patient should be assessed and consultant advice obtained prior to IM olanzapine being administered

Aripiprazole 9.75mg

• Maximum cumulative dose (oral+IM) over 24 hours: 30mg

Risks with antipsychotics

• Cardiovascular complications e.g. QTc prolongation especially with haloperidol
• Reduction in seizure threshold
• Adverse side effects e.g. restlessness (akathisia), acute rigidity (dystonia) and involuntary movements (dyskinesia)
• Altered consciousness
• Neuroleptic malignant syndrome (increased temperature, sweating, restlessness, altered consciousness or marked muscular rigidity). If suspected: stop all antipsychotics drugs, cool the patient and get an urgent medical assessment

Promethazine 50mg

• Maximum cumulative dose over 24 hours: 100mg
• Useful when
  • Patient is benzodiazepine tolerant or if there is concern over using antipsychotics
• Risks
  • Contraindicated with CNS depression and those who have taken MAOIs within the past 14 days
  • Cautions include respiratory conditions, coronary artery disease, epilepsy and hepatic/renal insufficiency
  • Possibility of QTc prolongation
  • Reduced seizure threshold

After IM sedation the ward team monitor the following at least every hour until the patient is ambulatory:

• Adverse effects
• Pulse
• Blood pressure
• Respiratory rate
• Temperature
• Level of hydration
• Level of consciousness

Monitor every 15 minutes if the BNF maximum dose has been exceeded or the patient:

• Appears to be asleep or sedated
• Has taken illicit drugs or alcohol
• Has a pre-existing physical health problem
• Has experienced any harm as a result of any restrictive intervention
• Has been given haloperidol in combination with other drugs know to prolong QTc

Where full monitoring is impractical, clearly document the reasons why and ensure minimum observation of respiration and level of consciousness.