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| [[Category: Drugs]][[Category: typical antipsychotic ]] | | [[Category: Drugs]][[Category: Typical Antipsychotic ]] |
| '''Haloperidol'''(中文:[[ ]]) is a typical antipsychotic medication. It is used in the treatment of various psychoses including:
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| *Schizophrenia
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| *Bipolar disorder
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| *Delirium
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| *in Tourette’s syndrome and severe tics
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| *in intractable hiccups
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| *in severe anxiety including for sedation of patients in intensive care or palliative care
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| *in the management of nausea and vomiting of various causes
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| It may be used by mouth. A long-acting formulation may be used as an injection every 4 weeks in people with schizophrenia, who either forget or refuse to take the medication by mouth.
| | [[:Category: Antipsychotic Drug | '''Antipsychotic Drug''']] |
| Doses are expressed in terms of the equivalent amount of haloperidol. Haliperidol decanoate 141 mg is equivalent to about 100 mg of haloperiodl.
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| Dosages should be reduced in elderly or debilitated patients; a usual starting dose is half the normal adult dose.
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|
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| ==Pronunciation==
| | '''Drug class: [[:Category: Typical Antipsychotic | Typical Antipsychotic]] |
| ===Haloperidol 1.5mg===
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| [[File:Haloperidol 1.5mg.mp3]] | |
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| ===Haloperidol 10mg=== | | '''Haloperidol (HALDOL)''' (中文:[[氟哌啶醇]]) |
| [[File:Haloperidol 10mg.mp3]]
| | ==Common Strengths of Haloperidol Tablet== |
| | Haloperidol are available in the following strengths: |
| | *Tablets: 1 mg, 1.5 mg, 5 mg, 10 mg, 20 mg |
| | *Oral drops: 2 mg/mL |
| | *Injectable solution: 5 mg/mL, 50 mg/mL and 100 mg/mL (decanoate) |
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| ===Haloperidol 1mg=== | | ==Drug Trade Names of Haloperidol Tablet== |
| [[File:Haloperidol 1mg.mp3]]
| | *Haldol |
| | *Serenace |
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| ==Drug Names== | | ==Drug Usage== |
| | *Treatment of schizophrenia and other psychoses |
| | *Control of tics and vocal utterances in Tourette's disorder |
| | *Management of agitation, delirium, and acute psychosis |
| | |
| | ==Mechanism of Action== |
| | Halperidol is a potent dopamine D<sub>2</sub> receptor antagonist in the brain. |
| | |
| | ==Route of Administration== |
| | *Oral (tablets and liquid) |
| | *Intramuscular injection |
| | *Intravenous injection |
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| | ==Dosages== |
| | For schizophrenia/psychosis in adults: |
| | *Oral: 0.5 - 5 mg 2 - 3 times daily, up to 30 mg/day for severe cases |
| | *IM (lactate): 2 - 5 mg every 4 - 8 hours as needed, max 20 mg/day |
| | *IM (decanoate):10 - 20 times daily oral dose given monthly |
| | |
| | ==Side Effects== |
| {| class="wikitable" | | {| class="wikitable" |
| !Generic Name 藥名 | | !style="text-align: left"| Frequency |
| !HA Code 藥物代碼 | | !Adverse reactions |
| !Classification藥物分類
| | |- |
| | | rowspan="9" | '''Common |
| | | Insomnia |
| | |- |
| | | Drowsiness and sedation |
| |- | | |- |
| |Haloperidol Tab 1 mg | | | Dizziness |
| |HALO14
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| |P1S1S3
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| |- | | |- |
| |Haloperidol Tab 1.5 mg | | | Dry mouth |
| |HALO03
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| |P1S1S3
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| |- | | |- |
| |Haloperidol Tab 5 mg | | | Blurred vision |
| |HALO05
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| |P1S1S3
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| |- | | |- |
| |Haloperiodl Drops 2mg/ml 30ml | | | Constipation |
| |HALO16
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| |P1S1S3
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| |- | | |- |
| |Haloperidol IM Injection 5mg/ml 1ml | | | Weight gain |
| |HALO08
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| |P1S1S3
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| |}
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| ==Mechanism of Action==
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| Haloperidol is a typical antipsychotic that blocks dopamine D2 receptor with high affinity.
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| The presumed effectiveness of antipsychotic drugs relied on their ability to block dopamine receptors. This assumption arose from the dopamine hypothesis that maintains that both schizophrenia and bipolar disorder are a result of excessive dopamine activity.
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| In addition, haloperidol also acts as an antagonist (blocking agent) on different postsynaptic and presynaptic receptors:
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| *Dopamine receptors (subtypes D1, D2, D3, D4 and D5), which account for its antipsychotic properties
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| *Serotonin receptors (5-HT2, 5-HT6 and 5-HT7), with anxiolytic, antidepressant, and anti-aggressive properties
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| *Histamine receptors (H1 receptors) accounting for sedation, antiemetic effect
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| *α1- and α2-adrenergic receptors accounting for lowering of blood pressure, reflex tachycardia, vertigo, sedation, hypersalivation and incontinence as well as sexual dysfunction
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| *M1 muscarinic acetylcholine receptors causing anticholinergic symptoms such as dry mouth, blurred vision, constipation, difficulty to urinate, sinus tachycardia, and loss of memory.
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| ==Dosage==
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| {| class="wikitable"
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| !style="text-align: left"| Indication
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| !style="text-align: left"| Dose
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| |- | | |- |
| !style="text-align: left"|
| | | Increased appetite |
| *Schizophrenia
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| *Psychoses
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| *Mania
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| |By ''mouth
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| ADULT:
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| *Initially 2 - 20 mg once daily, or
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| *Initially 2 – 20 mg in divided doses
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| *Maintenance 1 – 3 mg 3 times a day, adjusted according to response
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| ELDERLY or debilitated patients:
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| *Initially 1 – 10 mg once daily, or
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| *Initially 1 – 10 mg daily in divided doses;
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| *Maintenance 1 – 3 mg 3 times a day, adjusted according to response
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| *Maximum 20 mg per day
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| CHILD 3 to 12 years:
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| *Initially 500 micrograms daily
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| *Increased to a usual dose of 1 to 4 mg daily
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| *Maximum of 6 mg daily
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| CHILD 13 to 17 years:
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| *Initially 500 micrograms daily
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| *Increased to a usual dose of 1 to 6 mg daily
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| (Maximum of 10 mg daily
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| By ''intramuscular injection
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| ADULT:
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| *2 – 5 mg, repeated dose given according to response and tolerability.
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| ELDERLY or debilitated patients:
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| *1 – 2.5 mg, repeated dose given according to response and tolerability.
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| *Maximum 12 mg per day
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| |- | | |- |
| !style="text-align: left"| Agitation and restlessness in the elderly
| | | Urinary retention |
| |By ''mouth
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| ADULT:
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| *0.75 – 1.5 mg 2-3 times a day, adjusted according to response
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| |- | | |- |
| !style="text-align: left"|
| | | rowspan="9" | '''Serious |
| *Tourette syndrome
| | | Extrapyramidal symptoms (movement disorders): |
| *Severe tics
| | *Muscle stiffness or spasms |
| *Intractable hiccup
| | *Tremors |
| |By ''mouth
| | *Restlessness (akathisia) |
| ADULT:
| | *Parkinson-like symptoms |
| *1.5 – 3 mg 2 -3 times daily | |
| *Maintenance 0.5 – 3 mg 3 times daily | |
| ELDERLY or debilitated patients:
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| *0.75 – 1.5 mg 2-3 times daily | |
| *Maintenance 0.5 – 1 mg 3 times daily
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| |- | | |- |
| !style="text-align: left"| Nausea and vomiting of terminal illness
| | | Taradive dyskinesia (potentially irreversible involuntary movements of face and tongue) |
| |By ''mouth
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| ADULT:
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| *1.5 mg 1-2 times daily, increased to
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| *5 – 10 mg daily in divided doses if necessary
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| |}
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| During long-term treatment of chronic psychiatric disorders, the daily dose should be reduced to the lowest level needed for maintenance of remission. Doses of haloperidol greater than 5mg increased the risk of side effects without improving efficacy.
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| ==Side Effects==
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| Comparing to other typical antipsychotic, Haloperidol is less likely to cause sedation, hypotension, or antimuscarinic effects, but is associated with a higher incidence of movement disorder known as tardive dyskinesia which may be permanent.
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| Neuroleptic malignant syndrome and QY interval prolongation may occur.
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| In older people with psychosis due to dementia it results in an increased risk of death.
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| Possible side effects include:
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| {| class = "wikitable"
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| !style="text-align: left"| Common (>1% incidence)
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| !style="text-align: left"|
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| |- | | |- |
| !Extrapyramidal side effects including
| | | Neuroleptic malignant syndrome (fever, muscle rigidity, altered mental state) |
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| *Akathisia (motor restlessness)
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| *Dystonia (continuous spasms and muscle contractions)
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| *Muscle rigidity
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| *Parkinsonism
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| |- | | |- |
| !style="text-align: left"| Orthostatic Hypotension
| | | Low white blood cell count (agranulocytosis) |
| | | |
| |- | | |- |
| !style="text-align: left"| depression
| | | Seizures |
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| |- | | |- |
| !style="text-align: left"| Weight loss
| | | QT prolongation leading to dangerous heart arrhythmias |
| | | |
| |- | | |- |
| !style="text-align: left"| Anticholinergic side effects such as
| | | Hyperprolactinemia: |
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| | *Breast enlargement or milk production |
| *Dry mouth
| | *Menstrual changes |
| *Constipation
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| *Difficulty to urinate
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| *Blurred vision
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| *Mydriasis | |
| *Tachycardia | |
| |- | | |- |
| !style="text-align: left"| Rare (< 1% incidence)
| | | Hypersensitivity reactions |
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| *Bronchospasm
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| *Hypoglycemia
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| *Inappropriate antidiuretic hormone secretion
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| *Photosensitivity reactions
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| *pigmentation
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| |- | | |- |
| !style="text-align: left"|Frequency not known
| | | Inappropriate antidiuretic hormone secretion |
| |
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| *stevens- Johnson syndrome
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| *toxic epidermal necrolysis
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| *prolonged QT intervals
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| |} | | |} |
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| ==Pharmacokinetics== | | ==Pharmacokinetics== |
| {|class="wikitable"
| | *Metabolism: Hepatic |
| !style="text-align: left"| Oral bioavailability
| | *Elimination half-life: 14 to 26 hours (IV), 20.7 hours (IM), 14 to 37 hours (oral) |
| |Haloperidol is readily absorbed after oral doses.
| | *Excretion: Biliary and renal |
| |-
| | *Onset: 30 - 60 minutes (oral), rapid (IM/IV) |
| !style="text-align: left"| Onset of action
| | *Duration: 24 hours or longer |
| |There is wide intersubject variation in plasma concentrations of haloperidol. In practice, no strong correlation has been found between plasma concentrations of haloperidol and its therapeutic effect.
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| Peak plasma concentrations range from 1.7 to 6.1 hours after ingestion.
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| |-
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| !style="text-align: left"| Metabolism
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| |It is extensively metabolized in the liver via CYP-mediated oxidation, primarily by CYP3A4.
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| |-
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| !style="text-align: left"| Elimination half-life
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| It is excreted in the urine and faeces.
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| Owing to the first-pass metabolism in the liver, plasma concentrations after oral doses are much lower than those after intramuscular doses.
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| The plasma half-life of ranging from about 12 to 38 hours after oral dose.
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| Moreover, there is wide intersubject variation in plasma concentrations of haloperidol. In practice, no strong correlation has been found between plasma concentrations of haloperidol and its therapeutic effect.
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|
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| The decanoate ester of haloperidol is very slowly absorbed from the injection site and is therefore suitable for depot injection.
| | ==Drug Precautions== |
| The plasma concentrations reach a peak at about 6 days after the injection, falling thereafter, with an approximate half-life of 3 weeks.
| | '''Pregnancy |
| |}
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|
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| ==Drug Management==
| | Use only if potential benefits outweigh the risks. May cause extrapyramidal symptoms in newborns if used in the third trimester. |
| ===Monitoring:===
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| Baseline ECG required before treatment – assess need for further ECGs during treatment on an individual basis.
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| During long-term use, routine monitoring includes:
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| *measurement of BMI
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| *blood pressure
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| *fasting blood sugar and lipids
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|
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| ===Drug interaction===
| | '''Breastfeeding |
| The metabolism of haloperidol is mediated by the cytochrome P450 system, particularly the isoenzymes CYP3A4 and CYP2D6. Therefore, there is the potential for interactions between haloperidol and other drugs that induce, inhibit, or act as a substrate for these isoenzymes, resulting in altered plasma haloperidol concentrations. It may be necessary to amend the dosage of haloperidol when given with sch drugs. Haloperidol itself is also an inhibitor of CYP2D6 and may increase the plasma concentrations of tricyclic antidepressants by inhibiting their metabolism.
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| Haloperidol must be used with extreme caution in patients receiving lithium; an encephalopathic syndrome has been reported after their use together.
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| {| class="wikitable"
| | Use caution. Haloperidol is excreted in breast milk. |
| !Drugs given with haloperidol
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| !Potential Effect
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| |-
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| |style="text-align: left"|
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| *CNS-depressant drugs including alcohol, hypnotics, anxiolytics, and opioids.
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| Potentiates the sedative effect.
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| The doses of concomitantly used opioids for chronic pain can be reduced by 50%.
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| |-
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| |style="text-align: left"|
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| *Lithium
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| |An encephalopathic syndrome characterized by delirium, seizures, or an increased incidence of extrapyramidal symptom, and coma
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| |-
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| |style="text-align: left"|
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| *Tricyclic antidepressants
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| |Metabolism and elimination of tricyclics significantly decreased, increased toxicity such as anticholinergic and cardiovascular side effects, and lowering seizure threshold.
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| |-
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| |style="text-align: left"|
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| *Levodopa
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| |In theory, antipsychotics with dopamine-blocking activity and dopaminergic drugs such as those used to treat parkinsonism may be mutually antagonistic.
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| |-
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| |style="text-align: left"|
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| *Methyldopa
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| *Drugs metabolized by the CYP3A4 enzyme system: inducers such ass carbamazepine, phenobarbitone and rifampicin
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| *Increased risk of extrapyramidal side effects
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| *Decreases plasma levels of haloperidol
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| |-
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| |style="text-align: left"|
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| *Drugs metabolized by the CYP3A4 enzyme system: inhibitors such as quinidine, buspirone and fluoxetine
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| |Increases plasma levels of haloperidol
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| |-
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| |style="text-align: left"|
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| *Drugs that prolong the QT interval e.g. amiodarone
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| |An increased risk of ventricular arrhythmias – avoid concomitant use.
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| |}
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|
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| ===Caution===
| | '''Children and Elderly |
| *In patient with Alzheimer’s with mild behavioral problems, its use often make their condition worse and its withdrawal is even beneficial for some cognitive and functional measures.
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| *In patients with impaired liver, as haloperidol is metabolized mainly by the liver
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| *Patients at special risk for the development of QT prolongation (hypokalemia, concomitant use of other drugs causing QT prolongation)
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| *In those with thyrotoxicosis
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| *Patients with a history of leukopenia: a complete blood count should be monitored frequently during the first few months of therapy and discontinuation of haloperidol if white blood cells
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|
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| ===Contra-indications===
| | Use caution. Children may be more sensitive to side effects. Elderly patients may require lower doses and are at increased risk of adverse effects. |
| Use of chlorpromazine should be avoided in individuals with: | |
| *CNS depression
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| *Comatose states
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| *Acute stroke
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| *Parkinson’s disease
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| *Phaeochromocytoma
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| *QT-interval prolongation, when combined will tend towards cardiac arrest
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|
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| ===Hepatic impairment===
| | '''Monitoring Requirements |
| *Can precipitate coma. | | *Extrapyramidal symptoms |
| | *ECG in patients at risk of QT prolongation |
| | *Blood pressure |
| | *Complete blood count |
| | *Liver function tests |
|
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| ===Renal impairment===
| | '''Drug Interactions |
| *Start with small doses in severe impairment because of increased cerebral sensitivity. | | *Increased sedation with CNS depressants |
| | *Increased risk of arrhythmias with drugs that prolong QT interval |
| | *Reduced effectiveness of levodopa |
| | *Increased plasma levels with CYP3A4 inhibitors |
|
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| ===Pregnancy=== | | ==FAQ== |
| Should be avoided in pregnancy unless the physician considers it essential. | | '''How Should I Take the Tablet? |
|
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| ===Breast-feeding===
| | It can be taken with or without food. |
| Use during breast feeding is not recommended.
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|
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| ===Driving and skilled tasks===
| | '''What should I avoid while taking? |
| Drivers and machine operators should be told about the risk of drowsiness with this medication especially at the start of treatment. Affected patients should not drive or operate machinery.
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|
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| == FAQ ==
| | Avoid alcohol and activities requiring mental alertness until you know how haloperidol affects you. |
| ====What should I avoid while taking?====
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| Avoid drinking alcohol while taking haloperidol because it may enhance the side effects of sedation. | |
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| Avoid driving or hazardous activity until you know how chlorpromazine will affect you.
| | '''What Happens if I Miss a Dose? |
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| Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.
| | Take the missed dose as soon as you remember unless it is almost time for your next dose. Do not double doses. |
| ==== What happen if I overdose? ====
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| Contact your primary care doctor.
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| If emergency situation, call 999
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| ==== What happen if I miss a dose? ====
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| Take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
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