Aripiprazole

Aripiprazole (中文:[[ ]]) is an atypical antipsychotic or 2nd Generation antipsychotic medication. It is mainly used in the treatment of

• Schizophrenia: there is little difference in effectiveness between antipsychotics in prevention of relapse, the specific choice of antipsychotic be chosen based on person’s preference and side-effect profile.
• bipolar disorder: aripiprazole is effective for the treatment of acute manic episodes of bipolar disorder.It is useful for the prevention of manic episodes, but is not useful for bipolar depression.
• adjuinct treatment of major depressive disoreder

Aripiprazole rebalances dopamine and serotonin to improve thinking, mood and behaviour.

Drug Names

Generic Name 藥名	HA Code 藥物代碼	Classification藥物分類
Aripiprazole Tab 5 mg	ARIP03	P1S1S3
Aripiprazole Tab 10 mg	ARIP01	P1S1S3
Aripiprazole Tab 15 mg	ARIP02	P1S1S3

Mechanism of Action

Aripiprazole is a dopamine D2 partial agonist. It is also a partial activator of serotonin 5-HT1A receptors. Aripiprazole acts by modulating neurotransmission overactivity of dopamine, which is thought to mitigate schizophrenia symptoms.

Dosage

Indication	Dose
Schizophrenia	By mouth ADULT: 10 – 15 mg once daily, Maximum 30 mg once daily
Treatment and recurrence prevention of mania	By mouth ADULT: 15 mg once daily Maximum 30 mg once daily
Adjunct treatment of major depressive disorder	By mouth ADULT: Initially 2- 5 mg once daily, Increased to 5 – 10 mg once daily Maximum 15 mg once daily

How long does it take for Amisulpride to work? The patient may start to feel better in a few days but it can take as long as 4 to 6 weeks before the full effects of this medication is noticed.

Side Effects

All side-effects are listed by system organ and frequency.

• Common ( ≥ 1/100 to < 1/10)
• Uncommon (≥ 1/1000 to < 1/100)

Endocrine disorders	Uncommon: hyperprolactinaemia (elevated levels of the hormone prolactin, which for females may result in Galactorrhea (unwanted breast milk) amornorrhea (missed/stopped periods), For males it may result in decreased sexual ability, or gynecomastia (enlarged breast)
Muscle/Nervous system disorders:	Common: Extrapyramidal symptoms (EPS) -Tremor -Akathisia -Parkinsonism Anticholinergic side-effects such as: -Dry mouth -Constipation -Blurred vision headache sedation somnolence dizziness salivary hypersecretion Uncommon: tardive dyskinesia and seizures Not known: Neuroleptic malignant syndrome
Psychiatric disorders	Common: Insomnia Anxiety Restlessness Uncommon: Depression hypersexuality
Metabolism disorders	Common: diabetes mellitus weight gain Uncommon: Hyponatraemia Anorexia
Cardiac disorders	Uncommon: tachycardia orthostatic hypotension

Pathological gambling, compulsive shopping and binge eating can occur in patients treated with aripiprazole.

It is not recommended for older people with dementia-related psychosis due to an increased risk of death. Discontinuation

It is recommended that gradual withdrawal when discontinuing antipsychotics. Symptoms of withdrawal commonly include nausea, vomiting and loss of appetite. Symptoms generally resolve after a short period of time.

Pharmacokinetics

Oral bioavailability	It is readily absorbed after oral doses.
Onset of action	Peak plasma concentrations are achieved 3 – 5 hours after an oral dose.
Metabolism	It is metabolized in the liver, principally by the enzymes CYP2D6 and CYP3A4
Elimination half-life	It is eliminated via urine and faeces. The elimination half-life is approximately 75 hours. Steady-state plasma concentrations are achieved in about 14 days.