paliperidone palmitate (Invega Sustenna)

Invega Sustenna (paliperidone palmitate) is an atypical antipsychotic used to treat schizophrenia. It is a long acting form of paliperidone (Invega). Other atypical antipsychotic drugs include

• olanzapine (Zyprexa),
• quetiapine (Seroquel),
• ziprasidone (Geodon),
• iloperidone (Fanapt),
• asenapine (Saphris) and
• aripiprazole (Abilify).

Atypical antipsychotics differ from typical antipsychotics because they cause a lesser degree of movement (extrapyramidal) side effects and constipation.

The exact mechanism of action of paliperidone is not known, but, like other anti-psychotics, it is believed that paliperidone affects the way the brain works by interfering with communication among the brain's nerves. Nerves communicate with each other by making and releasing chemicals called neurotransmitters. The neurotransmitters travel to other nearby nerves where they attach to receptors on the nerves. The attachment of the neurotransmitters either stimulates or inhibits the function of the nearby nerves. Paliperidone blocks several of the receptors on nerves including dopamine type 2, serotonin type 2, and alpha 2 adrenergic receptors. It is believed that many psychotic illnesses are caused by abnormal communication among nerves in the brain and that by altering communication through neurotransmitters, paliperidone can alter the psychotic state. Invega Sustenna was approved by the FDA in July 2009.

What brand names are available for Invega Sustenna?

Invega Sustenna

Is Invega Sustenna available as a generic drug?

No

Do I need a prescription for Invega Sustenna?

Yes

The most common side effects include

• injection site reaction,
• weight gain,
• headache,
• upper respiratory tract infection,
• feeling restlessness or difficulty sitting still,
• stiffness and shuffling walk,
• tremors, and
• slow movements.

Less common but serious side effects include:

• Increased risk of stroke in elderly patients with dementia-related psychosis.
• Neuroleptic malignant syndrome (NMS). NMS is a rare but serious side effect associated with the use of antipsychotics. NMS may result in death and must be treated in the hospital. Signs and symptoms of NMS may include high fever, sweating (diaphoresis), severe muscle stiffness or rigidity, confusion, loss of consciousness, high blood pressure, rapid heartbeat, and changes in your breathing.
• Extrapyramidal side effects (EPS) include:
  • Dystonia: painful spasms of the oral, throat, or neck muscles that may cause problems with speech, swallowing, and stiff neck.
  • Akathisia: feelings of restlessness or difficulty sitting still.
  • Pseudoparkinsonism: drug-induced Parkinson's symptoms.
• Tardive dyskinesia (TD). TD usually occurs after long term use of antipsychotics and usually causes movement problems affecting the tongue, lips, jaw, face, and extremities.
• Metabolic changes including high blood sugar (hyperglycemia), diabetes mellitus, increase in blood cholesterol, and weight gain.
• High blood levels of prolactin. Prolactin is a hormone that allows the production of breast milk. High levels of prolactin may cause menstrual abnormalities, leakage of milk from the breast, development of breasts in (males gynecomastia), and erection problems in men (erectile dysfunction).
• Seizures

Invega Sustenna is administered once every month by a health-care professional. Invega Sustenna is injected intramuscularly (into the muscle) in the upper arm or upper buttocks.

The starting dose for schizophrenia or schizoaffective disorder is 234 mg on day one then 156 mg one week later (day 8) injected into the upper arm. The monthly maintenance dose is 39 to 234 mg for schizophrenia and 78 to 234 mg for schizoaffective disorder. Maintenance injections may be administered into the upper arm or buttocks. The maximum dose is 234 mg monthly.

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Invega Sustenna can cause low blood pressure especially when standing up from sitting or lying down (orthostatic hypotension). Therefore, Invega Sustenna should be used cautiously with other drugs also associated with orthostatic hypotension.

Paliperidone is metabolized or broken down by liver enzymes. Drugs that induce these enzymes will increase their activity and consequently decrease blood levels of paliperidone. Invega Sustenna should not be taken with carbamazepine (Tegretol), phenytoin (Dilantin), rifampin (Rifadin), St. John's Wort, and other drugs that may decrease its blood levels.

Paliperidone blocks the effect of dopamine in the brain while dopamine agonists such as levodopa (Sinemet) increase the levels of dopamine in the brain. Combining these agents is not recommended since the effect of both drugs will be reduced.

Invega Sustenna is known to enter human milk but its effects on the breastfeeding infant or milk production is not yet known.

What preparations of Invega Sustenna are available?

Extended-release injectable suspension: 39, 78, 117, 156, or 234 mg

How should I keep Invega Sustenna stored?

Invega Sustenna should be stored at room temperature between 59 F and 86 F (15 C to 30 C).