Short-Term Effects of Invega Oral Tablets
The oral tablets are designed to be slowly released after swallowing with liquid, and it is clearly stated on the drug label that the tablets should not be chewed, crushed or otherwise divided. The intended sustained-release effect will be lost, and other complications can occur.
The clinical trials before marketing Invega were short-term, and the side effects noted on the FDA drug labels for these medications is quite an extensive list. 3-5,7,12,13
Short-term side effects of Invega can include:
- Anaphylactic reactions: anxiety, abdominal pain, confusion, coughing, rash, trouble breathing, visible facial swelling
- Angioedema (swelling deep under the skin, or under mucous, genital, mouth, or sinus areas)
- NMS (neurologic malignant syndrome) a potentially fatal reaction to medication (see section below for a more detailed description)
- Extrapyramidal (involuntary muscle movement disorders) such as tardive dyskinesia, parkinsonism, dystonia, a twisting or unnatural body posturing, neck or other muscle spasms, tightening of the throat, protrusion of the tongue, difficulty breathing, etc. )
Fatigue, muscle weakness- Akathisia
- Anxiety
- Dizziness
- Headache
- Lethargy
- Somnolence, sedation
- Elevated prolactin causing enlarged male breasts, menstruation irregularity, other sexual dysfunction
- Cardiac disorders such as prolonged QT interval, tachycardia, blockages, stroke
- Increased cholesterol
- Gastrointestinal dysfunction, i.e., abdominal pain, nausea, hyper-salivation, dry mouth
- Weight gain
Long-Term Effects of Invega
Long-term effects of Invega include everything on the above list. There are some particularly concerning long-term effects associated with paliperidone, and these will be discussed in more detail below.3,5,12,13
Tardive Dyskinesia
Notably, the risks of extrapyramidal disorders such as tardive dyskinesia become elevated the longer the medication is used, and the higher the dose that was prescribed. Tardive dyskinesia is a drug-induced, typically chronic, disability. The person may experience a gradual onset of involuntary muscle movement such as grimacing, lip smacking , protrusion of the tongue, or other repetitive involuntary mouth movements. Torso, foot, jaw, may all be affected such as twisting or writhing movements. It is theorized that these repetitive and irregular movements are associated with irregularities or disruptions in dopamine or other hormonal expression. Over time the movement disorder may continue to worsen, even after the drug is withdrawn. It is estimated that about 20% of patients on older antidepressants such as Haldol, and 10% on the atypical antipsychotics such as Invega, will develop tardive dyskinesia over time.9
NMS Symptoms and Diagnosis Criteria of NMS
NMS stands for “neuroleptic malignant syndrome.” Neuroleptic is a word that stands for any antipsychotic medication. Anyone taking an antipsychotic medication, including Invega, should be aware of signs and symptoms of NMS as this can be life-threatening when it occurs.6
Signs and symptoms for a diagnosis of NMS include these:
- Exposure to a dopamine-blocking drug
- Hyperpyrexia, a life-threatening elevation of body temperature above 106.7 deg.
- Severe muscle rigidity
Two of the following symptoms and signs must also be present for a valid NMS diagnosis:
Excessive sweating(di-aphoresis)- Inability to swallow (dysphagia)
- Tremor
- Cannot speak, mutism
- Elevated heart rate, tachycardia
- Incontinence
- Altered mental state, unconsciousness
- Elevated blood pressure
- Changing blood pressure (labile, erratic)
- Higher than normal white blood count (leukocytosis)
- Elevated creatine phosphokinase, an enzyme that can indicate muscle injury
Suppression of Immune System
There has been inadequate research on how antipsychotic drugs affect the human immune system, especially over time.
In a trial on healthy mice, it was found that risperidone did lower the immune systems of the animals in the trial after only 5 days of exposure to the drug. These effects worsened by the end of the extended 4-week long study. This is an important area to research, and is a complex one.
In humans, the immune system is a key factor in staying healthy and the suppression of the immune system can lead to increased frequency or intensity of inflammation, infections, pneumonia, and similar risks.16
Motor and Cognitive Impairments
Motor and cognitive impairment risks are associated with all antipsychotic medications. This type of effect includes a number of signs and symptoms that are sometimes referred to as “parkinsonism.” In parkinsonism there can be a shuffling type of gait, difficulty in speaking or articulation words and speech.14
Anhedonia is another important symptom of long-term use of Invega. Anhedonia means a flattening of emotional response, loss of joy, drive, and motivation and these can occur with Invega and any of the other antipsychotics in general use today.
Are There Methods to Safely Taper Off a Drug like Invega?
As mentioned earlier, Invega either in the oral tablet form, or the injectable form, are designed to be released into the body slowly over time. The tablets cannot be cut or crushed, and the injectable form of Invega requires its own methods that would allow for safe reduction.
And safe tapering off a neuroleptic must be done extremely slowly. To go too fast is to invite potential catastrophic withdrawal phenomena. Antipsychotics dampen or block the expression of dopamine and other natural neurotransmitters. So, in tapering, you want to avoid a flood of these into the system, which could be extremely stimulating and may induce what is known as withdrawal-induced psychosis.11
So to taper off a drug such as Invega, one strategy that could be workable is to first convert to an equivalent dose of a drug that can be more easily gradually tapered, and transitioning to a drug such as Risperdal or similar may offer such a workable strategy. One would need to seek help from a prescriber who is familiar with these modes of withdrawal, familiar with antipsychotic withdrawal done safely and gradually, and who is sympathetic to your health goals.
There is an important black box warning on the packaging of Invega, which warns that there is an increased risk of death for elderly dementia patients who take this medication. This black box warning appears on all antipsychotic medications. In studies and over time it has been found that in general, people taking antipsychotic medications die earlier on average compared to persons who don’t take antipsychotic medications.1-5
