Invega

Invega is an antipsychotic medication.

[ 1 ]

Indications Invega

It is used to treat schizophrenia in adolescents from 15 years of age, and also in adults. It is also prescribed to adults in the treatment of schizoaffective disorders.

Release form

Released in tablets, 7 pieces inside a blister pack. In a pack - 4 blisters with tablets.

Pharmacodynamics

The medicine contains a racemic mixture of the substance paliperidone.

Paliperidone is a selective blocking agent with monoamine action. Its medicinal effect is different from standard neuroleptics. The substance is tightly synthesized with serotonin receptors (type 5-HT2), as well as dopamine (D2). At the same time, it acts as an antagonist of α1-adrenoreceptors, as well as histamine receptors (H1) and α2-adrenoreceptors (it acts less actively towards the latter two). The medicinal activity of (+) and (-)-enantiomers of the active substance is similar both in quantity and in the degree of action.

Paliperidone is not synthesized with acetylcholine receptors. Although the substance acts as a powerful antagonist of D2 conductors, which suggests a decrease in the positive signs of schizophrenia, it contributes to the development of catalepsy, as well as weakening of motor effects not as much as standard neuroleptics. Since the drug has a predominantly central antagonism of serotonin, this can weaken the property of the active component to cause side effects of extrapyramidal etiology.

[ 2 ]

Pharmacokinetics

The pharmacokinetics of the drug is proportional to the dosage size within the available range.

When using a single dose of the drug, a gradual increase in its release rate is observed, due to which the plasma indicator of paliperidone steadily increases. Peak values of the drug are noted after 24 hours. Many patients have stable indicators of the substance after 4-5 days of daily single intake of tablets.

Paliperidone is the active breakdown product of risperidone. The release profile of Invega is the result of a weak peak fluctuation compared to that found with immediate release risperidone (fluctuation index of 38% compared to 12.5%).

Bioavailability indicators of the drug when taken orally reach 28%.

When tablets are taken in combination with high-calorie or fatty foods, peak values and AUC levels of paliperidone increase by 50-60% compared to taking the drug on an empty stomach.

The drug undergoes rapid distribution within fluids with tissues. The distribution volume is 487 liters. The degree of protein binding within plasma reaches 74%. The substance is synthesized mainly with albumins, as well as with α1-acid glycoprotein.

Following a single dose of 1 mg of 14C-labeled paliperidone, 59% of the dose is excreted after 7 days, with unchanged drug excreted in the urine. This demonstrates that the drug is not extensively metabolized by the liver. Approximately 80% of the labeled drug is found in the urine, and approximately 11% is found in the faeces.

Dosing and administration

For adults with schizophrenia.

It is recommended to take the drug in the amount of 6 mg once a day (taken in the morning). There is no need to titrate the dose at the initial stage of treatment. In some patients, the medicinal effect of the drug is observed when taking the smallest or largest dose (within the range that is allowed for use - 3-12 mg once a day). Changing the dose is allowed if there are such indications, as well as after a careful re-evaluation of the health condition. If it is necessary to increase the portion, this increase should be carried out according to the following scheme: 3 mg / day with breaks of at least 5 days.

For adults with schizoaffective disorders.

It is necessary to take the medicine in the morning in the amount of 6 mg once a day. In some patients, therapeutic effectiveness develops after using a large dosage (within the permitted range - 6-12 mg once a day). If it is necessary to increase the dose, it is necessary to increase it by adding 3 mg / day with intervals of at least 4 days.

People with functional renal impairment.

Individuals with a mild form of the disease (CC level ≥50/<80 ml/min) should take the drug once a day at a dose of 3 mg. It is allowed to increase the dose to 1-time intake of 6 mg per day, but only after assessing the patient's tolerability of the drug, as well as its medicinal efficacy.

People with moderate or severe forms of the disorder (CC ≥10/<50 ml/min) should take the medicine in the amount of 1.5 mg, once a day. The portions may be increased to 1-time intake of no more than 3 mg per day after a clinical assessment of the health condition.

The use of Invega in individuals with a CrCl level <10 ml/min has not been conducted, therefore it is not recommended to prescribe the drug to this group of patients.

For children with schizophrenia.

Adolescents over 15 years of age are initially recommended to take the medicine in a dosage of 3 mg - a single dose in the morning.

Children weighing <51 kg can take no more than 6 mg of the drug per day.

Children weighing ≥51 kg can take a maximum of 12 mg of the drug per day.

The dose can be changed if there are appropriate indications. The increase should be performed according to the following scheme: by 3 mg per day with intervals of at least 5 days.

The efficacy and safety of the drug in the treatment of schizophrenia in adolescents aged 12-14 years have not been studied.

The medicine is taken orally - by swallowing the tablet whole, without chewing or crushing, and also washed down with water. The tablet shell is insoluble, and the active component is gradually released from under it. The shell, together with the insoluble elements of the core, is completely excreted from the body.

The use of the drug depends on the consumption of food. It is necessary to tell the patient that the tablets should be taken constantly either on an empty stomach or with breakfast, without alternating these methods of administration during the treatment period.

Use Invega during pregnancy

There are insufficient data on the use of paliperidone in pregnancy. The substance has not been shown to be teratogenic in animal tests, but other types of reproductive toxicity have been noted.

The use of antipsychotic drugs (including paliperidone) in the 3rd trimester increases the likelihood of adverse effects, including extrapyramidal manifestations or withdrawal syndrome in newborns. These symptoms may vary in duration and severity. There is information about the development of hyper- and hypotension, agitation, drowsiness and tremor, as well as respiratory failure and problems with feeding the baby. Because of this, the condition of newborns should be constantly and very carefully monitored.

The drug should not be prescribed to pregnant women (except for special vital indications). If it is necessary to stop taking Invega during pregnancy, the drug should be discontinued gradually.

Paliperidone passes into breast milk, so an effect of the drug on a breast-fed infant can be expected. Therefore, the drug is prohibited for use during lactation.

Contraindications

Main contraindications: hypersensitivity to paliperidone, risperidone, and any other additional components of the drug. It is prohibited to prescribe to children under 15 years of age.

[ 3 ]

Side effects Invega

The most common side effects that develop are:

• nasopharyngitis;
• a state of mania or insomnia;
• weight gain;
• headaches or muscle pain;
• abdominal discomfort, nausea, constipation or diarrhea, and increased appetite;
• dysarthria or akathisia;
• increased muscle tone, and also shaking palsy;
• feeling of drowsiness;
• hypersalivation.

Adverse reactions that occur less frequently:

• cystitis;
• ear infections, tonsillitis with bronchitis, and sinusitis;
• anaphylactic symptoms;
• leuko- or neutropenia, as well as anemia;
• hyperprolactinemia;
• hyper- or hypoglycemia, and in addition anorexia;
• development of diabetes mellitus;
• sleep disorders, nightmares;
• problems with concentration, the appearance of paresthesia or seizures, as well as psychomotor hyperactivity;
• dryness of the mucous membranes of the eyes, conjunctivitis, and lacrimation;
• ear ringing or pain;
• increase or decrease in blood pressure, bradycardia, prolongation of the QT interval, AV block;
• fecal incontinence, bloating, and gastroenteritis;
• swelling and stiffness in the joints, as well as arthralgia;
• urinary incontinence or dysuria;
• the appearance of discharge from the nipples, weakening of libido and the development of gynecomastia;
• problems with sexual function, menstrual cycle disorders;
• sensation of thirst, hypothermia, peripheral edema and a feverish state.

[ 4 ]

Overdose

In general, symptoms of drug intoxication are expected to manifest themselves in the form of potentiation of the drug's effects. These symptoms include sedation, drowsiness, decreased blood pressure, tachycardia, extrapyramidal symptoms, and prolongation of the QT interval. Bidirectional ventricular tachycardia and ventricular fibrillation have also been observed following poisoning.

When assessing the patient's condition, it is important to remember that the drug has a prolonged effect. It also has no specific antidote. General supportive procedures must be performed. It is necessary to ensure patency of the respiratory tract and adequate ventilation with oxygenation, and to maintain these functions. It is also necessary to constantly monitor the work of the cardiovascular system (this includes the ECG procedure) to determine the possible presence of arrhythmia. A decrease in pressure along with circulatory collapse is treated with intravenous injections of fluid or sympathomimetics. Sometimes gastric lavage (if the victim is unconscious, after the intubation procedure), administration of activated charcoal and laxatives may be required. In case of development of extrapyramidal disorders to a severe degree, it is necessary to administer anticholinergic drugs. Constant observation of the victim, as well as monitoring of vital physiological functions, must be performed until all manifestations of the overdose disappear.

[ 5 ], [ 6 ], [ 7 ]

Interactions with other drugs

The drug should be prescribed with caution with drugs that prolong the QT interval.

The active component of the drug does not cause significant drug interactions with drugs that are metabolized by the hemoprotein P450 system. In vitro tests showed that paliperidone does not have a suppressive or inducing effect on the isoenzymes of this hemoprotein.

Caution is required when combining with other drugs that have a central effect.

It is prohibited to combine with drugs that cause orthostatic hypotension.

Invega neutralizes the effects of levodopa.

The likelihood of drug interaction with lithium is very low.

When combined with sodium valproate, there were no changes in the concentrations of either drug. No significant drug interactions with paroxetine were detected.

Combined use with carbamazepine resulted in a 37% decrease in paliperidone levels in the blood. This requires adjustment of the dose of Invega with this combination.

Concomitant administration with trimethoprim did not affect the pharmacokinetics of the drug.

[ 8 ]

Storage conditions

Invega should be kept out of the reach of small children. The temperature should not rise above 30°C.

[ 9 ], [ 10 ]

Special instructions

Reviews

Invega effectively combats productive manifestations of schizophrenia (such as agitation with hallucinations, as well as delirium). Psychiatrists note that the drug is most effective in treating schizophrenia, against the background of which there is an apathetic-abulic syndrome (with such signs as indifference and apathy, as well as pathological weakness of will, a feeling of detachment and lack of desire to do anything). The use of the drug has a resocializing effect - the feeling of apathy towards what is happening around disappears, and a desire to act arises.

Patient reviews show that the drug, in addition to being highly effective, has a considerable number of side effects.

Invega is considered a safer drug compared to the substance risperidone, but it should be taken into account that it can only be prescribed to teenagers and adults.

[ 11 ]

Shelf life

Invega can be used for a period of 2 years from the date of manufacture of the drug.

[ 12 ], [ 13 ]