Pamelor

General information

Pamelor is a drug belonging to the group of tricyclic antidepressants. The drug is used mainly for treatment of depressive states of various etiologies, as well as for relief of symptoms of some neurological and psychiatric disorders. Its action is based on the effect on neurotransmitters in the brain, which helps to stabilize mood and reduce the severity of psychoemotional disorders.

Trade name

Pamelor

International Nonproprietary Name (INN)

Nortriptyline

Form of release

The drug is available in the following forms:

• Capsules for oral administration: dosages of 10 mg, 25 mg, 50 mg and 75 mg.
• Solution for oral administration: concentration of 10 mg/5 ml, available in 473 ml vials.

Composition

Acting substance

Nortriptyline (in the form of hydrochloride).

Auxiliary components

The composition varies depending on the form of release:

• Capsules: lactose monohydrate, corn starch, magnesium stearate, gelatin (capsule shell), titanium dioxide (as a coloring agent).
• Solution: purified water, sorbitol, citric acid, sodium benzoate (preservative), flavoring.

Pharmacological properties

Pharmacodynamics

Nortriptyline, the active ingredient in Pamelor, is a second-generation tricyclic antidepressant. Its mechanism of action is to inhibit the reuptake of neurotransmitters - norepinephrine and serotonin - in the synaptic cleft of neurons of the central nervous system. This leads to an increase in the concentration of these mediators in the intercellular space, which helps to improve the transmission of nerve impulses and normalize mood. The drug has a moderate anticholinergic effect, which may manifest itself in the form of adverse reactions, such as dry mouth or urinary retention. It also has a mild sedative effect through blockade of histamine H1 receptors, which may be useful in depression accompanied by insomnia.

Nortriptyline also shows some activity against alpha-adrenoreceptors, which may affect vascular tone and blood pressure. Its therapeutic effects are usually apparent after 1-3 weeks of regular use, although some patients report feeling better sooner.

Pharmacokinetics

After oral administration, nortriptyline is well absorbed from the gastrointestinal tract, reaching maximum plasma concentrations after 4-8 hours. Bioavailability is about 50-60% due to the effect of first passage through the liver. Binding to blood plasma proteins (mainly albumin) reaches 90-95%, which ensures prolonged presence of the drug in the body.

Metabolism of nortriptyline occurs in the liver with the participation of enzymes of the cytochrome P450 system, mainly CYP2D6. The main metabolite, 10-hydroxynortriptyline, has pharmacologic activity, although its contribution to the overall effect of the drug is insignificant. The elimination half-life varies from 16 to 90 hours (26 hours on average), which depends on individual metabolic peculiarities of the patient.

Extraction is carried out mainly by the kidneys (about 70% in the form of metabolites) and partially through the intestine with bile. In patients with impaired hepatic or renal function, metabolism and excretion may be slowed down, which requires dosage adjustment.

Indications for use

Pamelor is prescribed for the following conditions:

• Moderate to severe depressive disorders, including endogenous and reactive depression.
• Depression accompanied by anxiety or insomnia.
• Chronic pain syndromes (e.g., neuropathic pain), as adjunctive therapy.
• Migraine prophylaxis (in some cases, as prescribed by a physician).

Contraindications

The use of Pamelor is prohibited under the following conditions:

• Hypersensitivity to nortriptyline or any of the excipients of the drug.
• Recently suffered myocardial infarction (within the last 3 months).
• Severe cardiac conduction disorders (atrioventricular block of II-III degree, complete Gis bundle block).
• Simultaneous use of monoamine oxidase inhibitors (MAOIs) or a period of less than 14 days after their withdrawal.
• Closed-angle glaucoma.
• Severe hepatic or renal impairment.
• Children under 6 years of age (for solution) or under 12 years of age (for capsules).

Method of administration and dosage

How to take

The drug is taken orally, regardless of food intake. Capsules should be swallowed whole, drinking enough water (at least 100 ml). The solution is measured with the provided measuring spoon or syringe and can be mixed with water or juice (but not with milk or carbonated drinks).

Dosages for adults and children

Adults

The starting dose is 25 mg 1 to 3 times daily. If necessary, the dose is gradually increased by 25 mg every 3-7 days until the therapeutic effect is achieved (usually 75-150 mg per day). The maximum daily dose is 150 mg.

Children (6-12 years, solution only)

Dosage is calculated individually: 0.1-0.5 mg/kg body weight per day, divided into 2-3 doses. The maximum daily dose is 30 mg.

Adolescents (12-18 years old)

The initial dose - 10-25 mg per day, with possible increase up to 50-100 mg per day under the supervision of a doctor.

Dose adjustment for certain conditions

In renal or hepatic impairment, the initial dose is reduced to 10 mg per day, followed by a slow increase under medical supervision. In elderly patients (over 65 years of age) it is recommended to start with 10-25 mg per day, not exceeding 100 mg per day.

Side Effects

The following adverse reactions are possible with Pamelor:

• Side of the nervous system: drowsiness, dizziness, headache, headache, tremor, confusion.
• Cardiovascular system: tachycardia, orthostatic hypotension, arrhythmias.
• Digestive system: dry mouth, nausea, constipation, increased appetite.
• Side of the genitourinary system: urinary retention, decreased libido.
• Allergic reactions: skin rash, itching, angioedema (rare).
• Other: increase in body weight, increased fatigue, sweating.

Overdose

Symptoms of overdose

If the recommended dose is exceeded, the following may be observed:

• Significant drowsiness or coma.
• Convulsions.
• Tachycardia or bradycardia, decreased blood pressure.
• Difficulty breathing.
• Hallucinations, confusion.

First aid measures

In case of suspected overdose it is necessary:

1. Stop taking the drug.
2. Call an ambulance.
3. Rinse the stomach (if it has been less than 1 hour since the intake).
4. Give activated charcoal (1 g/kg body weight).
5. Ensure control of respiration and cardiac activity until the arrival of a doctor.

Interaction with other drugs

Influence on the effects of other drugs

Pamelor may increase the effects of the following drugs:

• Sedatives and sleeping pills.
• Antihypertensive agents (excessive hypotension may occur).
• Anticoagulants (increased risk of bleeding).

The drug reduces the effectiveness of sympathomimetics (e.g., adrenaline).

Compatibility with alcohol and food

Simultaneous use of alcohol increases the sedative effect and increases the risk of overdose, especially in depressed patients. Food does not significantly affect the absorption of the drug.

Special instructions

Use in pregnancy and breastfeeding

The use of Pamelor during pregnancy is acceptable only under strict indications if the benefit to the mother exceeds the risk to the fetus. Nortriptyline penetrates the placental barrier and may cause fetal abnormalities. In breastfeeding the drug is contraindicated, as it is excreted with breast milk and may adversely affect the child.

Effects on driving and mechanisms

The drug may cause drowsiness and decreased concentration, especially at the beginning of therapy. Patients are advised to refrain from driving and working with dangerous mechanisms until assessment of individual response to treatment.

Particularities of use in the elderly and children

In elderly patients anticholinergic side effects (confusion, urinary retention) occur more often, therefore careful dose selection is required. In children the drug is used with caution, only when prescribed by a doctor, taking into account body weight and age.