Imipramine

Antidepressant Drug

Drug class: Tricyclic Antiperessant Drug

Imipramine (TOFRANIL)（中文：米帕明）

Common Strengths of Imipramine

Imipramine are available in the following strengths:

• Tablets: 10 mg, 25 mg, 50 mg
• Capsules: 75 mg, 100 mg, 125 mg, 150 mg

Drug Trade Names of Imipramine

• Tofranil
• Tofranil-PM

Drug Usage

• Primary use: Treatment of depression
• Other uses: Anxiety disorders, panic disorder, chronic pain, enuresis (bed-wetting) in children

Mechanism of Action

Imipramine works by inhibiting the reuptake of serotonin and norepinephrine in the brain, with a stronger effect on serotonin. This increases the levels of these neurotransmitters, which help regulate mood.

Route of Administration

Oral (tablets and capsules)

Dosages

For depression in adults:

• For depression: Initial dose 75 mg/day, may increase to 150 mg/day. Maximum 200 mg/day.
• Maintenance dose: 50-100 mg/day.

Side Effects

Frequency	Adverse reactions
Common	These side effects are typically mild and may lessen as the body adjusts to the medication.
	Dry mouth
	Drowsiness or sedation
	Nausea and vomiting
	Constipation
	Increased blood pressure
	Tremors
	Weight gain
	Difficulty urinating
Serious	Suicidal Thoughts: There is an increased risk of suicidal thoughts and behaviors, especially in children, teenagers, and young adults under 24 years old. Patients should be monitored closely for mood changes, anxiety, or agitation.
	Cardiovascular Issues: Serious complications can include irregular heartbeats and chest pain
	Seizures: May lower the seizure threshold, leading to seizures, particularly in individuals with a history of seizure disorders.
	Serotonin Syndrome: When taken with other serotonergic medications (e.g. SSRIs), imipramine can cause serotonin syndrome, a potentially life-threatening condition characterized by agitation, hallucinations, rapid heart rate, muscle rigidity, and gastrointestinal symptoms.
	Eye Problems: Symptoms may include blurred vision, eye pain, or swelling, which can indicate increased intraocular pressure or angle-closure glaucoma.
	Jaundice: Yellowing of the skin or eyes may indicate liver dysfunction and requires immediate medical attention.
	Allergic Reactions: Signs include hives, difficulty breathing, and swelling of the face or throat, which necessitate emergency medical help.

Pharmacokinetics

• Absorption: Rapidly absorbed from the gastrointestinal tract
• Metabolism: Primarily in the liver via CYP2D6
• Elimination: Mainly excreted in urine, with a half-life of 19 to 37 hours
• Drug Onset time: 2 to 3 weeks for full effect in depression

Drug Precautions

Pregnancy

Use only if needed; potential risks to the fetus

Breastfeeding

Excreted in breast milk; use with caution

Children and Elderly

Not recommended for children under 6 years; lower doses for elderly

Monitoring Requirements

Blood pressure, heart rate, mental status, suicidal thoughts

Drug Interactions

• Serotonergic Drugs: Combining imipramine with other serotonergic medications (e.g. lithium, tramadol, St. John's Wort) increases the risk of serotonin syndrome.
• Central Nervous System (CNS) Depressants: Taking imipramine with other CNS depressants like benzodiazepines or alcohol can enhance sedation and increase the risk of respiratory depression.
• Thyroid Medications: Imipramine may interact with thyroid drugs (e.g. levothyroxine), potentially leading to cardiovascular issues like rapid heart rate.
• Warfarin: Imipramine may increase the risk of bleeding when taken with anticoagulants like warfarin.
• Digoxin: Imipramine can increase the risk of digoxin toxicity, leading to symptoms like confusion and irregular heartbeats.
• Anticholinergic drugs

FAQ

How Should I Take the Tablet?

Usually with food to reduce stomach upset. Often taken at bedtime due to sedating effects.

What Should I Avoid While Taking?

Avoid alcohol, driving or operating machinery until you know how the medication affects you.

What Happens if I Miss a Dose?

Take it as soon as you remember, unless it is almost time for your next dose. Never take a double dose to make up for a missed one.