Tricyclic antidepressants

What are tricyclic antidepressants?

Tricyclic antidepressants, such as amitriptyline and nortriptyline, were once widely used as antidepressants before being replaced by newer antidepressant medications with better side effect profiles. Other uses for tricyclic antidepressants include treating insomnia, bed-wetting, and chronic pain syndromes such as fibromyalgia.

Tricyclic antidepressants are finding a place in the treatment of chronic pain and itching associated with some dermatological conditions.

What are tricyclic antidepressants used for?

Tricyclic antidepressants are helpful in reducing the symptoms of chronic pain in the following skin conditions:

• Vulvodynia (vulvar pain)

  • Vestibulodynia (pain with sexual intercourse)

  • Diesthetic vulvodynia (neuropathic pain)

• Herpes zoster and posherpetic herpes neuralgia

• Trophic trigeminal syndrome

Pain arising from these conditions is defined as sympathetically maintained pain (SMP). The pain is generally described as a burning sensation and is often in response to stimuli that normally do not cause pain. This pain originates from the nervous system. Amitriptyline appears to be effective in reducing this type of neuropathic pain at lower doses than those used to treat depression.

Tricyclic medications can reduce chronic pain ulcers even:

• Pyoderma gangrenous
• Polyarteritis nodosa
• Venous ulceration

• Epidermolysis bullosa.

Tricyclic antidepressants are sometimes prescribed successfully for pruritus (itching), especially when this is of neuropathic origin:

• Notalgia paraesthetica
• Brachioradial itch
• Vulvar itching
• Male genitalia dysesthesia

Tricyclic medication has some antihistamine H₁ blocking activity and may be helpful in treating urticaria even when conventional antihistamines have failed.

The dose of tricyclic drugs.

Typically, patients start tricyclic medications at a low dose of 5 to 10 mg daily, taken in the evening to minimize side effects. This is gradually increased to a maximum daily dose of 50-150 mg, depending on the response and tolerability of side effects by the patient. Patients should be advised that pain / itching relief is not immediate as it may take several weeks for the medication to be fully effective.

Side Effects of Tricyclic Medications.

Side effects of amitriptyline and nortriptyline include:

• Sedation
• Drowsiness
• Dry mouth (which could contribute to tooth decay)
• Blurry vision
• Constipation
• Increased sweating (hyperhidrosis)
• Difficulty urinating
• Dizziness due to a drop in blood pressure when standing up (postural hypotension)
• Nausea, confusion, or headache due to hyponatremia (sodium imbalance)
• Weight gain
• Heart rhythm disorders.

Anticholinergic / antimuscarinic side effects can occur in up to 50% of patients and elderly patients are at increased risk. Intolerance to these effects often leads to drug discontinuation. Other tricyclic antidepressants such as desipramine and nortriptyline can be better tolerated than amitriptyline.

It can be dangerous to take a tricyclic medicine with a monoamine oxidase inhibitor antidepressant (MAOI) medicine or within 14 days of stopping an MAOI. Adverse effects are likely to be worse with alcohol.

Tricyclic medications may not be suitable for people with certain medical conditions or taking certain medications, such as anticholinergic agents. Tell your doctor if you have had any of the following health problems:

• Heart disease
• Seizures / epilepsy
• Glaucoma
• Urinary retention
• Overactive thyroid gland
• Drug-related hyperpyrexia.

It may be advisable to have an electrocardiograph before treatment and repeat it after a few weeks. Tricyclic drugs are dangerous in overdose.