Duloxetine - Important warnings and side-effects

Food and Drug Administration (FDA) warnings

The FDA has allocated a ‘black box warning’ for this medication which effectively alerts both medical professionals and patients that the drug carries potentially dangerous side-effects for some individuals. All doctors prescribing this medication will know this and take extra care when recommending the medication to certain individuals. A black box warning medication is always used with care and taken very seriously.

The warning relates to documented side-effects that have noted an increased risk of suicide and associated behaviours in those being treated for a major depressive disorder, aged 24 and younger. It has also been noted that during the initial stages of treatment, symptoms of depression can worsen and lead to thoughts of suicide. Teenagers and young adults may become highly agitated, irritable and more depressed. Some have trouble sleeping, engage in reckless behaviours, get upset easily or experience a spike in energy levels. Any such symptoms should be reported to your doctor right away.

Before any prescription is recommended for treatment your doctor will check both your personal and family history of possible psychiatric disorders. If there is any history of manic-depressive or bipolar disorder, or instances of suicidal attempts (including successful suicides), he or she may not recommend this medication.

The medication is also capable of causing severe drowsiness which can impair the ability to make sound decisions, think or react clearly and quickly. It is not recommended that anyone on this medication be allowed to drive or operate heavy or potentially dangerous machinery (at least until the body has settled on the drug and a doctor has assessed you as ‘well-adjusted’ on the medication).

The warning also relates to a potentially serious complication known as serotonin syndrome. Side-effects include confusion and agitation, sweating, loss of coordination, as well as an increased heart rate and blood pressure. If severe, this condition can be fatal. A sudden drop in blood pressure is also potentially problematic and is included in the warning as well.

General side effects and potential complications

Taking this medication to treat a condition is not without some side-effects. Your doctor will have weighed the benefits against possible side-effects before prescribing the medication. The benefit must be greater than the risk. Normally, side-effects experienced are not serious and typically occur in the initial stage of treatment or during dosage changes as the body adjusts. Your doctor will help you to manage side-effects throughout your treatment.

The list of noted side-effects is not applicable to all, but any that are experienced must be reported to your doctor as soon as possible, so as to avoid any potential damage or medical complications. Some are considered more serious than others and could indicate damage to the liver, changes in blood pressure levels, serotonin syndrome or abnormal bleeding in the body.

It is not unusual for you to experience changes in blood pressure while on this medication. Your doctor will request follow-ups periodically to check for any higher than normal levels.

The list of side-effects includes:

• Headache
• Skin rashes, blisters, peeling of the skin or severe acne
• Inflamed skin (redness) or lesions (red with a purplish centre)
• Itching, welts or hives on the skin (the face, eyelids, tongue, lips, throat, limbs, hands, feet and sex organs), as well as swelling (puffiness) on or around the eyes, lips, tongue or face
• Swelling of the face, hands and ankles
• Ulcers, sores or white spots on the lips or inside the mouth
• Unpleasant breath odour
• Dry mouth
• Changes in ability to taste (or loss of taste)
• Breathing problems
• Yellowing of the eyes and skin (jaundice)
• Abdominal pain
• Tightness in the chest
• Vomiting of blood or substances that resemble dark coffee grounds
• Visual disturbances (such as blindness, widened pupils, decreased vision or blurred vision)
• Eye pain and inflammation (redness of the eyes)
• Eye tearing
• Ear congestion
• Sore throat
• Runny or stuffy nose
• Body chills and cold sweats
• Noticeable changes in consciousness or loss of consciousness
• Convulsions, seizures, twitching muscles or tremors (shaking)
• Confusion, light-headedness and dizziness
• Feeling faint
• Fatigue, drowsiness and body weakness
• Difficulty with swallowing
• Coughing
• Clay-coloured or light coloured stools (faeces)
• Black or bloody stools (faeces)
• Constipation or diarrhoea
• Bowel movement difficulties or loose stools
• Problems with urination (dark urine, difficulties with urinating or decreased urine flow)
• A fast or irregular heartbeat
• Sweating (increased or profuse)
• Bruising or bleeding easily
• Increased thirst
• Joint and muscle pain, muscle cramps or stiffness
• Swollen joints
• Movement difficulties
• Loss of appetite
• Lack of libido (interest in sex or changes in sexual ability such as abnormal orgasms, problems with the discharge of semen or ejaculation or the inability to have or maintain an erection)
• Persistent nausea and vomiting
• Hallucinations
• Unexplained fever
• Unexplained weight loss or decreased weight
• Coma
• Manic episodes (including severe sleeping problems, racing thoughts, increased energy levels, reckless behaviour, excessive agitation, irritability or happiness, unusually grand ideas, and excessive talking or faster than usual)
• Belching
• An acidic or sour stomach
• Sensations of crawling, burning, itching, prickling, tingling or numbness
• Heartburn and indigestion

Signs of overdose

Symptoms experienced with overdose require emergency medical attention. These include:

• Fever
• Diarrhoea (especially in children)
• Loss of bladder control
• Severe agitation
• Overactive reflexes, muscle spasms, twitching, trembling, jerking in the extremities, shivering and restlessness
• Vomiting
• Profuse or increased sweating
• Unexplained drowsiness, fatigue, weakness, sleepiness and poor coordination
• Sudden loss of consciousness
• Uncontrolled behaviour (talking or acting with excitement)

Withdrawal symptoms

Many individuals do experience side-effects of discontinuation. Withdrawal symptoms are to be expected and your doctor will likely warn you of the following possibilities, as well as help you to best manage them:

• Headaches
• Dizziness
• Nausea and vomiting
• Fatigue or lethargy
• Irritability or anxiety
• Sleeping problems or insomnia
• Excessive sweating (hyperhidrosis)
• Diarrhoea
• Seizures
• Paraesthesia (electric shock or prickling sensations, also known as ‘brain zaps’ or ‘lightning bolt syndrome’)
• Nightmares
• Personality changes, extreme mood swings and emotional lability (pathological laughing or crying)
• Ringing in the ears (tinnitus)

Not all symptoms may be experienced and those that are range from mild to severe, as well as for different durations. It is highly likely that you will remain in close contact with your doctor from the time of prescription, through your treatment period and during discontinuation. He or she will conduct checks periodically and ensure that you are well adjusted on (and off) the medication.

If any new symptoms develop or you feel concerned, it is advisable to consult your doctor to discuss as soon as possible.