FDA: MedGuide Created To Cut Off-Label Use of Quinine Product

The off-label use of quinine (an anti-malarial drug) for restless leg is warned against by FDA in MedGuide due to the risk of serious adverse events which could outweigh the benefits. Read more here - http://www.webmd.com/pain-management/news/20061212/fda-dont-use-quinine-leg-cramps

The warnings about possible side effects include:

• Potentially serious interactions with other drugs
• Abnormal heart rhythms that can lead to death
  
• Thrombocytopenia, a blood platelet disorder that can cause hemorrhage or clotting problems
• Severe hypersensitivity reactions

Signs and symptoms to inform the doctor immediately if one should experience while taking quinine:

• easy bruising • severe flushing
• severe nose bleed • swelling of your face
• blood in urine or stool • trouble breathing
• bleeding gums • chest pain
•appearance of unusual purple, brown or red spots on your skin (bleeding under your skin)
• rapid heartbeat
• irregular heart rhythm
•rash
• weakness
• sweating
•severe itching
• nervousness

DO NOT take quinine if you have:

• certain heart rhythm problems
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency
• an autoimmune disease (myasthenia gravis) that leads to muscle weakness.
• had allergic reactions to quinine, quinidine, or mefloquine (Lariam®).
• had serious side effects to quinine, such as low platelets count
• an inflammation of the nerve important for vision (optic neuritis).

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Side note

For patients with persistent symptoms, here are some other Rx medicines options for treatment:

  

Dopamine agonists (pramipexole, ropinirole) are often tried first for patients with daily symptoms. 

Tell patients to take them about 2 hours before bedtime...but caution about nausea, dizziness, sleepiness, and impulse control problems such as compulsive gambling or shopping. Suggest giving half the dose earlier in the day if symptoms worsen or occur earlier. 

Carbidopa/levodopa can help with intermittent symptoms. Suggest trying one-half or one 25/100 mg tab before bedtime or a 25/100 mg CR tab if the effects wear off before morning. 

Gabapentin can help patients who don't tolerate dopamine agonists or whose symptoms include pain or unpleasant sensations. Suggest starting with gabapentin 100 to 300 mg up to two hours before bedtime...titrating up to about 1800 mg/day if needed.

For doses over 600 mg/day, recommend taking half the dose in the late afternoon and the rest up to 2 hours before bedtime.
Horizant a new Gabepentin extended release formulation is better absorbed and longer-acting than normal gabapentin. 

Source: Pharmacist's Letter: July 2011; Vol: 27, No. 7

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