Class
- Antimalarial, neuromuscular drug
Quinine Sulfate
Commonly Prescribed for
(FDA approved in bold)
- Malaria
- Symptomatic myotonia (myotonia congenita, myotonic dystrophy)
- Leg cramps
Quinine Sulfate
How the Drug Works
- Quinine has several actions on skeletal muscle. Increases the refractory period by acting on the muscle membrane and sodium channel, decreases motor end-plate excitability, and affects the distribution of calcium within the muscle fiber
Quinine Sulfate
How Long Until It Works
- 1–2 hours
Quinine Sulfate
If It Works
- Continue to use
Quinine Sulfate
If It Doesn’t Work
- Change to an alternative agent
Quinine Sulfate
Best Augmenting Combos for Partial Response or Treatment-Resistance
- Myotonia: Anticonvulsants, such as phenytoin and carbamazepine, are effective. The antiarrhythmic drug mexiletine (also a sodium channel blocker) is an alternative
Quinine Sulfate
Tests
- Obtain baseline ECG due to risk of cardiac arrhythmia (common in myotonic dystrophy)
Adverse Effects (AEs)
Quinine Sulfate
How Drug Causes AEs
- Drug effect of blocking sodium channels
Quinine Sulfate
Notable AEs
- “Cinchonism” is a common set of AEs seen in most patients; includes headache, flushing, vertigo, hearing difficulties, tinnitus, blurry vision, and nausea. More severe symptoms include vomiting, abdominal pain, deafness, and blindness
- Hypersensitivity reactions include flushing, pruritus, rash, fever, tinnitus, and dyspnea
- Chest pain, orthostatic hypotension, hypoglycemia, anorexia, jaundice, and abnormal liver function tests
Quinine Sulfate
Life-Threatening or Dangerous AEs
- Cardiac arrhythmias, including atrioventricular block, atrial fibrillation, QTc prolongation, ventricular fibrillation, ventricular tachycardia, torsades de pointes, and cardiac arrest
- Hemolysis associated with glucose-6-phosphate dehydrogenase deficiency
- Severe hypersensitivity (angioedema)
- Rarely asthma or pulmonary edema
Quinine Sulfate
Weight Gain
- Unusual
Quinine Sulfate
Sedation
- Unusual
