A Food and Drug Administration advisory in 2006 warned against the off-label use of quinine sulfate and its derivatives in the treatment of muscle cramps. Physicians are faced with a difficult scenario in choosing a treatment regimen for patients with muscle cramps. This American Academy of Neurology assessment systematically reviews the available evidence on the symptomatic treatment of muscle cramps.

American Academy of Neurology (AAN) has released guidelines titled Symptomatic treatment for muscle cramps in February 2010 and Reaffirmed on July 16, 2022. The guidelines have been endorsed by the American Association of Neuromuscular and Electrodiagnostic Medicine.
Following are its major recommendations:
1. Data are insufficient to support or refute the efficacy of calf stretching in reducing the frequency of muscle cramps (Level U).
2. Although likely effective (Level A), the use of quinine derivatives for treatment of cramps should be avoided for routine treatment of cramps. These agents should only be considered when cramps are very disabling, no other agents relieve symptoms, and there is careful monitoring of side effects. They should only be used after informing the patient of the potentially serious side effects.
3. Naftidrofuryl, diltiazem, and vitamin B complex may be considered for the treatment of muscle cramps (Level C).
Note:
A = Established as effective, ineffective or harmful (or established as useful/predictive or not useful/predictive) for the given condition in the specified population. (Level A rating requires at least two consistent Class I studies.)* B = Probably effective, ineffective or harmful (or probably useful/predictive or not useful/predictive) for the given condition in the specified population. (Level B rating requires at least one Class I study or two consistent Class II studies.) C = Possibly effective, ineffective or harmful (or possibly useful/ predictive or not useful/predictive) for the given condition in the specified population. (Level C rating requires at least one Class II study or two consistent Class III studies.) U = Data inadequate or conflicting; given current knowledge, treatment (test, predictor) is unproven.
Reference:
Hans D. Katzberg, Ahmir H. Khan, Yuen T. So Neurology Feb 2010, 74 (8) 691-696; DOI: 10.1212/WNL.0b013e3181d0ccca