chlorzoxazone


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relaxant

 [re-lak´sant]
1. causing relaxation.
2. an agent that causes relaxation.
muscle relaxant an agent that specifically aids in reducing muscle tension.

chlorzoxazone

Parafon Forte DSC, Strifon Forte (CA)

Pharmacologic class: Autonomic nervous system agent

Therapeutic class: Skeletal muscle relaxant (centrally acting)

Pregnancy risk category C

Action

Unclear. Thought to act on spinal cord and subcortical levels of brain, inhibiting multisynaptic reflex arcs responsible for skeletal muscle activity.

Availability

Caplets: 500 mg

Tablets: 250 mg, 500 mg

Indications and dosages

Adjunct to rest and physical therapy in treatment of muscle spasms associated with acute, painful musculoskeletal conditions

Adults: 250 to 750 mg P.O. three to four times daily

Contraindications

• Hypersensitivity to drug

• Hepatic impairment

Precautions

Use cautiously in:

• underlying cardiovascular disease, renal impairment

• children (safety not established).

Administration

• If desired, crush tablets and mix contents with food or water.

• Don't withdraw drug abruptly.

Adverse reactions

CNS: dizziness, drowsiness, light-headedness, malaise, headache, over-stimulation, tremor

GI: nausea, vomiting, constipation, diarrhea, heartburn, abdominal distress, anorexia

GU: orange or purplish-red urine

Hepatic: hepatic dysfunction

Skin: allergic dermatitis, urticaria, erythema, pruritus, petechiae, ecchymosis, angioedema

Other: allergic reactions

Interactions

Drug-drug. CNS depressants (including antihistamines, antidepressants, opioids, sedative-hypnotics): increased risk of CNS depression

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, bilirubin: increased levels

Drug-herbs. Chamomile, hops, kava, skullcap, valerian: increased CNS depression

Drug-behaviors. Alcohol use: increased sedation

Patient monitoring

Stay alert for signs and symptoms of hepatic dysfunction. Withhold drug and notify prescriber if these occur.

• Monitor hepatic enzyme and serum electrolyte levels.

Patient teaching

Instruct patient to promptly report yellowing of eyes or skin.

• Caution patient not to consume alcohol during therapy.

• Instruct patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.

• Tell patient that drug may turn his urine orange or purplish-red.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.

References in periodicals archive ?
This study was conducted to compare the efficacy of Thiocolchicoside and chlorzoxazone. The main goal of the pharmacological intervention in low back pain is not only relief from the pain, but also to reduction of the muscle spasm and inflammation.
Tyndale, "Phenobarbital induces monkey brain CYP2E1 protein but not hepatic CYP2E1, in vitro or in vivo chlorzoxazone metabolism," European Journal of Pharmacology, vol.
As shown in Table 3, the extraction rate for caffeine, chlorzoxazone, tolbutamide, and midazolam was ideal which ranged from 85.65% to 99.18%.
The effects of different FA treatments on the pharmacokinetic parameters of chlorzoxazone in rats are presented in Table 2.
Effect of fasting and obesity in humans on the 6-hydroxylation of chlorzoxazone: a putative probe of CYP2E1 activity.
Briefly, 20 [micro]L of drug probes (25 [micro]mol phenacetin and 25 [micro]mol chlorzoxazone) was added to a 5 mL microcentrifuge tube and volatilized to dry.
It was uncovered to stimulate cytochrome P450 enzyme and thus reduce the plasma level of a wide range of conventional drugs including warfarin, voriconazole, verapamil, talinolol, tacrolimus, simvastatin, quazepam, oral contraceptives, omeprazole, nifedipine, midazolam, methadone, mephenytoin, ivabradine, irinotecan, indinavir, imatinib, gliclazide, fexofenadine, erythromycin, digoxin, debrisoquine, ciclosporin, chlorzoxazone, atorvastatin, amitriptyline, and alprazolam [114-116].
Aceclofenac 100 mg + Chlorzoxazone 250 mg + Paracetamol 325 mg combination and 2.
For example, they say, chlorzoxazone is one product where Barr and Teva have nearly all of the worldwide market share.
Key words: chlorzoxazone, CYP2E1 mRNA induction, lymphocytes, occupational exposure, toluene.
Decrease in cytochrome P4502E1 as assessed by the rate of chlorzoxazone hydroxylation in alcoholics during the withdrawal phase.