Tizanidine
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Pronunciation | /taɪˈzænɪdiːn/ tye-ZAN-i-deen |
Trade names | Zanaflex, Sirdalud, and others |
Other names | 4-Chloro-N-(4,5-dihydro-1H-imidazol-2-yl)-8-thia-7,9-diazabicyclo[4.3.0]nona-2,4,6,9-tetraen-5-amine |
AHFS/Drugs.com | Monograph |
MedlinePlus | a601121 |
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Routes of administration | By mouth |
Drug class | α2-adrenergic receptor agonist |
ATC code | |
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Pharmacokinetic data | |
Bioavailability | ~40%[1] |
Protein binding | ~30% |
Metabolism | Liver (CYP1A2, 95%) |
Elimination half-life | 2.54 hours (tizanidine), 20–40 hours (inactive metabolites)[1] |
Excretion | Urine (60%), feces (20%) |
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Tizanidine, sold under the brand name Zanaflex among others, is an
Common side effects of tizanidine include
Tizanidine was approved for medical use in the United States in 1996.
Medical uses
Tizanidine has been found to be as effective as other antispasmodic drugs and is more tolerable than baclofen and diazepam.[4]
Side effects
Side effects include dizziness, drowsiness, weakness, nervousness, confusion, hallucinations, strange dreams, depression, vomiting, dry mouth, constipation, diarrhea, stomach pain, heartburn, increased muscle spasms, back pain, rash, sweating, and a tingling sensation in the arms, legs, hands, and feet.[9]
Symptoms of
Interactions
- antibiotics such as enoxacin, gatifloxacin, levofloxacin, lomefloxacin, moxifloxacin, ofloxacin, sparfloxacin, trovafloxacin, or norfloxacin;
- blood pressure medications such as clonidine, guanabenz, guanfacine (Tenex), or methyldopa;
- heart rhythm medications such as amiodarone (Cordarone, Pacerone), mexiletine (Mexitil), propafenone (Rhythmol), and verapamil (Calan, Covera, Isoptin).
Pharmacology
Tizanidine is an α2 receptor agonist closely related to clonidine. It has approximately one tenth to one fifteenth of the blood pressure lowering effect of clonidine. The relation between the α2 receptor agonism and the spasmolytic action is still not fully understood.[2]
Site | Ki (nM) | Species | Ref |
---|---|---|---|
α2A | 62 | Human | [15] |
α2B | 75 | OK | [15] |
α2C | 76 | Rat | [15] |
Route of administration
Tizanidine is available as a tablet or capsule. Capsules may be opened and sprinkled on food. However, this may change the absorption of the medication compared to taking the capsule whole.[16] It has a volume of distribution of 2.4 L/kg following intravenous administration.[1]
Chemistry
Tizanidine is a derivative of
using iron and acetic acid.The amine intermediate was treated with
References
- ^ a b c d e "Zanaflex (tizanidine hydrochloride) Capsules and Tablets for Oral Use. Full Prescribing Information" (PDF). Acorda Therapeutics Inc. Ardsley, NY 10502. Retrieved 1 September 2016.
- ^ OCLC 1015240036.
- ^ ISBN 9780857113382.
- ^ S2CID 73086671.
- ^ a b c d e "Tizanidine Hydrochloride Monograph for Professionals". Drugs.com. American Society of Health-System Pharmacists. Retrieved 3 March 2019.
- ^ "Tizanidine Pregnancy and Breastfeeding Warnings". Drugs.com. Retrieved 3 March 2019.
- ^ "The Top 300 of 2021". ClinCalc. Archived from the original on 15 January 2024. Retrieved 14 January 2024.
- ^ "Tizanidine - Drug Usage Statistics". ClinCalc. Retrieved 14 January 2024.
- ^ "Page not available". PubMed Health. Archived from the original on 11 November 2012. Retrieved 4 September 2017.
- S2CID 38946270.
- ^ "Tizanidine Uses, Dosage, Side Effects – Drugs.com". drugs.com. Retrieved 4 September 2017.
- ^ NHS Wales (2011). "Tizanidine (Zanaflex) Gwent Primary Care Prescribing Guidance" (PDF). Aneurin Bevan University Health Board.
- ^ "Tizanidine package leaflet: Information for the user" (PDF). Medicines and Healthcare products Regulatory Agency (UK). 2016. Archived from the original (PDF) on 16 September 2018. Retrieved 16 September 2018.
- ^ "Zanaflex (tizanidine hydrochloride) dose, indications, adverse effects, interactions... from PDR.net". www.pdr.net. Retrieved 16 September 2018.
- ^ PMID 1656026.
- ^ "Tizanidine: MedlinePlus Drug Information". medlineplus.gov. U.S. National Library of Medicine. Retrieved 29 October 2019.
- ^ a b US patent 3843668, Neumann P, "Certain 4-substituted amino-2,1,3-benzothiadiozoles", published 1974-10-22, assigned to Sandoz AG
- S2CID 98830770.
- ^ "Pharmaceutical Substances: Tizanidine". Thieme. Retrieved 16 February 2023.