Myolastan®
50 mg Film-Coated Scored Tablets — Tetrazepam
1. Disclaimer
This information is provided for educational and reference purposes only and is not a substitute for the official product information, prescribing information, or advice of a qualified healthcare professional.
We do not guarantee the accuracy, currency or completeness of information regarding medications or medical products, and official sources should be verified before making any decisions. Readers are responsible for independently verifying the information before relying on it.
Because tetrazepam-containing medicines have been withdrawn or suspended in the European Union because of serious, potentially life-threatening cutaneous reactions, and because publicly available Egyptian-market records do not consistently establish current authorization for sale, the regulatory status of any locally listed product should be independently confirmed with the competent Egyptian authority or the current official package leaflet.
2. Summary
Myolastan® 50 mg is a film-coated, scored oral tablet containing tetrazepam, a benzodiazepine derivative with centrally acting skeletal-muscle-relaxant properties. The product was historically used as adjunctive treatment for painful muscle contractures and spasticity.
The presentation Myolastan 50 mg, 20 coated tablets is still indexed in several Egyptian drug-reference databases and is associated with Global Napi Pharmaceuticals, but these listings should not by themselves be interpreted as proof of a currently valid marketing authorization or unrestricted legal sale.
Tetrazepam has an important safety history: in 2013, the European Commission adopted a legally binding decision suspending the marketing authorisations of tetrazepam-containing medicines throughout the EU because the benefit-risk balance was considered unfavorable, principally because of serious cutaneous adverse reactions including Stevens–Johnson syndrome, toxic epidermal necrolysis and DRESS.
3. Brand Name
Myolastan®
The referenced Egyptian presentation is:
Myolastan 50 mg 20 coated tab
Tetrazepam is the active pharmaceutical ingredient.
4. Category
Therapeutic category: Centrally acting skeletal muscle relaxant.
Pharmacological class: Benzodiazepine derivative.
ATC classification: M03BX07 — Tetrazepam, within M03B centrally acting muscle relaxants and M03BX other centrally acting agents.
The classification found in some Egyptian drug directories as “Psychiatric.anxiolytics-hypnotics” appears to be a database categorization and should not replace the pharmacological/ATC classification of tetrazepam as a centrally acting muscle relaxant.
5. Active Ingredient
Tetrazepam — 50 mg per tablet.
Tetrazepam is a 1,4-benzodiazepine derivative.
6. Pharmaceutical Form & Strength
Pharmaceutical form: Film-coated, scored tablet.
Strength: 50 mg tetrazepam per tablet.
Presentation: Box containing 20 scored film-coated tablets.
7. Manufacturer & Marketing Authorization Holder
Egyptian product/manufacturer listing: Global Napi Pharmaceuticals, Egypt. Current Egyptian drug-reference databases associate Myolastan 50 mg with Global Napi Pharmaceuticals.
Historical Myolastan packaging/product information identified Sanofi-Synthélabo, France in connection with the licensed product. Because Sanofi-Synthélabo is a historical corporate designation, this wording should not be presented as confirmation of a current marketing-authorisation holder.
Current Egyptian MAH: No sufficiently authoritative, publicly indexed Egyptian regulatory source was found that independently confirms the current marketing-authorisation holder for this presentation. Therefore, a current MAH should not be inferred solely from commercial drug-directory listings.
8. Mechanism of Action
Tetrazepam is a benzodiazepine receptor agonist/modulator that enhances the inhibitory effects of gamma-aminobutyric acid (GABA) at central benzodiazepine-sensitive GABA-A receptor complexes. Increased GABAergic inhibition reduces neuronal excitability and produces central nervous system effects, including muscle-relaxant and sedative effects.
Its clinically relevant historical use was principally as a centrally acting muscle relaxant for painful contractures and spasticity rather than as an antimicrobial or peripheral neuromuscular blocker.
9. Spectrum of Activity
Not applicable.
Tetrazepam is not an antimicrobial drug and therefore does not have an antibacterial, antifungal, antiviral, or antiparasitic spectrum of activity.
10. Pharmacokinetics
Tetrazepam is absorbed rapidly after oral administration. In pharmacokinetic studies using a 50 mg tablet, peak plasma concentrations were reached approximately 1 hour to 2 hours after administration, depending on the study. Reported elimination half-lives were approximately 15 hours in one study and about 22 hours in another, indicating substantial inter-study variability.
The drug is extensively distributed and undergoes hepatic metabolism. Studies identified hydroxylation, N-demethylation and glucuronidation among its metabolic pathways; only relatively small concentrations of active metabolites were observed in early pharmacokinetic investigations, with pharmacological activity attributed mainly to the parent compound.
Because the available pharmacokinetic literature is relatively old and tetrazepam has been withdrawn/suspended in major markets, modern population pharmacokinetic data are limited.
11. Indications
Historically, Myolastan/tetrazepam was indicated as adjunctive treatment of painful muscle contractures, including those associated with:
- Degenerative vertebral disorders and vertebral static disturbances, such as torticollis, dorsalgia and lumbar pain.
- Traumatological disorders.
- Neurological contractures associated with spasticity.
- Functional rehabilitation.
These indications are consistent with the historical European product information and the EMA description of tetrazepam's authorized uses before the 2013 suspension.
These historical indications should not be interpreted as evidence that tetrazepam remains currently authorized for those uses in every country.
12. Administration
Route: Oral.
The historical Myolastan 50 mg product was administered as scored tablets intended for oral use. Historical product information described adult treatment as beginning with 50 mg at bedtime, with gradual adjustment where necessary and a historical maximum of 100 mg/day in the referenced product information.
However, because the original dosing information is historical and tetrazepam's regulatory status and safety profile have subsequently changed substantially, these figures should not be presented as a current prescribing recommendation without confirmation from the current national official product information.
The historical source also described lower dosing in elderly patients and a pediatric regimen. Those historical pediatric instructions should not be used as current dosing guidance. In particular, the later European safety review considered pediatric use among potential risk-minimisation concerns, while the final EU regulatory action was suspension of tetrazepam-containing medicines.
13. Method of Preparation
No preparation or reconstitution is required.
The product is supplied as a ready-to-use film-coated tablet for oral administration. The tablet is scored; whether the score is intended for dose division should be confirmed from the applicable official product information for the particular market.
14. Contraindications
The historically referenced product information lists:
- Known hypersensitivity to benzodiazepines.
- Severe respiratory insufficiency.
In addition, the serious cutaneous safety findings identified during the European regulatory review are highly important. Severe cutaneous reactions associated with tetrazepam included Stevens–Johnson syndrome, toxic epidermal necrolysis, erythema multiforme and DRESS. These reactions were considered unpredictable and could occur even after short-term treatment and at recommended doses.
15. Warnings & Precautions
Particular caution is warranted because tetrazepam is a benzodiazepine and can cause central nervous system depression.
Important precautions include:
- Serious skin reactions: New or rapidly progressive rash, blistering, mucosal lesions, skin peeling, fever, or systemic symptoms require urgent medical assessment because severe cutaneous adverse reactions have been associated with tetrazepam.
- Sedation and impaired psychomotor performance: Somnolence may impair driving and operation of machinery.
- Alcohol: Alcohol should be avoided because of additive central nervous system depression.
- Other CNS depressants: Concurrent use with other sedating medicines can increase impairment and respiratory-depressant effects.
- Dependence and withdrawal: As a benzodiazepine, prolonged or repeated exposure may lead to physical dependence. Abrupt discontinuation after prolonged treatment should therefore be avoided; discontinuation should be medically supervised.
- Respiratory disease: Additional caution is appropriate in patients with impaired respiratory function.
- Older adults: Increased sensitivity to sedation, impaired coordination and falls may be clinically important.
- Driving: Patients should not drive or operate machinery if affected by somnolence or impaired alertness.
16. Drug Interactions
The most clinically important interaction is additive central nervous system depression with other CNS depressants.
Particular caution is required with:
- Alcohol.
- Opioid analgesics and other opioid-containing medicines.
- Other benzodiazepines and sedative-hypnotics.
- Sedating antihistamines.
- Antipsychotics and other centrally sedating medicines.
- General anaesthetic agents and other potent CNS depressants.
- Other centrally acting muscle relaxants.
Such combinations can increase drowsiness, impaired coordination and, particularly with potent CNS depressant combinations, respiratory depression.
Because tetrazepam undergoes hepatic metabolism and the historical pharmacokinetic literature is limited, potentially significant metabolic interactions should be assessed from the specific co-medication and current professional reference rather than inferred from a generic CYP interaction list.
17. Side Effects
Reported or recognized adverse effects include:
Common/recognized CNS effects
- Somnolence.
- Reduced alertness.
- Dizziness or impaired coordination may occur with benzodiazepine therapy.
Cutaneous reactions
- Skin eruptions.
- Hypersensitivity reactions.
- Rare but potentially life-threatening severe cutaneous adverse reactions.
The European pharmacovigilance review identified 513 cutaneous or allergic reactions associated with the originator product Myolastan in its database, including 65 reported cases of Stevens–Johnson syndrome or toxic epidermal necrolysis. The review concluded that the risk of serious skin reactions was increased compared with other benzodiazepines.
18. Use in Special Populations
Pregnancy: Tetrazepam should not be considered a routine medicine during pregnancy. Benzodiazepines can cross the placenta, and exposure near delivery may produce neonatal CNS and respiratory effects; the European safety assessment also identified pregnancy as an area of concern in proposed risk-minimisation measures.
Breastfeeding: Evidence specific to tetrazepam is limited. Benzodiazepines may be excreted into breast milk and can cause sedation or feeding problems in infants. Use during breastfeeding requires specialist assessment, and a safer alternative may be preferred.
Children: Historical product information described use in children above 1 year only when treatment was unavoidable. This should not be regarded as contemporary pediatric dosing guidance. The later European safety review considered contraindication in children and adolescents as a possible risk-minimisation measure, and tetrazepam-containing medicines were subsequently suspended throughout the EU.
Elderly patients: Reduced doses were historically recommended because of increased sensitivity to sedation and psychomotor impairment. Current use, if legally authorized in a particular jurisdiction, requires individual assessment of falls, cognition, respiratory status and concomitant CNS depressants.
Renal/Hepatic impairment: Specific current dosing recommendations could not be independently verified from a current Egyptian official product document. Because hepatic metabolism is important, patients with significant hepatic impairment require specialist assessment rather than application of an unverified dose adjustment.
19. Storage Conditions
No sufficiently authoritative, current Egyptian official storage specification was located in the publicly indexed sources reviewed for this entry.
The product should therefore be stored according to the storage conditions printed on the current package/official leaflet for the specific marketed batch, with protection from conditions that could degrade the tablets, and kept out of the reach of children.
20. Additional Sections
Regulatory and Market Status
The most important current safety distinction is between historical product information and present regulatory status.
In the European Union, tetrazepam-containing medicines, including Myolastan, had their marketing authorisations suspended in 2013 after an EU-wide review concluded that the benefit-risk balance was unfavorable because of serious and potentially fatal skin reactions and limited evidence of efficacy. The European Commission adopted the legally binding decision on 29 May 2013.
For Egypt, current online drug directories continue to index Myolastan film-coated tablet 50 mg / 20 tablets and associate it with Global Napi Pharmaceuticals. However, at least one Egyptian drug directory explicitly states that the medicine is not permitted for sale, while other commercial directories continue to display it as a listed product. This inconsistency means that online listings cannot safely be treated as confirmation of an active Egyptian marketing authorization.
Accordingly, the most defensible description for an educational drug database is:
“Myolastan 50 mg remains indexed in Egyptian drug-reference databases, but current Egyptian regulatory authorization and legal market availability should be independently confirmed.”
21. Frequently Asked Questions (FAQ)
What is Myolastan 50 mg?
Myolastan 50 mg is a tetrazepam-containing oral film-coated tablet. Tetrazepam is a benzodiazepine derivative historically used as a centrally acting skeletal muscle relaxant.
What is tetrazepam used for?
Historically, it was used as adjunctive therapy for painful muscle contractures and spasticity, including certain vertebral, traumatic and neurological conditions.
Is tetrazepam a benzodiazepine?
Yes. Tetrazepam is a 1,4-benzodiazepine derivative with centrally acting muscle-relaxant properties.
What is the ATC code for tetrazepam?
The ATC code is M03BX07.
Why is tetrazepam considered a high-safety-interest medicine?
Because it was associated with rare but serious and potentially fatal cutaneous reactions, including Stevens–Johnson syndrome, toxic epidermal necrolysis and DRESS. These reactions were considered unpredictable and could occur even during short-term treatment.
Is Myolastan still available?
It remains listed in some Egyptian drug databases, but online listings are inconsistent regarding legal sale and do not independently establish current regulatory authorization. In the EU, its marketing authorization was suspended in 2013.
Does Myolastan cause drowsiness?
Yes. Somnolence is a recognized effect and may impair driving and operation of machinery.
Can tetrazepam be stopped suddenly?
Abrupt discontinuation after prolonged or repeated benzodiazepine exposure may cause withdrawal symptoms. Discontinuation should therefore be medically supervised.
22. References
- European Medicines Agency (EMA). Tetrazepam-containing medicines — referral. EU-wide suspension and safety review.
- European Medicines Agency (EMA). Recommendation to suspend tetrazepam-containing medicines endorsed by CMDh; serious cutaneous reactions and benefit-risk assessment.
- European Commission. Union Register of medicinal products — tetrazepam, ATC M03BX07; Commission decision of 29 May 2013.
- PubMed. Baumgärtner MG, Cautreels W, Langenbahn H. Biotransformation and pharmacokinetics of tetrazepam in man. Arzneimittelforschung. 1984.
- PubMed. Plasma levels and pharmacokinetics of single and multiple dose of tetrazepam in healthy volunteers.
- PubChem/NCBI. Tetrazepam, CID 25215; pharmacological classification and ATC code M03BX07.
- Egyptian drug-reference listings. Myolastan 50 mg film-coated tablets, Global Napi Pharmaceuticals; current online market-directory records.
Verification note: The original Egyptian-style product text is consistent with historical Myolastan information regarding the 50 mg strength, scored film-coated tablets, historical indications, and historical dosing. However, the original text is not sufficiently up to date as a standalone current monograph, because it omits the major tetrazepam safety/regulatory developments identified since its original publication. The principal corrections incorporated above are the explicit benzodiazepine classification, ATC code, serious cutaneous-reaction warning, EU regulatory suspension, dependence/withdrawal considerations, and the distinction between historical dosing information and currently verified prescribing guidance.