Topical pharmaceutical composition containing phenytoin and a (co-) analgesic for the treatment of chronic pain

1. A pharmaceutical composition, wherein active pharmaceutical ingredients thereof consist of:

a) a first co-analgesic selected from phenytoin or a prodrug, a stereoisomer, and/or a salt thereof, or any combination thereof;

b) at least one further (co-)analgesic; and

c) a pharmaceutically acceptable carrier for topical use,

wherein the at least one further (co-)analgesic of b) is a combination of baclofen and amitriptyline, or loperamide and amitriptyline, or baclofen and loperamide, and/or a salt thereof, or wherein the at least one further (co-)analgesic of b) is selected from amitriptyline, baclofen, loperamide, and/or a salt thereof.

2. The pharmaceutical composition of claim 1 , wherein the active pharmaceutical ingredients consist of:

a) the first co-analgesic is selected from phenytoin and/or a salt thereof, or any combination thereof;

b) one further (co-)analgesic; and

c) a pharmaceutically acceptable carrier for topical use,

wherein the one further (co-)analgesic of b) is selected from the group consisting of amitriptyline, baclofen, loperamide, and a salt of any thereof.

3. The pharmaceutical composition of claim 1 , wherein the pharmaceutically acceptable carrier for topical use is selected from the group consisting of a cream, a gel, a dispersion, an emulsion, a foam, a mist, a mouth wash, a lotion, a salve, an ointment, an oil, a spray, an aerosol, a suppository, a suspension, a plaster, and a passive or active topical device for absorption through skin and mucous membrane.

4. The pharmaceutical composition of claim 3 , wherein the pharmaceutically acceptable carrier for topical use is a cream.

5. The pharmaceutical composition of claim 1 , wherein the pharmaceutically acceptable carrier for topical use comprises at least one skin penetration enhancer.

6. The pharmaceutical composition of claim 5 , wherein the pharmaceutically acceptable carrier for topical use comprises at least one skin penetration enhancer selected from the group consisting of macrogol cetostearyl ether, cetostearyl alcohol, decylis oleas, and any combination thereof.

7. The pharmaceutical composition of claim 1 , wherein the first co-analgesic is between 0.5% to 20% phenytoin and/or phenytoin sodium, and

wherein the at least one further (co-)analgesic is selected from about 5% baclofen and about 5% loperamide, or

wherein the at least one further (co-)analgesic is a combination of about 5% baclofen and about 5% amitriptyline, or loperamide 5% and baclofen 5% by weight of the pharmaceutical composition.

8. The pharmaceutical composition of claim 1 , wherein the first co-analgesic is between 5% and 20% phenytoin and/or phenytoin sodium by weight of the pharmaceutical composition, and

wherein the at least one further (co-)analgesic is selected from about 5% baclofen by weight of the pharmaceutical composition and about 5% loperamide by weight of the pharmaceutical composition, or

wherein the at least one further (co-)analgesic is a combination of about 5% baclofen and about 5% amitriptyline by weight of the pharmaceutical composition, or loperamide 5% and baclofen 5% by weight of the pharmaceutical composition.

9. The pharmaceutical composition of claim 1 , wherein the first co-analgesic is between 5% and 20% phenytoin and/or phenytoin sodium by weight of the pharmaceutical composition, and wherein the at least one further (co-)analgesic is about 10% amitriptyline by weight of the pharmaceutical composition.

10. A method for treating chronic pain, the method comprising:

administering the pharmaceutical composition of claim 1 to an individual in need thereof,

wherein the chronic pain is selected from the group consisting of neuropathic pain, peripheral neuropathic pain, inflammatory pain, musculoskeletal pain, pain due to muscle spasms, pain due to increased muscle tone, osteoarthritic pain, muscular headache, tension-type headache, migraine, cluster headache, atypical facial pain, referred pain, vulvodynia, proctodynia, and any combination thereof.

11. The method according to claim 10 , wherein the chronic pain is peripheral neuropathic pain.

12. A method for treating chronic pain, the method comprising:

administering a pharmaceutical composition to an individual in need thereof, wherein active pharmaceutical ingredients of the pharmaceutical composition consist of:

a) a first co-analgesic selected from phenytoin or a prodrug, a stereoisomer, and/or a salt thereof, or any combination thereof;

b) at least one further (co-)analgesic, and

c) a pharmaceutically acceptable carrier for topical use,

wherein the at least one further (co-)analgesic of b) is a combination of baclofen and amitriptyline, or loperamide and amitriptyline, or baclofen and loperamide, and/or a salt thereof, or wherein the at least one further (co-)analgesic of b) is selected from amitriptyline, baclofen, loperamide, and/or a salt thereof, and

wherein the chronic pain is neuropathic pain selected from peripheral neuropathy caused by diabetes type 1 or 2, or induced by a noxious substance such as alcohol, due to vitamin B1, B6 and/or B12 deficiency, hypervitaminosis B6, hypothyroidism, chemotherapeutic compound such as paclitaxel or a taxane derivative, vincristine or a vinca alkaloid, cisplatin or a platinum derivate, drug-induced neuropathy, a compound for treatment of infectious disease such as streptomycin, didanosine or zalcitabine, a chemically toxic compound, trigeminal neuralgia, post-herpetic neuralgia, intercostal neuralgia, entrapment neuropathy such as carpal tunnel syndrome, tarsal tunnel syndrome, abdominal cutaneous nerve entrapment syndrome, small fiber neuropathy, hereditary motor and sensory neuropathies, chronic inflammatory demyelinating polyneuropathy, sciatic pain chronic idiopathic sensory neuropathy, infectious disease conditions such as post-polio syndrome, AIDS or HIV-associated, Lyme-associated, Sjögren-associated, lymphomatous neuropathy, myelomatous neuropathy, carcinomatous neuropathy, vasculitic/ischaemic neuropathy and a mono- and polyneuropathy, complex regional pain syndrome type I and II (reflex sympathetic dystrophy), central neuropathic pain such as thalamic neuropathy, spinal cord injury neuropathy, post stroke pain, multiple sclerosis neuropathy, syringomyelia, a spinal cord tumor, phantom limb pain, restless genital syndrome with pain, post-surgical scar pain including cardiac surgery and mastectomy.

13. The method according to claim 10 , having a dosing frequency of the pharmaceutical composition of between once every other day and eight times daily.

14. The method according to claim 10 , wherein the pharmaceutical composition is administered to the individual during a period of at least one week.

15. The method of claim 10 , wherein the pharmaceutical composition is administered chronically.

16. The method according to claim 10 , wherein the first co-analgesic is between 0.5% to 20% phenytoin and/or phenytoin sodium by weight of the pharmaceutical composition, and wherein the at least one further (co-)analgesic is selected from about 5% baclofen and about 5% loperamide by weight of the pharmaceutical composition, or wherein the at least one further (co-)analgesic is the combination of about 5% baclofen and about 5% amitriptyline, or loperamide 5% and baclofen 5% by weight of the pharmaceutical composition.

17. The method according to claim 10 , wherein the first co-analgesic is between 5% to 20% phenytoin and/or phenytoin sodium by weight of the pharmaceutical composition, and wherein the at least one further (co-)analgesic is selected from about 5% baclofen by weight of the pharmaceutical composition and about 5% loperamide by weight of the pharmaceutical composition, or wherein the at least one further (co-)analgesic is the combination of about 5% baclofen and about 5% amitriptyline by weight of the pharmaceutical composition, or loperamide 5% and baclofen 5% by weight of the pharmaceutical composition.

18. The method according to claim 10 , wherein the first co-analgesic is between 5% and 10% phenytoin and/or phenytoin sodium by weight of the pharmaceutical composition, and wherein the at least one further (co-)analgesic is selected from about 5% baclofen by weight of the pharmaceutical composition and about 5% loperamide by weight of the pharmaceutical composition, or wherein the at least one further (co-)analgesic is the combination of about 5% baclofen and about 5% amitriptyline by weight of the pharmaceutical composition, or loperamide 5% and baclofen 5% by weight of the pharmaceutical composition.