((((((Melian)))))) ~
Paracetamol (known as Tylenol in the U.S.), ibuprofen (known as Advil in the U.S.), and aspirin are over the counter medications. Amitriptyline is an anti-depressant and can cause headaches and dry mouth. (Here's the link for it: http://www.nlm.nih.gov/medlineplus/d...s/a682388.html ) Gabapentin is not typically given for headaches, but to control seizures or for neuropathy.
With thousands of pharmaceuticals, it is preposterous for the doctors to tell you that there isn't anything else to prescribe for your headaches. Speak to a chemist about pain meds, specifically to control headache pain, and see what other options are available. Then do research on line about these meds, then take that information to your GP and demand a script for whichever drug sounds best to you.
And do contact the Autism organization. They may have neuro and even GP referrals for you. Or advocates to help you with your doctor's resistance to treat you.
Another thought ~ take up yoga, meditation, see a Reiki master and have a cleansing treatment. See a chiropractor, see an acupuncturist, look for alternatives for your healing. Find a Naturopath. Examine your diet to see whether you are eating foods which contribute to your headaches. Research headache treatments on the internet, diets for headache control, alternative treatments for headaches.
Be careful discontinuing the Gabapentin. You may need to wean yourself from it, rather than stop it cold turkey. That is generally the better choice with all meds, unless they are causing you a life-threatening reaction.
Hope you find something to relieve your pain soon.
Love & Light,
Rose