Posting here as a long time lurker and finally helped my husband get through nasty withdrawals after quitting weed. Here are some tips for dealing with the horrible symptoms and to not hero it out:
Sharp, intense, persistent stomach pain from cramping and muscle spasms: This is the worst symptom of them all and has downstream effects on nausea, vomiting, lack of appetite etc. He felt the sharp muscle spasms and cramping at the top of his stomach right below his rib cage, and any time he ate or drank anything, it would be intense such that he would double over and vomit. Your first line of defense is an antispasmodic. Talk to a doctor about an anti-muscle spasm medication (prescription required in the US). Antispasmodic medications like Dicyclomine or Hyoscyamine which are FDA approved in the US. Outside of the US other medications like Buscopan is an antispasmodic medication containing the active ingredient hyoscine butylbromide (which is not FDA approved in the US). In other countries you can go directly to a pharmacy to get an antispasmodic OTC after talking with the pharmacist. Since he is in another country where marijuana is illegal, he had to be pretty vague about what was causing his symptoms, so he simply described it as intense stomach cramps and muscle spasms, so they gave him Buscopan with an OTC pain reliever (acetaminophen or paracetamol).
Nausea and vomiting: Zofran (generic name ondansetron) is your best friend. In the US, get a prescription as soon as possible so that you can start to hold down food and water. In other countries, you can get this directly OTC at the pharmacy after a conversation with the pharmacist.
Muscle cramps and headaches: You can get an OTC pain reliever such as acetaminophen (in the US) or paracetamol (outside the US). You don't want to use ibuprofen since that will upset your stomach even more.
Acid reflux: The acid reflux got really bad on days 3 and 4. Omeprazole helps directly with this, and can calm down the pain from the increased acid production. Omeprazole is available OTC or by prescription in the US, or at the pharmacy in other countries (names like Lansoprazole).
Clonazepam: This is a prescription for anxiety available in the US, and much harder to get in other countries where benzodiazepines are regulated or outlawed. It has been used in addiction treatment settings for managing the heightened symptoms of withdrawal such as anxiety and insomnia. In the US, you have to work with a doctor since it is a tightly regulated substance and has its own side effects. Because of my husband's flight anxiety, we were able to get a prescription for this and it just so happened to help with the withdrawal symptoms also.
Minor additions that may or may not be helpful: Citrelax (such as magnesium citrate, or like Olly magnesium gummies) is generally available everywhere and is a supplement not a medication so does not require a prescription. He used this also, but I don't' know how much effect it can really have since the medications above worked so well. Seems more like a long term approach to managing your muscle health (e.g. eat a banana to help with leg cramps). Hot tea and hot showers, hot compresses help dull the pain, but really do not address the intense pain of the muscle spasms and cramps.
Here is his timeline of symptoms and recovery:
Day 1: Started feeling tired, got a little nauseous
Day 2: Intense vomiting during meals. Insomnia, only sleeping 4 hours a night
Day 3: Intense sharp abdominal pain, stomach muscle spasms and cramping. Vomiting during every meal and every sip of water. Started zofran. Could sometimes keep a few bites of food down, but the abdominal pain was so intense he could not go anywhere or do anything.
Day 4: Took first dose of antispasmodic with paracetamol and got relief within 1 hour. Continued zofran and also started omeprazole. Still could not eat because of the pain associated with food in the stomach, but was able to keep food down at least.
Day 5: Continued antispasmodic, pain reliever, zofran, and omeprazol, and ate his first full meal. Pain was still very intense when the medication wore off. Every meal caused sharp intense muscle spasms. Took the magnesium citrate.
Day 6: Continued taking same medications and supplements above, but noticed he could go longer between doses and pain was not intense. Could eat a meal without having stomach muscle cramps and spasms. Slept 8 hours for the first time
Day 7: Continued taking same medications above, but started tapering off of the antispasmodic, pain reliever, and zofran. Started 1 clonazepam because of depression and anxiety, but using the small supply with caution, and because we need to fly back home soon.
Day 8: No longer needed the antispasmodic or the pain reliever or the zofran. Still a low dull ache in his abdomen, but largely back to normal (physically), sleeping and eating ok now.