Tramadol and (Dextro)Propoxyphene (Darvon, Darvocet the kind with Acetaminophen/Paracetamol added to them) are Mu agonists not Kappa Agonists if i remember right. Tramadol's active metabolite O-desmethyltramadol does have a higher affinity for both the Delta and Kappa receptors then Tramadol does but it still acts primarily as a Mu agonist i believe. This is in addition to Tramadol acting as a SNRI which is what i mostly seem to get from the junk. (Dextro)Propoxyphene has been taken off the market for a few years in most of the world because of it's very toxic effects that have nothing to do with it's very mild Opioid effects. It is primarily a Mu agonist with very weak action on that site.
Butorphanol on the other hand exerts most of it's analgesic effects through it's Kappa agonist as it is a mixed antagonist/agonist effects on the Mu receptor. It's still used abit in the form of a nasal spray for migraines (it's long since gone generic here and they no longer have brand name Stadol in Canada) but unless your doctor for some reason prefers to use this drug (some doctors are just comfortable prescribing what they know and have been using for awile) or if the more commonly used Mu agonist drugs such as Codeine, Demerol (meperidine/Pethidine), oxycodone, etc don't work or aren't tolerated by the patient other Opioids like Codeine, Fiorinal-C's/Fioricet-C's (Aspirin or Acetaminophen/Paracetamol with Butalbital, caffeine and Codeine) Oxycodone or Demerol (which although it's fallen out of favor is still used for a few purposes one of which is migraines) is preferred or even Morphine usually with a anti-emetic for acute relief. Here if you show up puking from a Migraine they will usually give you a shot of Demerol with a anti-emetic such as Dimenhydrinate or Prochlorperazine or even Chlorpromazine. If they are feeling really generous they will give you Morphine with a anti-emetic. I do know one person who was prescribed Talwin for migraines but i am going to bet this is because their doctor has been around for ages and for some reason prefers Talwin over more common Opioids for treating migraine like headaches.
Drugs like Pentazocine, Butophanol, and Nalbuphine are REAL Opioid's they just don't have typical opiate effects like Morphine and other Mu agonists due to their affinity for the Kappa receptor. Kappa Opioid's do work well for some people and for some reason work better in women and red heads in particular. They have fallen out of favor among most doctors because of the side effects of dysphoria and sometimes hallucinations and also because they tend not to be great analgesics and also because you can't use them in patients who are dependent on Mu agonist Opioids. Talwin was popular in some places in the T's and blues combo where they mixed the anti-histamine tripelennamine with Talwin and injected the combo. Another popular combo in certain places like the Canadian prairies and other parts where it can be hard to get Heroin or decent script Opioids was T's and R's which is Talwin mixed with Ritalin. This was usually injected for a sort of poor mans speedball though i seriously doubt combing Talwin with a shitty stimulant like Methylphenidate would produce effects anywhere near as good as say a Heroin and Coke or Dilaudid or Morphine and Coke speedball. Of course you can't inject any Talwin pills made in the US as they are all Talwin NX which have Naloxone in them. They never did add Narcan to Talwin in Canada as i doubt it was popular except in a few small isolated towns. I have never seen it anywhere though my ex did call me up the night she took abunch of Talwin pills orally and she sounded like she was having a good time. She was not tolerant to Opioid's at all at the time and described Pentazocine as being alot more spacey, dreamlike and disorienting then Oxycodone was. She liked it alot but had she actually been addicted to Opioids she would have been driven right into precipitated withdrawal the same as you would be with other mixed antagonists/agonists.
