Actually the Philippines is the only SE Asian nation without heroin. In the late 1960s and early 70s there was a fair amount of heroin (#3) in the Metro Manila area. Eventually the market was consolidated by 1 man, an ethnic-Chinese (Tsinoy as they are known in the Philippines) named Lim Seng.
Seng was 1 of 4 local men who would produce #3 locally, buying morphine from ethnic-Chinese in Thailand. Eventually he also began manufacturing #4 for export and that was his downfall. Seng began exporting so much #4 that he was able to undersell his 3 competitors who soon went out of business leaving Lim Seng holding a monopoly not only on the export market, but on the Manila #3 market as well. Monopolies are dangerous for everyone.
2 American Airmen were hopping a flight to Okinawa and were arrested in the pre-flight search at Clark Airbase (north of Manila)with 4 ounces of pure #4. Naturally they gave up their connection and as those things go it led up the line to Seng. The Philippines even now has a symbiotic political relationship with America. In the Vietnam Era though it was practically an American colony and so looking for a good whipping boy over the wave of military addictions the US bore down on Philippine dictator Ferdinand Marcos.
With only a single distributor in the entire city, the only Philippine city with a street scene, it took only a couple of months for the entire local market to collapse. Then, ignoring petty dealers the government went after addicts who had turned to pharmaceutical opiates and opioids. Locking thousands of addicts up in mental hospital type re-education camps the Philippine Government simultaneously took aim at its own pharmacopiea.
By 1975 even codeine had been removed from the market. Imagine a nation that gives terminal cancer patients anti-psychotic medication to try and assuage their excruciating pain. Though Marcos was gone by 1986 the newly-Democratic nation had far too many problems on its hands to even consider trying to tackle the lack of pain relief.
Ironically it was that 14 years without illicit drugs that led to the country's present problem with smokable methamphetamine, called "Shabu" (Japanese slang meaning "Go Fast") locally. Addiction in most Filipinos' minds was tied to opiates/opioids and so they came like lambs to the slaughter.
By the early 1990s the World Health Organisation,or "WHO," became increasingly concerned with the nation's lack of opiates/opioids and began lobbying for their re-inclusion in the pharmacopiea. With more than 20 years without them the country was convinced that it didn't need them. However, as is so often the case, the desire for increased Aid led the Philippine Government to temper its attitude if ever so slightly.
It agreed, under duress, to introduce the opioid nabulphine hcl. into the pharmocopiea under the brand name "Nubain." Nabulphine is considered practically useless by the Western World, so much so in fact that it is not even a Scheduled Substance in the US, placed below even codeine combination medications like codeine/APAP, etc.
While it was progress it wasn't sufficient for the WHO and so it ended up actually taking the Philippine Government to court on the issue though the case was averted, after nearly a decade of haggling, with a Settlement that allowed for the re-introduction of substantiative opiates/opioids. Interestingly the Settlement still barred moderate opiates/opioids like codeine, dihydrocodeine and dihydrocodeinone (hydrocodone) while allowing morphine, oxycodone and fentanyl.
The WHO has what is known as the, "3 Rung Pain Ladder." Pain, according to WHO Guidelines is to be treated in the following manner:
Rung I: Non-opiate/opioid analgesics like APAP, Motrin and aspirin and non-steroidals.
Rung II: Non-steroidals together with combination opiate/opioids like APAP with codeine or moderate opiates/opioids like codeine on its own.
Rung III: Heavy opiates/opioids like hydromorphone, oxycodone, fentanyl, morphone and so on.
The Philippines, ever terrified of opiate/opioid addiction agreed to a novel solution. It would institute a modified Pain Ladder. Instead of the 3 Rung it would implement a 2 Rung with Rung I and III. The patient would graduate from Motrin to morphine.
In agreeing to this novel, somewhat insane solution the Government also revamped its prescription system. Now all Controlled Substances, known locally as, "Dangerous Drugs," would require an S2 Prescription. Only physicians undergoing a more rigorous liscencure from the "Bureau of Dangerous Drugs" can administer an S2 Prescription. To date only 18% of physicians bother to even apply for the liscence.
As if that isn't dismal enough, there is the issue of availability. The Philippines is a nation of 7,107 islands. Most islands do not stock the 4 approved opiates/opiates (pethedine/meperidine, oxycodone, fentanyl and morphine). Those that do have very limited stocks. Outside of certain hospitals only a single retail chain stocks them and then only in designated stores. The designated stores are allowed only a maximum amount of stock (for example, with morphine it is 3 boxes of tablets, each box containing 100 tablets). However they usually stock only 1 box because store managers are personally responsible if they stock medications that don't sell within certain periods of time.
Pricing is also an issue. Only morphine is produced domestically and is still far above what most can afford. There is no national minimum wage but an avverage labourer makes 5 US Dollars a day. He would have to work 2 weeks straight to buy a box of morphine. Most prefer to feed their children. Because one can rarely afford to buy it, it doesn't make sense to stock it and so it becomes a circuitous problem.
In terms of a new street trade having developed...Ironically the Philippines is the only nation on the planet with a street scene entirely revolving around nabulphine! Even then it is only in 2 neighbourhoods of a single city (Cebu City). Because nabulphine is only injectable there is a 98% prevalence of HIV and 100% of HCV (Hep C). Because of poverty dosages are sold by placing each user's syringe into a single ampoule.
There is a fair amount of heroin transhipment, especially by West Africans but they just haven't cared to branch off into local sales. My initial guess was poverty but Indonesia is poorer and the Africans there were able to develop a huge domestic market (if only in Jakarta). Still, I reckon sooner or later someone will try it in Cebu City and then all bets are off.
Alternatively it could take place like the transition into cocaine. A Chinese freighter dumped more than a tonne of cocaine in kilo packages into the sea as a joint Chinese-Philippine counter narcotic operation took place last year. Ever since cocaine has taken hold. People are still fishing kilos hahaha.