About Dihydrocodeine:

• Dihydrocodeine is an opiate painkiller. It's used to treat moderate to severe pain, such as after an operation or a serious injury.
• It's also used for long-standing pain when weaker painkillers, such as paracetamol, ibuprofen and aspirin, have not worked.
• Dihydrocodeine is only available on prescription. It also comes mixed with paracetamol, this is called co-dydramol.
• It comes as standard tablets, slow-release tablets and as a liquid that you swallow. It can also be given by an injection into the muscle or under the skin. This is usually done in hospital.
• Dihydrocodeine is also known by the brand names
  • DHC Continus
  • DF118 Forte

As well as blocking pain signals, dihydrocodeine can have negative effects. Your breathing may become slow and shallow. It may also slow down your digestion, which is why dihydrocodeine can cause constipation.

Key Facts:

• Dihydrocodeine works by stopping pain signals travelling along the nerves to the brain.
• Standard dihydrocodeine tablets take 1.5 to 2 hours to work fully.
• It's possible to become addicted to dihydrocodeine, but this is rare if you're taking it to relieve pain and you're taking it as a doctor has prescribed.
• Dihydrocodeine can cause withdrawal problems. Do not stop taking the medicine suddenly.
• The most common side effects are feeling or being sick, feeling drowsy or constipation.

How much will I take?

• Adults and children aged 4 years and over can take dihydrocodeine.
• Dihydrocodeine tablets come in 5 different strengths. The tablets contain 30mg, 40mg, 60mg, 90mg or 120mg of dihydrocodeine.
• Dihydrocodeine liquid is fast-acting and takes around 30 to 60 minutes to work.
• Standard tablets take between 1.5 and 2 hours to work fully.
• Slow-acting tablets may take a little longer to work, but will last longer.

It is safe to take dihydrocodeine for long-term conditions, but your body can get used to it, which means it stops working as well at reducing pain. Do not increase the dose if this happens. Talk to a doctor, who might prescribe you a different strength or a different painkiller.

Dihydrocodeine:
https://www.nhs.uk/medicines/dihydrocodeine/

Dihydrocodeine is an opioid analgesic used as an alternative or adjunct to codeine to treat moderate to severe pain, severe dyspnea, and cough. It is semi-synthetic, and was developed in Germany in 1908 during an international search to find a more effective antitussive agent to help reduce the spread of airborne infectious diseases such as tuburculosis. It was marketed in 1911. Dihydrocodeine is metabolized to dihydromorphine - a highly active metabolite with a high affinity for mu opioid receptors. Dihydrocodeine is used for the treatment of moderate to severe pain, including post-operative and dental pain. It can also be used to treat chronic pain, breathlessness and coughing. In heroin addicts, dihydrocodeine has been used as a substitute drug, in doses up to 2500mg/day to treat addiction.

Dihydrocodeine:
https://drugs.ncats.io/drug/N9I9HDB855

While nowhere near as "popular" as oxycodone or Vicodin, dihydrocodeine appears in more than a few prescription-based opiate drugs. Dihydrocodeine produces pain-relieving effects along the lines of codeine and works well for treating a range pain-related conditions.

This drug's pain-relief properties also come with a risk for abuse and addiction, regardless of whether its used for medicinal or recreational purposes. While effective as a treatment drug, a developing drug abuse problem may well require some form of dihydrocodeine addiction treatment when left to its own devices. Dihydrocodeine produces short-acting, rapid onset effects. As a member of the codeine family, dihydrocodeine acts as a main ingredient in several types of prescription opiate drugs.

Rising tolerance levels will continue for as long as a person keeps using the drug.

Dihydrocodeine's ability to slow chemical activities throughout the brain and central nervous system inevitably slows down the body's major systems. In large enough dosage amounts, dihydrocodeine can overpower the brain's ability to maintain one or more systems. When this happens, bodily functions shutdown altogether. These conditions can bring on an overdose episode. More often than not, the body's respiratory system is the first to be affected. Someone having difficulty breathing or experiencing slowed breathing rates may well be overdosing on the drug. These conditions can quickly lead to death and warrant immediate medical attention.

According to the British Journal of Clinical Pharmacology, in doses of up to 2,500 milligrams, dihydrocodeine can also be used as a replacement therapy to treat cases of chronic heroin addiction. Replacement therapies help to wean addicts off heroin while relieving uncomfortable withdrawal aftereffects.

Excerpt from opiate.com:
https://www.opiate.com/dihydrocodeine/

It's most commonly prescribed for the treatment of mild to moderate pain. Dihydrocodeine is also effective at reducing coughing and pain associated with shortness of breath. Several formulas of dihydrocodeine exist that combine it with over-the-counter pain relievers such as acetaminophen, ibuprofen, and aspirin. Caffeine is included in select formulas. Formulas such as these are manufactured specifically for pain reduction. Select dihydrocodeine products include antihistamines. Antihistamines can reduce side effects like itchiness and flushed skin that are common with dihydrocodeine and codeine use.

Dihydrocodeine is roughly twice as powerful as codeine. Dihydrocodeine misuse and abuse is a contributing factor to the opioid overdose epidemic that began in the late 1990s and has continued through to today. Dihydrocodeine is often abused recreationally due to the euphoric high that can result from using high doses of the drug. The high end of a standard dihydrocodeine dose is 30 mg for immediate-release oral tablets. People who abuse the drug recreationally often take between 70 mg to 500 mg at one time in order to achieve the desired effects.

Dihydrocodeine is well absorbed when taken orally, reaching peak plasma levels within two hours of ingestion. The mean elimination half-life of dihydrocodeine is four hours. Roughly 90% of the drug and its metabolites are eliminated from the body within the first 24 hours. The remaining 10% remains at testable levels in the body for up to four days.

Excerpt from The Recovery Village:
https://www.therecoveryvillage.com/dihydrocodeine-addiction/how-long-stay-in-system/

I'd say DHC is 1-3x stronger than Codeine at pain relief as it truly depends on the persons CYP2D6. For some people codeine works fine, for some it doesn't seem to work at all unless taken in larger doses. DHC also feels like it lasts longer, because it's physical and mental euphoria is so strong there seems to be a very long period after the pain properties wear off that the user still feels the drug. Even if taken in medical doses.

DHC is commonly prescribed in the UK, In Scotland especially. It is also commonly misused and abused in the UK as a result of it being prescribed as a safe alternative to morphine and other medications that the NHS will rarely prescribe. This lack of stigma is what leads your normal working class British people to start misusing their pain medication.

Recreationally DHC is one of the closest oral opioids to Heroin in terms of effects. Euphoria and sedation is unlike any other oral opioid. Part of DHC's introduction to the UK was to be used for getting Heroin users off heroin. Because it is so euphoric, it is very easy and also worryingly common for non chronic patients to misuse their medication.

A Reddit Discussion:
https://www.reddit.com/r/Dihydrocodeine/comments/bklfve/benefits_of_dhc/

Dihydrocodeine

Duration: A weak semi-synthetic opioid analgesic and antitussive (anti-cough) drug. Often sold as a syrup in combination with aspirin or paracetamol. Not to be confused with the slightly less potent codeine.
Route	Onset	Duration	After Effects
Tripsit Factsheets
Dihydrocodeine Basic Information: http://drugs.tripsit.me/dihydrocodeine
All ROAs:	30-45 minutes	3-4 hours	1-8 hours
Aliases: dhc
Effects: Euphoria, Dry Mouth, Mood lift, Itchiness, Relaxant, Constipation, Pupil constriction, Analgesia.

Pediatric:
Appropriate studies have not been performed on the relationship of age to the effects of Trezix in the pediatric population. It should not be used in children 12 years of age or younger. Safety and efficacy have not been established.

Trezix should not be used to relieve pain after surgery removal of tonsils or adenoids in any children. Severe breathing problems and deaths have been reported in some children who received codeine after tonsil or adenoid surgery.

Geriatric:
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of acetaminophen, caffeine, and dihydrocodeine combination in the elderly. However, elderly patients are more likely to have age-related lung, liver, kidney, or heart problems, which may require caution and an adjustment in the dose for patients receiving acetaminophen, caffeine, and dihydrocodeine combination in order to avoid potentially serious side effects.

Other Interactions:

• Cabbage
• Ethanol
• Grapefruit Juice
• Tobacco

Other Medical Problems:
Make sure you tell your doctor if you have any other medical problems, especially:

• Addison's disease (adrenal gland problem)
• Alcohol abuse, or history of
• Brain tumor, history of
• Breathing or lung problems (eg, COPD, sleep apnea, respiratory depression)
• Cor pulmonale (serious heart condition)
• Depression, history of
• Drug dependence, especially with narcotics, or history of
• Enlarged prostate (BPH, prostatic hypertrophy)
• Head injuries, history of
• Hypothyroidism (an underactive thyroid)
• Increased pressure in the head
• Mental health problems, history of
• Obesity (overweight)
• Problems with passing urine
• Weakened physical condition - Use with caution. May increase risk for more serious side effects

• Hypotension (low blood pressure)
• Pancreatitis (inflammation of the pancreas)
• Seizures, history of - Use with caution. May make these conditions worse

• Kidney disease
• Liver disease - Use with caution. The effects may be increased because of slower removal of the medicine from the body

• Lung breathing problems (eg, asthma, respiratory depression), severe
• Stomach or bowel blockage (including paralytic ileus) - Should not be used in patients with these conditions

Acetaminophen, Caffeine, And Dihydrocodeine (Oral Route) (Panlor-DC | Panlor-SS | Trezix | Zerlor):
https://www.mayoclinic.org/drugs-supplements/acetaminophen-caffeine-and-dihydrocodeine-oral-route/description/drg-20406132

Breastfeeding:

Summary of Use During Lactation:

Maternal use of oral narcotics during breastfeeding can cause infant drowsiness, central nervous system (CNS) depression and even death.

Like codeine, pharmacogenetics probably plays a role in the extent of CNS depression.

Newborn infants seem to be particularly sensitive to the effects of even small dosages of narcotic analgesics. Dihydrocodeine possibly caused severe respiratory depression in one newborn infant whose mother was taking the drug for cough. Once the mother's milk comes in, it is best to provide pain control with a nonnarcotic analgesic and limit maternal intake of hydromorphone to a few days at a low dosage with close infant monitoring.

If the baby shows signs of increased sleepiness (more than usual), difficulty breastfeeding, breathing difficulties, or limpness, a physician should be contacted immediately.

Because there is little published experience with dihydrocodine during breastfeeding, an alternate drug may be preferred, especially while nursing a newborn or preterm infant.

Effects on Lactation and Breastmilk:

Narcotics can increase serum prolactin.

However, the prolactin level in a mother with established lactation may not affect her ability to breastfeed.

Alternate Drugs to Consider:

• (Analgesia) Acetaminophen
• Butorphanol
• Hydromorphone
• Ibuprofen
• Morphine
• (Antitussive) Dextromethorphan

Dihydrocodeine Drug Levels and Effects:
https://www.ncbi.nlm.nih.gov/books/NBK500692/

Experiences with Dihydrocodeine
Forum (142 posts):
https://healthunlocked.com/dihydrocodeine

Erowid Experience Vault:
https://erowid.org/experiences/subs/exp_Pharms_Dihydrocodeine.shtml

Electronic Medicines Compendium Dihydrocodeine Package Leaflet (PDF 2 pages):
https://www.medicines.org.uk/emc/files/pil.5784.pdf

mhra.gov.uk Dihydrocodeine Package Leaflet:
http://www.mhra.gov.uk/home/groups/spcpil/documents/spcpil/con1504759191153.pdf

Mallinckrodt Pharmaceuticals Parzone Spec Sheet (PDF 1 page):
http://www.mallinckrodt.com/globalassets/documents/products/controlled-substances/specsheet-1578.pdf

Drugs.com Dihydrocodeine Tablets Package Leaflet:
https://www.drugs.com/uk/dihydrocodeine-30mg-tablets-leaflet.html

Kaiser Permanente Panlor SS - Trezix:
https://healthy.kaiserpermanente.org/health-wellness/drug-encyclopedia/drug.acetaminophen-320-5-mg-caffeine-30-mg-dihydrocodeine-16-mg-capsule.583307?kpSearch=panlor

Webmd Panlor:
https://www.webmd.com/drugs/2/drug-174805/panlor-acetaminophen-caffeine-dihydrocodeine-oral/details

New Zealand DHS Continus Data Sheet (PDF 9 pages):
https://medsafe.govt.nz/Profs/Datasheet/d/DHCContinustab.pdf

Brand Names:
Drocode, Paracodeine, Parzone, Rikodeine, Trezix, Synalgos DC, Panlor DC, Panlor SS, Contugesic, New Bron Solution-ACE, Huscode, Drocode, Paracodin, Paramol (UK), Codidol, Dehace, DHC Continus, Didor Continus, Dicogesic, Codhydrine, Dekacodin, DH-Codeine, Didrate, Dihydrin, Hydrocodin, Nadeine, Novicodin, Rapacodin, Fortuss, Remedeine, Dico, Synalgos-DC (US), and DF-118.

Dihydrocodeine is used as an alternative to codeine. It was first described in 1911 and approved for medical use in 1948. It was developed during the search for more effective cough medication, especially to help reduce the spread of tuberculosis, pertussis, and pneumonia in the years from 1895 to 1915.

Adding a non-opiate pain reliever helps to enhance the effects of dihydrocodeine without increasing the opiate concentration.

Synalgos-DC is a combination prescription medication used to treat moderate to severe pain. It has three active ingredients: dihydrocodeine (a narcotic), aspirin and caffeine. All three drugs ease pain, and caffeine also counteracts the drowsiness common with dihydrocodeine. Because of its potency, this drug is considered a high-alert medicine by the Institute for Safe Medication Practices and should be taken exactly as your doctor prescribes.

Excerpt from Share Care:
https://www.sharecare.com/health/analgesic-pain-relief/what-synalgos-dc-used

FDA Synalgos-DC (PDF 3 pages):
https://www.accessdata.fda.gov/drugsatfda_docs/label/2013/011483s027lbl.pdf

FDA Synalgos-DC (PDF 27 pages):
https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/011483s030lbl.pdf

Webmd Synalgos-DC:
https://www.webmd.com/drugs/2/drug-3419/synalgos-dc-oral/details

What is the most important information I should know about Synalgos-DC??

• Dihydrocodeine can slow or stop your breathing, and may be habit-forming.
• MISUSE OF THIS MEDICINE CAN CAUSE ADDICTION, OVERDOSE, OR DEATH, especially in a child or other person using the medicine without a prescription.
• This medicine is not for use in anyone under 18.
• Taking this medicine during pregnancy may cause life-threatening withdrawal symptoms in the newborn.
• Fatal side effects can occur if you use this medicine with alcohol, or with other drugs that cause drowsiness or slow your breathing.

Synalgos DC (aspirin, caffeine, and dihydrocodeine bitartrate capsules, usp)

Side Effects:
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
RxList
rxlist.com Synalgos-DC Information: https://www.rxlist.com/synalgos-dc-drug/patient-images-side-effects.htm
Opioid medicine can slow or stop your breathing, and death may occur. A person caring for you should seek emergency medical attention if you have slow breathing with long pauses, blue colored lips, or if you are hard to wake up.
Aspirin may cause stomach or intestinal bleeding, which can be fatal. This can occur without warning while you are taking this medicine.
Call your doctor at once if you have: noisy breathing, sighing, shallow breathing, breathing that stops during sleep a light-headed feeling, like you might pass out little or no urination symptoms of stomach bleeding - bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds low cortisol levels - nausea, vomiting, loss of appetite, dizziness, worsening tiredness or weakness
Seek medical attention right away if you have symptoms of serotonin syndrome, such as: agitation, hallucinations, fever, sweating, shivering, fast heart rate, muscle stiffness, twitching, loss of coordination, nausea, vomiting, or diarrhea.
Serious side effects may be more likely in older adults and those who are overweight, malnourished, or debilitated.
Long-term use of opioid medication may affect fertility (ability to have children) in men or women. It is not known whether opioid effects on fertility are permanent.
Common side effects may include: dizziness, drowsiness nausea, vomiting, constipation itching, mild rash
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Pediatric:
Use of aspirin, caffeine, and dihydrocodeine combination is not recommended in children 12 years of age or younger.

Synalgos DC should not be used to relieve pain after surgery removal of tonsils or adenoids in children. Severe breathing problems and deaths have been reported in some children who received codeine after tonsil or adenoid surgery.

Geriatric:
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of aspirin, caffeine, and dihydrocodeine combination in the elderly. However, elderly patients are more likely to have age-related lung, liver, kidney, or heart problems, which may require caution and an adjustment in the dose for patients receiving aspirin, caffeine, and dihydrocodeine combination in order to avoid potentially serious side effects.

Other Interactions:

• Ethanol
• Grapefruit Juice
• Tobacco

Other Medical Problems:
Make sure you tell your doctor if you have any other medical problems, especially:

• Alcohol abuse, or history of
• Brain problems (eg, tumor, increased intracranial pressure), history of
• Breathing or lung problems (eg, COPD, sleep apnea, respiratory depression)
• Cor pulmonale (serious heart condition)
• Depression, history of
• Drug dependence, especially with narcotic abuse or dependence, or history of
• Head injuries, history of
• Hyperkalemia (high potassium levels in the blood)
• Hypovolemia (low blood volume)
• Mental health problems, history of
• Obesity (overweight)
• Weakened physical condition - Use with caution. May increase risk for more serious side effects

• Bleeding problems
• Hypotension (low blood pressure)
• Pancreatitis swelling of the pancreas)
• Peptic ulcer disease, active or history of
• Seizures, history of - Use with caution. May make these conditions worse

• Hemophilia (bleeding problem)
• Reye's syndrome
• Severe asthma, asthma with nasal polyps and runny nose, trouble breathing, or other lung problems
• Stomach or bowel blockage (including paralytic ileus)
• Surgery (eg, nasopharyngeal tonsils, tonsils) - Should not be used in patients with these conditions

• Kidney disease
• Liver disease - Use with caution. The effects may be increased because of slower removal of the medicine from the body

Aspirin, Caffeine, and Dihydrocodeine (Oral Route) (Synalgos-DC):
https://www.mayoclinic.org/drugs-supplements/aspirin-caffeine-and-dihydrocodeine-oral-route/description/drg-20095195

Cophene-S
This combination product is used to treat symptoms caused by the common cold, flu, allergies, hay fever, or other breathing illnesses (e.g., sinusitis, bronchitis). Decongestants help relieve stuffy nose symptoms. This product also contains an opioid cough suppressant (antitussive) that affects a certain part of the brain, reducing the urge to cough. Antihistamines relieve watery eyes, itchy eyes/nose/throat, runny nose, and sneezing. Cough-and-cold products do not cure colds. Cough due to a common cold often does not need to be treated with medicine.

Do not increase your dose or use this product more often or for longer than directed. Your condition will not improve any faster, and your risk of side effects will increase.

This medication may cause withdrawal reactions, especially if it has been used regularly for a long time (more than a few weeks) or in high doses.

Excerpt from Webmd:
https://www.webmd.com/drugs/2/drug-55182/cophene-s-oral/details