Dihydrocodeine, Aspirin and Caffeine

Drug Class: Dihydrocodeine, Aspirin And Caffeine > Dihydrocodeine > Ethers Of Morphine > Semi Synthetic Opioid > Opioids > Opioid Agonist > Analgesic.


Preparations containing dihydrocodeine bitartrate, aspirin and caffeine relieve moderate to moderately severe pain.

Other, off label uses for this medicine

One ingredient in this combination drug suppresses cough while another reduces body temperature. Someone could use dihydrocodeine bitartrate, aspirin and caffeine preparations to treat a condition causing pain, a fever and a nagging cough.

General Drug Information

Dihydrocodeine bitartrate, aspirin and caffeine is a generic combination sometimes sold under the brand name Synalgos-DC.

Dihydrocodeine bitartrate is an opioid analgesic, sometimes called a narcotic pain reliever. Aspirin is a non-opioid analgesic. Caffeine is a stimulant, included in this preparation to counteract sleepiness associated with opioid use.


Physicians will prescribe an initial dose of dihydrocodeine bitartrate, aspirin and caffeine products based on the severity of the patient’s pain and adjust dosage according to the patient’s response to treatment for that pain.

The typical dosage for adults is two capsules every four hours as needed to control pain. Products containing dihydrocodeine bitartrate, aspirin and caffeine are not appropriate for children.


Dihydrocodeine bitartrate, aspirin and caffeine act in different ways to relieve symptoms. The body absorbs these chemicals through the gastrointestinal tract. The liver metabolizes dihydrocodeine, aspirin and caffeine, breaking these chemicals down into various metabolites; urine carries most of the metabolites from the body.

Dihydrocodeine depresses the central nervous system, or CNS, to dull the brain’s perception of pain. Other CNS effects include sedation, relaxation and a pleasant feeling of euphoria.

Dihydrocodeine depresses cough reflex and respiratory centers in the brain to suppress cough and cause slow, shallow and irregular breathing patterns. Opioids like dihydrocodeine increase the tone of smooth muscle groups, including the intestinal muscles responsible for pushing stool through the digestive tract. Dihydrocodeine and other opioids cause vasodilation, widening blood vessels enough to lower blood pressure.

Aspirin works by inhibiting the production of prostaglandins, chemicals responsible for sending pain messages to the brain. Aspirin accomplishes this by decreasing COX enzymes, which do many jobs in the body including producing prostaglandins and causing platelets to stick together. Aspirin also works on the brain’s temperature-regulating center, the hypothalamus.

Caffeine is a stimulant that works by decreasing the production of adenosine, a chemical that promotes sleep.


Patients with peptic ulcer or clotting disorders resulting in bleeding problems should not use aspirin.

Long-term dihydrocodeine use, especially at high doses, may cause the consumer to become opioid-dependent and suffer withdrawal symptoms when he discontinues this medication abruptly.

Using dihydrocodeine products with other CNS depressants enhances the depressive effects of these drugs. Examples of other substances that depress the nervous system are alcohol, other opioids, sedatives or tranquilizers, muscle relaxants, general anesthetics, and some anti-vomiting and anti-psychotic drugs. When a patient needs both dihydrocodeine and the other CNS depressant, physicians should reduce the dosage of one or both drugs.


Preparations containing dihydrocodeine bitartrate, aspirin and caffeine may make the consumer feel dizzy or drowsy, or impair his physical and mental performance. Alcohol and some other medications enhance these effects. Consumers should not drive a car or operate heavy machinery until they know how this combination drug affects them.


People who are hypersensitive to the effects of dihydrocodeine bitartrate, aspirin, caffeine or any ingredient in the preparation should not use that drug.

Pregnancy, Labor and Delivery, Breastfeeding

Medical research has not yet established the harm dihydrocodeine bitartrate, aspirin and caffeine may pose to a pregnant woman, an unborn child or the reproductive capabilities in males or females. Small amounts of dihydrocodeine bitartrate, aspirin and caffeine may pass into human milk and onto a nursing baby; women should not breastfeed while using this combination drug.

Drug Interactions

Dihydrocodeine bitartrate, aspirin and caffeine preparations can interact with other medications in unsafe or unwanted ways. Consumers should supply a list of all medications, including over-the-counter drugs, vitamins and herbal remedies, to their physicians.

Aspirin can enhance the effects of some anticoagulants used to prevent blood clots.

Side effects

The most frequently reported side effects are lightheadedness, dizziness, drowsiness, sedation, nausea and vomiting, constipation, itching and skin rashes.


Nearly 15,000 Americans lose their lives every year due to overdose of prescription painkillers, including dihydrocodeine. A person who has taken an overdose of a combination drug containing dihydrocodeine bitartrate, aspirin and caffeine needs immediate medical care.

Emergency room personnel will establish an airway or place the patient on a ventilator to help him breathe. Nurses will start intravenous fluids to stabilize blood pressure and may pump excess medication from the patient’s stomach. Physicians may administer drugs to reduce dihydrocodeine levels if the patient shows signs of breathing problems.


Recreational drug abusers target dihydrocodeine preparations because of the euphoria opioids produce. The DEA categorizes dihydrocodeine bitartrate, aspirin and caffeine combination products as class III drugs, meaning the pose the same potential for abuse as Tylenol with codeine or the muscle building drugs, anabolic steroids. To reduce the risk for recreational abuse, dihydrocodeine bitartrate, aspirin and caffeine products are available only with a prescription.

Recreational drug abuse increases the consumer’s risk for side effects, overdose, addiction and physical dependence resulting in withdrawal symptoms.


An opioid-dependent person will experience withdrawal symptoms a few hours after his last dose of dihydrocodeine; these symptoms will continue for five or more days. To avoid withdrawal symptoms, physicians recommend tapering dihydrocodeine use slowly over the course of a few days. While tapering works for many individuals, overpowering and persistent withdrawal symptoms prevent some people from quitting opioids at the appropriate time.


Some local healthcare institutions now offer detoxification services, in which physicians administer drugs to lower dihydrocodeine levels along with medications to ease withdrawal symptoms.

Many informed consumers now choose rapid detox, a more humane and efficient form of detoxification. During rapid detox, patients receive sedatives and anesthesia before the standard detoxification and anti-withdrawal drugs so that they rest in a comfortable “twilight sleep” during the procedure.


Dihydrocodeine bitartrate, aspirin and caffeine combination products are best stored at 77 degrees Fahrenheit in a tightly sealed container. All medications should be stored out of the reach of children.