Dihydrocodeine, Phenylephrine, and Guaifenesin

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


People use dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin combination drugs to relieve a dry, unproductive cough and congestion caused by upper respiratory tract infections, like the common cold.

General Drug Information

Laser Pharmaceuticals LLC combines dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin in the grape-flavored brand name preparation, Donatuss. Each 5 mL teaspoon of Donatuss contains 7.5 mg of dihydrocodeine bitartrate, 7.5 mg of phenylephrine hydrochloride and 50 mg of guaifenesin.

Dihydrocodeine is an opioid drug, sometimes called a narcotic analgesic. Phenylephrine is a decongestant and guaifenesin is an expectorant.


Physicians will prescribe initial doses of dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin products based on the severity of the patient’s symptoms and adjust the dosage according to the patient’s response to treatment.

The typical dose for a brand name preparation is one or two 5 mL teaspoonfuls every four to six hours as needed to control cough and congestion in adults and children over the age of 12 years. Pediatricians typically prescribe one-half to one 5 mL teaspoonful every four to six hours to relieve symptoms in children ages 6 - 12 years. Physicians may prescribe lower doses to elderly patients, as these consumers may be more sensitive to the effects of dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin preparations.

The maximum daily dose for adults and children 12 years of age and older is 90 mg of dihydrocodeine, 90 mg of phenylephrine or 600 mg of guaifenesin. Children age 6 - 12 should not take more than 45 mg of dihydrocodeine, 45 mg of phenylephrine or 300 mg of guaifenesin in any 24-hour period.

Administrators should use an approved measuring device when dispensing dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin. Using a household teaspoon may result in inadequate doses or dangerous overdoses.


Dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin work in different ways to relieve cough and congestion.

Dihydrocodeine is cough suppressant, sometimes called an antitussive. It acts on the cough reflex center in the brain, the medulla, to suppress the urge to cough. Dihydrocodeine depresses other respiratory centers in the brain to cause slow, shallow and irregular breathing patterns.

In other actions, dihydrocodeine depresses the central nervous system to dull the brain’s perception of pain. Other central nervous system, or CNS, effects include sedation, relaxation and a pleasant sense of euphoria. Dihydrocodeine increases the tone of smooth muscles, like intestinal muscles that move stool through the digestive tract, to stiffen these muscles and make them less functional. Opioids like dihydrocodeine widen blood vessels; this vasodilation lowers blood pressure.

When a person begins opioid treatments, he is “opioid-naïve” and sensitive to the effects of dihydrocodeine. With continued use, he becomes tolerant to the effects of opioids. An opioid-tolerant person needs larger doses of dihydrocodeine more often to achieve the same effects.

Phenylephrine hydrochloride is a decongestant that works by shrinking blood vessels in the nasal passages, allowing more room for air to flow through the nose.

Guaifenesin is an expectorant that thins secretions to make it easier to cough phlegm and mucus from the lungs and breathing passages. Guaifenesin increases the efficiency of coughing.


Patients with high blood pressure, diabetes and some types of heart, prostate, eye and thyroid problems should exercise care when using dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin products.

Patients older than 60 years are more likely to experience adverse reactions to dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin products.

Respiratory Depression

Like all opioids, dihydrocodeine may cause respiratory depression, a dangerous and sometimes fatal breathing condition. Opioids depress the brain’s urge to breathe, preventing the lungs from adequately exchanging spent carbon dioxide for fresh oxygen. This causes oxygen starvation and toxic carbon levels. Symptoms of respiratory depression include slow, shallow and uneven breathing and a bluish tint around the victim’s eyes, mouth and fingertips.

Respiratory depression occurs more frequently in elderly or debilitated consumers, especially at high initial doses in opioid-naïve patients, or when used along with other medications that depress breathing.

Patients with the breathing problem COPD or the heart problem known as cor pulmonale should exercise caution when using dihydrocodeine, as should patients with diminished lung capacity, high carbon dioxide levels, low oxygen levels or pre-existing respiratory depression.

Hypotensive Effect

The vasodilation associated with dihydrocodeine can cause low blood pressure, or hypotension. This hypotensive effect can adversely affect patients who already have trouble maintaining an adequate blood pressure, either because they have lost a lot of blood or because they have used a drug that lowers blood pressure.

Dihydrocodeine may cause orthostatic hypotension, or blood pressure that crashes when the individual rises quickly.

Healthcare providers should use caution when administering dihydrocodeine to patients in circulatory shock, as dihydrocodeine can widen blood vessels in a way that further lowers blood pressure and the amount of blood available for the heart to pump.


Regular use of dihydrocodeine for more than a few weeks may cause the consumer to become physically dependent on opioids. An opioid-dependent person experiences withdrawal symptoms when he stops taking dihydrocodeine abruptly. Physicians should use appropriate care when prescribing dihydrocodeine, especially to patients with a history of substance abuse or drug dependence.


Dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin products may make the consumer feel dizzy or drowsy, or impair her mental and physical performance. Alcohol and other drugs may enhance these effects. A consumer should not drive a car or operate heavy machinery until she knows how this combination drug will affect her.

Elderly or debilitated patients should use dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin with caution. Individuals with some medical conditions should exercise care when using this combination product, especially those with Addison’s disease, asthma, COPD, diabetes, head injury, high or low blood pressure and some types of thyroid, prostate or urinary problems. Patients struggling with alcoholism or delirium tremens, sometimes called “DTs,” should use this product with care, as should those with decreased respiratory function due to emphysema, severe obesity, cor pulmonale or severe curvature of the spine. Healthcare providers should exercise caution when administering this medication to patients in a coma, with pre-existing CNS depression or intracranial fluid pressure inside the skull, or to those with the severe mental condition, toxic psychosis. This medication may cause or worsen seizures in some circumstances.


People who are hypersensitive to dihydrocodeine, codeine, phenylephrine or guaifenesin should not take products containing these substances.

Healthcare providers should not administer dihydrocodeine in any circumstance where opioids are not appropriate, especially to patients suffering respiratory depression in unmonitored settings or in locations without resuscitation equipment. Other instances where opioids like dihydrocodeine are not appropriate include in asthma patients, those suffering high carbon dioxide levels or in patients with the serious type of bowel obstruction known as paralytic ileus.

Phenylephrine is not appropriate for patients with high blood pressure, asthma, peptic ulcer and some types of severe heart disease and eye problems.

Children younger than two years old are more susceptible to respiratory depression, coma and death. Very young children are more sensitive to the effects of this preparation, especially the way phenylephrine can raise blood pressure. This medication is not appropriate for children younger than six years old, as

Pregnancy, Labor and Delivery, Breastfeeding

The FDA classifies dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin combinations as Pregnancy Category C drugs, meaning there are not adequate studies to determine the risks this drug may pose to a pregnant woman or fetus, or to the reproductive capabilities of males and females. A pregnant woman should only take dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin products of the benefits clearly outweigh the possible risks, especially during the first three months of pregnancy.

Babies born to women who regularly take dihydrocodeine will be born opioid-dependent and suffer withdrawal symptoms in the first days or weeks of life. A baby suffering neonatal withdrawal is irritable and cries excessively, has rapid breathing and increased stools, hyperactive reflexes, sneezing, yawning and vomiting. Medical specialists are still working to come to a consensus on the best way to treat withdrawal symptoms in infants.

Using dihydrocodeine during labor and delivery may cause the newborn to suffer respiratory depression.

Dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin may pass into human milk and onto a nursing baby. Mothers should not breastfeed while taking this preparation.

Special Risk Consumers

Elderly patients should use dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin with care.

Patients with liver problems should exercise caution when using opioids. The liver metabolizes dihydrocodeine into smaller metabolites that the body eliminates through urine. Physicians should monitor the effects dihydrocodeine has on consumers with liver dysfunction.

Physicians should prescribe lower dosages of dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin combination products to patients whose kidneys do not work well.

Dihydrocodeine works on smooth muscles, like the biliary valve that controls the flow of bile and pancreatic juices into the small intestine. Patients with biliary tract disease, including pancreatitis, should use preparations containing dihydrocodeine with caution.

Drug Interactions

Products containing dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin can interact with other medications in undesirable or dangerous ways.

Other drugs that depress the nervous system, including other opioids, alcohol, sedatives and tranquilizers, muscle relaxants, anti-psychotic drugs and some medications that soothe nausea and vomiting, can enhance the CNS depressive effects of dihydrocodeine. When a patient needs both dihydrocodeine and the other CNS depressant, physicians should consider reducing the dose of one or both medications.

Phenylephrine can interfere with some blood pressure lowering drugs, including methyldopa, mecamylamine, reserpine and veratrum alkaloids.

Many people take monoamine oxidase inhibitors, or MAOIs, to treat high blood pressure or depression. Dihydrocodeine can interact with MAOIs to excite the central nervous system and increase high blood pressure, worsening hypertension.

Phenylephrine can interact with MAOIs and another anti-hypertension medication, beta-adrenergic blockers, to increase the effects of phenylephrine.

Side effects

Like all medications, dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin can cause side effects for some consumers.

Dihydrocodeine consumers report feeling lightheaded, sedated, dizzy or drowsy, and commonly experience fatigue, sweating, nausea and vomiting, constipation, itching and skin reactions. Except for constipation, most consumers develop tolerance to most of these side effects.

Dihydrocodeine may cause other adverse reactions, including respiratory depression, orthostatic hypotension, suppression of a necessary cough, confusion, diarrhea, pinpoint pupils, stomachache or stomach upset, dry mouth, loss of appetite, spasm of the biliary tract or urinary trouble.

Dihydrocodeine may cause opioid-dependence and withdrawal symptoms upon sudden cessation.

Rarely, someone can suffer a hypersensitivity reaction or a dangerous form of an allergic reaction known as anaphylaxis after taking dihydrocodeine, or experience hallucinations, vivid dreams or serious kidney problems.

Phenylephrine and guaifenesin may cause extreme fatigue, giddiness, nausea, dry mouth, irregular heartbeat, increased irritability or flushing, which is an uncomfortable warmth and redness that spreads over the face and neck. These ingredients may cause excitability, especially in children.


Dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin overdose is a serious medical emergency that could result in death. Nearly 15,000 Americans die from overdose of prescription painkillers, including dihydrocodeine, every year.

Overdose patients will exhibit symptoms such as pinpoint pupils, respiratory depression, extreme sleepiness that worsens to coma, limp muscles and cold, clammy skin. The patient may experience seizures or collapse of the circulatory system; death may occur.

Overdose of dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin requires immediate care. Emergency department workers will establish an airway to help the patient breathe. Nurses will give the patient ipecac to induce vomiting then introduce activate charcoal into the stomach to absorb excess medication. The patient will receive medicine to encourage a bowel movement.

Nurses will start intravenous fluids to stabilize blood pressure. Physicians may administer intravenous or oral naloxone or other drugs to counteract respiratory depression. These drugs interfere with dihydrocodeine, causing withdrawal symptoms in opioid-dependent patients and complicating treatment for overdose.


Recreational drug abusers target dihydrocodeine because of the way the drug gets the abuser high. The DEA classifies dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin preparations as class III drugs, meaning the pose about the same threat for abuse as anabolic steroids or Tylenol with codeine.

Recreational drug abuse increases the risk for adverse reactions, overdose, addiction and opioid-dependence. To reduce the risk for abuse, dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin combination drugs are available only with a prescription.


An opioid-dependent person will begin to feel withdrawal symptoms a few hours after the last dose of dihydrocodeine and continue to feel uncomfortable for five or more days.

Someone going through dihydrocodeine withdrawal will feel irritable, restless and anxious and suffer symptoms like insomnia, excessive sweating and irregular heartbeat.

To avoid withdrawal symptoms, physicians recommend tapering dihydrocodeine use by taking smaller doses each day. This tapering method is usually successful but overpowering and persistent withdrawal symptoms prevent some people from discontinuing this drug when they no longer need it to treat symptoms.


Many local healthcare institutions now offer detoxification services to help people overcome stubborn or severe withdrawal symptoms. During detoxification, patients receive drugs to lower opioid levels along with medications to ease withdrawal symptoms.

Many informed consumers choose rapid detox, a more humane and efficient approach to detoxification. During rapid detox, anesthesiologists sedate and anesthetize the patient before administering the standard detoxification and anti-withdrawal drugs. Rapid detox allows the patient to doze in a comfortable “twilight sleep,” unaware of the difficult detoxification process.


Caregivers should store dihydrocodeine bitartrate, phenylephrine hydrochloride and guaifenesin products at temperatures ranging between 59 and 86 degrees Fahrenheit. Consumers should keep this medication in a light-resistant container, out of the reach of children.