Hydrochlorothiazide (HCTZ or HCT) is a generic prescription medication, found most often under the brand name Microzide, that treats swelling from edema or water retention, often associated with high blood pressure, congestive heart failure, cirrhosis of the liver, kidney failure, nephrotic syndrome, and corticosteroid prescriptions. To treat heart conditions, this prescription is usually used in combination with other drugs that manage blood pressure, cholesterol, arrhythmias, and more.
Hydrochlorothiazide is the second most commonly prescribed anti-hypertensive medication in the United States, and it has been around for decades. This prescription was approved by the Food and Drug Administration (FDA) in 1959.
Although abuse of diuretics like hydrochlorothiazide is unusual, these drugs are sometimes abused alongside performance-enhancing substances to avoid detection in drug tests. This can be dangerous, because the side effects associated with a large hydrochlorothiazide dosage can be harmful and performance-enhancing drugs are typically very dangerous, too.
Hydrochlorothiazide Side Effects
Typically, uncomfortable side effects associated with hydrochlorothiazide use can be managed with a physician’s help by adjusting the dose. Common side effects include:
- Muscle weakness
- Blurry vision
There are some serious HCTZ side effects, including allergic reactions, that may require emergency medical treatment.
Very serious side effects include:
- Severe stomach pain
- Sustained loss of appetite
- Dark urine or clay-colored stool
- Bleeding or bruising that is unusual
- Skin rash leading to peeling skin
- Fast or uneven heartbeat
- Tingling or numbness
- Yellowing of the eyes or skin (jaundice)
Diuretic drugs like hydrochlorothiazide specifically increase how much urine the body produces to reduce edema or swelling. While this is not an effect that many people seek out as a high, there are some reports of substance abuse of this drug.
Of 92,557 people who reported adverse side effects related to hydrochlorothiazide, 112 people reported that abuse or addiction to the substance was one of those effects. This was most often among people who had taken the drug for more than a decade, and could indicate either relapse behaviors from previous addictions or drug abuse alongside taking hydrochlorothiazide as prescribed.
Unlike many prescription drugs, more women than men abused the substance, but this may be due to women’s physiology involving higher risk of water retention than men. Reportedly, 57.8% of the people who abused the drug were women, and 42.2% were men. About 29% were at least 60 years old, and about 28% were 40–49 years old.
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Doping with Diuretics
Athletes may abuse diuretics to rapidly lose weight through dehydration so they can compete in a lower weight class or meet specific weight requirements. In addition, diuretics can flush out traces of performance-enhancing drugs like stimulants or steroids in urine tests. Many diuretics are listed as illegal for competition by the World Anti-Doping Agency (WADA).
In 2008, WADA laboratories reported that 7.9% of banned substances found on tests were diuretics, including hydrochlorothiazide, which was the most commonly detected medication, found in 137 cases (31.4% of positive cases). That year, hydrochlorothiazide overtook furosemide as the most abused diuretic drug.
Although WADA routinely tests athletes both during and between competitions, hydrochlorothiazide has a very short half-life, and is typically eliminated from the body within 24–48 hours after it is consumed. This half-life can be shortened sometimes with sustained exercise for an hour or longer. Consistent drug testing is important to find instances of abuse.
Long-Term Abuse Dangers
Any side effects can be managed with the help of a physician, but if the drug is consistently abused, long-term harm can include kidney damage, stomach damage, and cardiovascular damage from low blood pressure and not enough electrolytes, which are excreted through urine.
Hydrochlorothiazide does not cause specific withdrawal symptoms, but quitting this medication suddenly can lead to higher blood pressure, heart problems, and an increase in water retention from the underlying medical conditions that the prescription drug treats. Simply stopping this medication without help from the prescribing physician can lead to a rebound of symptoms that hydrochlorothiazide treats, which can be life-threatening.
Although overdose on hydrochlorothiazide is rare, it can happen. Poisoning occurs when a person takes too much of this medication, either accidentally, purposefully, or by combining it with another medication that enhances the drug’s effects.
- Muscle weakness
- Extreme dry mouth and thirst
- Physical weakness
Drug Interactions with Hydrochlorothiazide
Because hydrochlorothiazide interacts with blood pressure and swelling related to chronic health problems, this medication can interact with several other prescriptions, and illicit drugs can cause serious harm or make this medication fail to work appropriately. Stimulant drugs like Adderall, Ritalin, cocaine, meth, MDMA, or bath salts can change heart rate, blood pressure, and breathing rate by raising them to dangerous levels. They can also raise body temperature, leading to kidney damage. Heart and kidney damage can be exacerbated by hydrochlorothiazide, so any current or past abuse of these stimulant medications must be reported to a physician if they prescribe this drug.
Other drugs that interact with hydrochlorothiazide include:
- Digoxin, which treats heart damage and failure
- Cholestyramine, which lowers cholesterol levels
- Barbiturates like phenobarbital and secobarbital
- Cholestyramine, which treats high cholesterol
- Colestipol, which also treats cholesterol
- Other sedatives and muscle relaxers
- Medication for seizures
- Depression and anxiety prescriptions
One of the most serious drugs that impacts hydrochlorothiazide is alcohol. While alcohol is a legal intoxicant, it is a sedative that interacts poorly with many prescription medications. Alcohol combined with hydrochlorothiazide can rapidly drop blood pressure, leading to fainting or extreme dizziness. It can also make other side effects, like cognitive or vision changes, worse.
Treatment for Prescription Drug Abuse and Doping Among Athletes
Anyone who struggles with addiction to prescription drugs, or who has a loved one who may have problems with substance abuse, can locate nearby evidence-based treatment through the Substance Abuse and Mental Health Services Administration’s (SAMHSA) online treatment finder. For athletes or exercise enthusiasts who have abused diuretics to enhance performance, there is help in the form of Anti-Doping Advocacy Organizations and education programs about the dangers of performance-enhancing drugs.